Jonny Hisdal

• Niemi, Essi Maria; Nyman, Tuula Anneli; Attramadal, Håvard; Hoel, Henrik; Rosales, Antonio & Hisdal, Jonny [Show all 7 contributors for this article] (2026). Proteomic evaluation and comparison of native and decellularized human saphenous vein extracellular matrices. Frontiers in Bioengineering and Biotechnology. 14. doi: 10.3389/fbioe.2026.1773372. Full text in Research Archive
• Bonnevie-Svendsen, Martin; Edvardsson, Erle Viktoria; Oppen, Kjersti; Melau, Jørgen; Nyborg, Christoffer & Sæter, Frode Wirum [Show all 9 contributors for this article] (2026). Cardiac troponin patterns in athletes completing Norseman Xtreme Triathlon. BMJ Open sport & exercise medicine. 12(2). doi: 10.1136/bmjsem-2025-002810. Full text in Research Archive
• Koistinaho, Aura; Lie, Sole Lindvåg; Landsverk, Svein Aslak; Lenz, Harald; Rehn, Marius & Hisdal, Jonny [Show all 7 contributors for this article] (2026). Peripheral intravenous waveform analysis for evaluating volume status in healthy volunteers and mechanically ventilated patients. Journal of clinical monitoring and computing. ISSN 1387-1307. doi: 10.1007/s10877-025-01408-6. Full text in Research Archive
• Grannes, Johan; Callender, Nigel Allan; Gonzalez, Adam M.; Hisdal, Jonny; Vårvik, Fredrik Tonstad & Bjørnsen, Thomas (2026). Acute effect of citrulline malate on flow-mediated dilation and serum pharmacodynamics in healthy young males. Frontiers in Physiology. 17. doi: 10.3389/fphys.2026.1773582. Full text in Research Archive Show summary

  Introduction: The use of ergogenic compounds has gained increasing popularity among individuals who wish to improve performance and recover faster from their workouts. Among these products is citrulline malate (CitMal), a popular dietary supplement that is suggested to enhance nitric oxide (NO)-mediated vasodilation and muscle blood flow.Methods: To evaluate effects on arterial function, flow-mediated dilation (FMD) of the brachial artery during active hyperemia was measured in 12 healthy, recreationally active males (23 ± 3 years) before and after (60- and 120-min post) consuming either 6 g CitMal, 12 g CitMal, or a taste-matched placebo. The study used a randomized, double-blind, placebo-controlled, within-subject counterbalanced crossover design with ≥7-day washouts.Results: Repeated measures ANOVA revealed no significant interaction (p = 0.315) or time effect (p = 0.649) in corrected FMD% at 60- and 120-min after intake of placebo, 6 g CitMal, and 12 g CitMal. There were also no significant differences (p = 0.301) between doses at any timepoint. A subgroup of six participants completed two additional visits to assess the effect of CitMal ingestion on serum markers involved in NO production. Over 120-min post-consumption, both doses significantly increased peak serum concentrations of citrulline (6 g: 504.7 ± 139.7; 12 g: 881.9 ± 216.7 μM), arginine (6 g: 70.2 ± 20.4; 12 g: 101.8 ± 36.2 μM), and ornithine (6 g: 27.9 ± 14.2; 12 g: 56.5 ± 30.0 μM) from baseline (all p < 0.001), with greater increases following 12 g (all p < 0.05). Likewise, arginine-to-dimethylarginine ratios (SDMA and ADMA) increased from baseline (SDMA, 6 g: 114.1 ± 24.2; 12 g: 166.2 ± 43.7; ADMA, 6 g: 119.2 ± 31.8; 12 g: 169.1 ± 29.1; all p < 0.001), with greater increases following 12 g (p < 0.05).Discussion: Collectively, these findings suggest that neither 6 g nor 12 g of CitMal significantly enhance FMD within 120 min, despite marked increases in biochemical markers favorable to NO production. To our knowledge, this is the first study to compare acute doses of CitMal up to 12 g in relation to brachial artery FMD. These results indicate that acute vascular responses to CitMal may be limited by physiological ceiling effects and that potential vascular benefits may depend on longer-term supplementation, the presence of an exercise stimulus, or populations with impaired endothelial function.

• Kalvøy, Håvard; Hisdal, Jonny & Tronstad, Christian (2025). Toe digit pulsation measurement by impedance plethysmography in miniaturized devices: An early feasibility test. Journal of Electrical Bioimpedance. 16(1), p. 150–152. doi: 10.2478/joeb-2025-0020. Full text in Research Archive Show summary

  This early feasibility test explores impedance plethysmography (IPG) for detecting toe pulse waves using a setup suited for miniaturized devices. Conventional tests often miss micro-circulatory impairment, which is critical for wound healing and limb survival. We designed a flexible 3D-printed clamp with Ag/AgCl electrodes positioned on the inner big toe to target the lateral plantar digital artery. 50 kHz impedance measurements were performed on a healthy volunteer using 3D-printed electrode clamp for a tetrapolar configuration. Custom designed flexible electrodes were tested with and without contact gel. Preliminary results suggest that IPG can capture distal pulsatile signals, motivating further exploration of the potential for early detection of peripheral vascular dysfunction.

• Tungesvik, Helene Melsom; Padrela, Beatriz; Groote, Inge Rasmus; Bjørnerud, Atle; Geier, Oliver Marcel & Hisdal, Jonny [Show all 8 contributors for this article] (2025). Imaging cerebral circulation in long-term anabolic-androgenic steroid users and non-using weightlifters. Drug and Alcohol Dependence. ISSN 0376-8716. 275, p. 112829–112829. doi: 10.1016/j.drugalcdep.2025.112829. Full text in Research Archive Show summary

  Background: Anabolic-androgenic steroids (AAS) are commonly used by recreational weightlifters for performance enhancement, despite associated health risks, including cardiovascular and brain effects. This study investigates the cerebrovascular effects of prolonged AAS use in male weightlifters, focusing on cerebral blood flow (CBF) and other indicators of cerebrovascular health. Methods: Eighty-six males were included, with 41 current consumers of AAS and 45 non-using weightlifting controls. Cerebrovascular health was evaluated using magnetic resonance imaging (MRI) pseudo-continuous arterial spin labeling (PCASL) derivatives to measure CBF and spatial coefficient of variation (sCoV) of CBF in gray matter. Additionally, MRI T2-weighted fluid-attenuated inversion recovery (FLAIR) sequences were used to analyze white matter hyperintensities as a marker of small-vessel disease. Results: AAS consumers had significantly higher sCoV than weightlifting controls (p = 0.001). Further, sCoV in total gray matter correlated with testosterone/epitestosterone ratio and total years of AAS use. No significant differences were found in CBF or white matter hyperintensity volume. Conclusion: These findings indicate that long-term AAS use may impact cerebrovascular health, evidenced by increased sCoV. Although cerebral perfusion was unaffected, elevated sCoV suggest that AAS use may pose a risk for cerebrovascular pathology later in life. Keywords: Anabolic androgenic steroids; Arterial spin labeling (ASL) perfusion MRI; Cerebral blood flow; Spatial coefficient of variation; Substance misuse.

• Kyte, Ferdinand Grov; Kyte, Karoline Holsen; Skinstad, Linn; Hisdal, Jonny & Stensrud, Trine (2025). Breathing Reserve and Lung Function in Female Elite Runners. Sports. 13(7). doi: 10.3390/sports13070231. Full text in Research Archive Show summary

  Breathing reserve (BR) is the remaining proportion of achievable minute ventilation that remains unutilized at total exhaustion during exercise. Previous studies have found a smaller BR in endurance-trained athletes compared to untrained controls. However, most of these studies have examined men. Given that women have a greater ventilatory limitation than stature-matched men, the present cross-sectional study aimed to investigate how this sex difference influences BR and lung function tests in endurance-trained females compared to matched, untrained females. To obtain further insight, we also aimed to investigate whether VO2max serves as a predictor of BR. We examined 15 female elite runners and 15 healthy, matched female controls aged 24–33 years with regard to pulmonary function, MVV, VEmax, BR, and VO2max. The elite runner group had a median BR of 5%, while that of the controls was 21%, representing a significant difference. Lung function tests showed no differences between the two groups. A moderate association was found between VO2max and BR. The female elite runners demonstrated a lower BR than the group of matched, untrained controls, which was lower than that found for male elite athletes in previous studies. This may indicate a greater ventilatory demand in female relative to male endurance athletes.

• Edwin, Gorm von Gohren; Skraastad, Berit Kristine Bendixen; Hisdal, Jonny; Wisløff, Torbjørn; Sundhagen, Jon Otto & Kazmi, Syed Sajid Hussain (2025). Assessment of Transserosal Microcirculation with Visible Light Spectroscopy and Laser Doppler Flowmetry in Patients with Median Arcuate Ligament Syndrome and Chronic Mesenteric Ischemia. Vascular Health and Risk Management. ISSN 1176-6344. 21, p. 61–69. doi: 10.2147/VHRM.S484787. Full text in Research Archive Show summary

  Introduction: Previous studies with visible light spectroscopy (VLS) and laser Doppler flowmetry (LDF) have shown reduced mucosal circulation of the stomach and duodenal wall in patients with median arcuate ligament syndrome (MALS) and chronic mesenteric ischemia (CMI). However, transserosal microcirculatory assessment during the operative treatment of patients with these conditions has not yet been performed. We aimed to investigate if laparoscopic decompression for MALS and aortomesenteric bypass in CMI can result in immediate measurable increase in the microcirculation in stomach and duodenum. Patients and Methods: In a single center, prospective comparative cohort study, twenty-eight patients suspected of MALS, and eleven with CMI underwent assessment of transserosal microcirculation of stomach and duodenum with Visible Light Spectroscopy (VLS) and Laser Doppler flowmetry (LDF), during surgery. Patients with computed tomography angiography (CTA) verified stenosis grade ≥ 50% in MALS and ≥ 70% in CMI were included in the study. Duplex ultrasound (DUS) was performed before and after the surgical treatment. The changes in the pre- and postoperative microcirculation were calculated with paired sample t-test. Results: VLS showed significant increase in the transserosal relative hemoglobin concentration (rHb) after laparoscopic decompression in patients with MALS (Stomach, before: 58AU± 13, after: 62AU± 14, p = 0.017) and (Duodenum, before: 62AU± 15, after:70AU± 15, p = 0.004). Furthermore, a significantly increased blood flow was found in duodenum (Before: 276AU± 89, After: 315AU± 93, p = 0.015). However, the SaO2 was decreased significantly in the stomach (Before: 86AU± 10, After: 82AU± 14, p = 0.015), but remained unchanged in the duodenal serosa.The study did not find any increase in the microcirculation of the CMI patients after revascularization. The baseline transserosal microcirculation was indifferent between the groups. Conclusion: Laparoscopic decompression leads to enhanced transserosal microcirculation in stomach and duodenum in the patients with MALS. The baseline transserosal microcirculation in stomach and duodenum is indifferent in the MALS and CMI.

• Callender, Nigel Allan; Høiseth, Lars Øivind; Mathiesen, Iacob & Hisdal, Jonny (2025). Intermittent negative pressure influences popliteal artery shear rate during supine and sitting postures. VASA. ISSN 0301-1526. 54(2), p. 113–123. doi: 10.1024/0301-1526/a001172. Full text in Research Archive Show summary

  Background: Intermittent negative pressure is an emerging treatment for lower limb vascular disease but the specific physiological effects, particularly upon large artery haemodynamics are unclear. This study examined the influence of intermittent negative pressure upon popliteal artery shear rate during both supine and sitting postures. Participants and methods: Eleven healthy participants (5 female; age: 28.3 ± 5.8 y; weight: 69.6 ± 9.8 kg, height: 1.75 ± 0.07 m) received intermittent negative pressure (–37 mmHg; 9.5-sec on, 7.5-sec off), upon the lower leg during both supine and sitting postures. Popliteal artery blood flow and shear rate were recorded (duplex ultrasound), accompanied by heart rate (3-lead ECG) and blood pressure (volume clamp method). Results: Compared to sitting, a supine posture led to greater mean shear rate during baseline (supine: 21[9]; sitting: 17[13] sec−1; all median [IQR]) and negative pressure phases (supine: 24[15]; sitting: 17[14] sec−1; both p<0.05). While supine, negative pressure raised mean shear rate above baseline levels (p<0.05) and reduced it upon return to atmospheric pressure (p < 0.05). In sitting, mean shear rate only differed from baseline at the points of peak and minimum shear (peak:18[17]; minimum: 10[9] sec−1; both p<0.05). Shear pattern (oscillatory shear index) showed changes from baseline during both postures (p<0.05), but was not different between postures. Conclusions: Intermittent negative pressure influenced lower limb popliteal artery shear rate during both the supine and sitting postures, the effect was greater while supine. Fluctuation in shear pattern seen during both positions may account for positive clinical effects observed following intermittent negative pressure treatment. These findings are framed against previous work investigating clinical populations. Future work should investigate any differences in lower limb haemodynamics and markers of endothelial function among patients with vascular disease.

• Morton, William James; Melau, Jørgen; Olsen, Roar A.; Løvvik, Ole Martin; Hisdal, Jonny & Søvik, Signe (2025). Thermal physiology of open water wetsuited swimming: A cohort study. Temperature. ISSN 2332-8940. 12(3), p. 245–263. doi: 10.1080/23328940.2025.2479893. Full text in Research Archive Show summary

  Swimming in cold water is intrinsically unsafe. One of the threats is a fall in deep-body temperature, which adversely affects all body systems and increases the risk of death. Wetsuits mitigate, but do not negate this threat. Environmental conditions may confound findings from laboratory studies or mathematical models. The study aimed to elucidate associations and patterns of deep-body temperature change in open water wetsuited swimmers, thus facilitating risk assessment and improving swimmer safety. In this exploratory cohort study, following collection of anthropomorphic data including a Dual-energy X-ray Absorptiometry scan, deep-body temperature was continuously measured in 76 open water swims by 31 wetsuited swimmers in water temperatures ranging from 8.4°C to 24.5°C. The temperature trajectories were analyzed by piece-wise and linear mixed model regression. Registered with clinicaltrials.gov NCT06685627. Following immersion, there was a tri-phasic deep-body temperature trajectory, although not all phases were present in all swims: an initial rise, then a plateau phase and then thermal decompensation. Water temperature was correlated with the duration of these phases, as was body habitus for the initial rise. Minimum deep-body temperature was correlated with pre-swim temperature. Despite environmental and individual variations, this paper identified a tri-phasic deep-body temperature trajectory for wetsuited swimmers and proposed physiological mechanisms that may account for them. The tri-phasic pattern of an initial rise, a plateau phase and then thermal decompensation, may be useful in assessing the risks of open water swimming and may facilitate development and validation of deep-body temperature models for wetsuited swimmers.

• Morton, William James; Melau, Jørgen; Olsen, Roar A.; Løvvik, Ole Martin; Hisdal, Jonny & Søvik, Signe (2024). Manual Dexterity in Open-Water Wetsuited Swimmers: A Cohort Crossover Study. International Journal of Sports Physiology and Performance (IJSPP). ISSN 1555-0265. 20(2), p. 213–223. doi: 10.1123/ijspp.2024-0100. Full text in Research Archive Show summary

  Purpose: Laboratory studies have demonstrated that manual dexterity decreases with increasing cold, which may adverselyaffect performance. Dexterity may be impaired by cooling of the hand, cooling of the lower motor neurons, and cognitiveimpairment. Wetsuits are commonly used in open-water swimming and are mandated in some situations. This study investigatesthe effects of cold-water wetsuited swimming on dexterity. Methods: Five male and 4 female trained swimmers were recruited forthis cohort crossover study. Following dual-energy X-ray absorptiometry scans to determine body composition, they swam in afreshwater lake on 7 occasions with water temperatures between 24.5 °C and 8.4 °C. Dexterity was measured preswim andpostswim with a “nut–washer–bolt assembly time test” and cognition with a Stroop test. Core and peripheral body temperatureswere continuously monitored. Effects were analyzed by linear mixed-model regression. Results: Pre–post swim difference intime to complete the nut–bolt assembly increased as water temperatures decreased (1.0 s, 95% CI, 0.5–1.5 per 1 °C, P < .0001;R2 = .456), to a maximum of 14.7 seconds (95% CI, 3.3–26.0). This represented a 47.5% increase in assembly time from 24.5 °Cto 8.4 °C, which we consider to be of practical significance. Decreased dexterity was associated with decreased forearm andscapular temperature and decreased cognitive function. Body composition did not affect dexterity, cognitive function, or bodytemperature during swims. Water temperature did not affect swim speed. Conclusions: Despite the use of wetsuits, manualdexterity decreased with cold-water swimming. Swimmers, triathletes, and event organizers should consider the implications forsafety, performance, and equipment utilization.

• Bonnevie-Svendsen, Martin; Nyborg, Christoffer; Bratset, Vibeke; Melau, Jørgen & Hisdal, Jonny (2024). Transient changes in L-arginine, asymmetric and symmetric dimethyl arginine in triathletes following Norseman Xtreme Triathlon. Frontiers in Physiology. 15, p. 1–7. doi: 10.3389/fphys.2024.1451038. Full text in Research Archive Show summary

  Arterial vasodilation is dependent on nitric oxide synthesized from L-arginine by endothelial nitric oxide synthase. Triathletes are reported to display altered serum concentrations of nitric oxide metabolites such as L-arginine, asymmetric dimethyl arginine (ADMA) and symmetric dimethyl arginine (SDMA) shortly after completing long-distance triathlon races. In other populations, similar changes to nitric oxide metabolites are established risk markers of cardiovascular disease. The objective of this study was to assess serum concentrations of metabolites for endothelial nitric oxide synthesis in triathletes one week following a long-distance triathlon race. In this prospective observational study, we used high-performance liquid chromatography to measure circulating concentrations of L-arginine, ADMA, and SDMA in triathletes. Venous blood samples were collected before, immediately after, day one, and one week following the triathlon race. Serum concentrations and L-arginine/ADMA ratio were determined for each time-point and compared to baseline. L-arginine/ADMA ratio was reduced on day one (147 ± 32 vs 163 ± 40, p < 0.02). ADMA was reduced immediately after and increased at day one and remained elevated at one week (0.29 ± 0.05 μM, p < 0.001, 0.44 ± 0.08 μM, p < 0.001 and 0.42 ± 0.07 μM, p = 0.04, respectively vs 0.40 ± 0.05 μM). SDMA was increased at all time-points when compared to baseline (0.48 ± 0.10 μM, p < 0.001, 0.53 ± 0.11 μM, p < 0.001 and 0.42 ± 0.08 μM, p = 0.048 vs 0.38 ± 0.05 μM). L-arginine was only decreased immediately after (46.0 ± 9.3 μM vs. 64.6 ± 16.1 μM, p < 0.001). Long-distance triathlon racing induces altered levels of metabolites for endothelial nitric oxide production that mostly normalizes within one week following racing. The clinical relevance of these transient changes has yet to be elucidated in the athletic population.

• Callender, Nigel Allan; Høiseth, Lars Øivind & Hisdal, Jonny (2024). External negative pressure transiently reduces intravenous pressure and augments the arteriovenous pressure gradient in the affected limb segment. PLOS ONE. 19(12). doi: 10.1371/journal.pone.0315231. Full text in Research Archive Show summary

  Recently intermittent negative pressure has emerged as a potential treatment in vascular disease and has similarities with established experimental interventions such as lower body negative pressure. The direct, local influences of either method upon intravascular pressure still require some clarification however, particularly in the immediate moments following onset. We investigated the acute intravascular pressure responses to intermittent cycles of negative pressure in the supine and sitting postures. Fifteen participants (6 female) received intermittent negative pressure cycles (-37 mmHg; 9.5-sec on, 7.5-sec off) upon the lower leg in both postures. Saphenous venous (n = 15), and dorsalis pedis artery pressure (n = 3) were recorded via pressure catheter, alongside beat-by-beat systemic cardiovascular parameters (heart rate and blood pressure; n = 15), from which the arteriovenous pressure gradient was ultimately derived. Negative pressure induced a transient reduction in local intravenous pressure (Supine: 14±3 mmHg to -18±6 mmHg, p<0.001; Sitting: 58±10 mmHg to 41±10 mmHg, p<0.001). Rate of venous pressure recovery during the negative pressure plateau phase was faster during sitting, than supine (1.94±0.72 vs. 1.06±0.69 mmHg·sec-1; p = 0.002). Local intraarterial pressure did not change. External negative pressure readily transmits to the superficial intravenous environment of the leg and transiently augments the arteriovenous pressure gradient. The greatest and most sustained effect was during the supine position. The augmented arteriovenous gradient might briefly produce Poiseuille-dependent haemodynamics before local autoregulatory mechanisms engage. These findings benefit understanding of the immediate in-vivo effects of negative pressure upon the local vasculature, and may partly account for the positive clinical effects of intermittent negative pressure treatments in vascular disease.

• Mansoor, Saira Mauland; Jørgensen, Jørgen Joakim; Hisdal, Jonny & Rabben, Toril (2024). Thirty-Nine Percent of Patients with a Ruptured Abdominal Aortic Aneurysm (AAA) Have an Incidentally Detected AAA Prior to Rupture. Annals of Vascular Surgery. ISSN 0890-5096. 108, p. 148–156. doi: 10.1016/j.avsg.2024.04.017. Full text in Research Archive Show summary

  Background Abdominal aortic aneurysm (AAA) screening has been offered to 65-year-old men living in Oslo, Norway, since May 2011. A significant number of AAA-related deaths occurred in individuals who are not eligible for screening. The primary aim of this study was to describe the group of patients admitted to Oslo University Hospital with a ruptured AAA after the implementation of the local AAA screening project. The following parameters were investigated: AAA detection before rupture, surveillance status, eligibility for screening, and comorbidities. We also sought to compare outcomes (repair rates and 30-day mortality) between patients with and without an incidentally detected AAA prior to rupture. Methods This cohort study included patients admitted acutely to Oslo University Hospital due to a symptomatic or ruptured AAA in the period January 2011 to December 2022. Data on demographics, prior AAA detection, surveillance status, treatment, and mortality were collected retrospectively through electronic medical records. Results We identified 200 patients with a symptomatic or ruptured AAA, among which 79 (40%) had an AAA detected before rupture—one (1%) through screening and 78 (39%) incidentally. Up to 30% of the incidentally detected AAAs were not under any surveillance. Six patients were found eligible for screening: one had attended, three were non-attenders, and two had not been invited. Patients with an incidentally detected AAA before rupture had a more advanced age and a significantly higher degree of comorbidities than patients without a previously detected AAA, and the repair rates in these groups were 56% and 84%, respectively (P < 0.001). Adjusted for comorbidities and risk factors, the odds ratio for repair among patients with incidentally detected AAA was 0.56 (P = 0.292). The 30-day mortality was not significantly different between the two groups (P = 0.097). Conclusions Most patients with a ruptured AAA were not eligible for screening, but 39% of the patients had an incidentally detected AAA prior to rupture. Standardized reporting and follow-up of incidentally detected AAAs is thus identified as an additional measure to organized screening in the effort to reduce AAA-related mortality.

• Havnes, Ingrid Amalia; Henriksen, Hans Christian Bordado; Johansen, Per Wiik; Bjørnebekk, Astrid Kristine; Neupane, Sudan Prasad & Hisdal, Jonny [Show all 11 contributors for this article] (2024). Off-label use of clomiphene citrate to treat anabolic androgenic steroid induced hypogonadism upon cessation among men (CloTASH) – A pilot study protocol. MethodsX. 13. doi: 10.1016/j.mex.2024.102810. Full text in Research Archive Show summary

  Background Non-prescribed anabolic androgenic steroid (AAS) use is associated with AAS-induced hypogonadism (ASIH), and metabolic, cardiovascular, and mental health risks. Symptoms of ASIH (fatigue, depression, anxiety, sexual dysfunction) are hard to endure following cessation, but there is no consensus on whether endocrine treatment should be used to treat ASIH. This proof-of-concept study aims to explore safety of off-label clomiphene citrate therapy, whether the treatment will reduce the symptoms of androgen deficiency, and to study changes in health risks after cessation. Methods In this open-labeled non-randomized off-label hormone intervention pilot study, we shall include males with AAS dependence intending to cease use. The 16-week intervention included clomiphene citrate, transdermal testosterone gel for the first four weeks and optional human chorionic gonadotropin (hCG) from week 4 if low treatment response. Measures of physical and mental health will be examined from ongoing AAS use, during the intervention, and at 6- and 12 months post cessation. Change in self-reported symptoms of hypogonadism and other withdrawal symptoms will be compared with data from a group of men who ended AAS use temporarily without the medical intervention. The study may provide valuable clinical insights and may be used to inform the design of future intervention studies.

• Tungesvik, Helene Melsom; Bjørnebekk, Astrid Kristine & Hisdal, Jonny (2024). Impaired vascular function among young users of anabolic–androgenic steroids. Scientific Reports. 14(1). doi: 10.1038/s41598-024-70110-5. Full text in Research Archive Show summary

  Supraphysiological doses of anabolic–androgenic steroids (AAS) is popular among recreational weightlifters and bodybuilders due to the performance-enhancing properties but is also associated with adverse cardiovascular effects. The knowledge about how AAS affect the vasculature is limited, although results from previous studies suggest alterations in vasoreactivity and morphology. In the present study we investigate the association between long-term use of AAS and vascular function. Hundred and twenty-three males were included in the study, 56 of them current AAS users and 67 weightlifting controls. Vascular function was evaluated by carotid artery reactivity and flow-mediated dilation. AAS users had significantly reduced carotid artery reactivity (p < 0.001) and flow-mediated dilation (p < 0.001) compared to weightlifting controls. Results from the present study indicate that long-term use of AAS affect the cardiovascular system negatively, measured as reduced carotid artery reactivity and flow-mediated dilation. These findings could partly explain sudden cardiovascular events among young long-term users of AAS.

• Krispel, Thomas; Badeli, Vahid; Jafarinia, Alireza; Reinbacher-Köstinger, Alice; Tronstad, Christian & Ranftl, Sascha [Show all 11 contributors for this article] (2024). arterioscope.sim: Enabling Simulations of Blood Flow and Its Impact on Bioimpedance Signals. Bioengineering. 11(12). doi: 10.3390/bioengineering11121273. Full text in Research Archive Show summary

  Objectives: Early detection of cardiovascular diseases and their pre-existing conditions, arteriosclerosis and atherosclerosis, is crucial to increasing a patient’s chance of survival. While imaging technologies and invasive procedures provide a reliable diagnosis, they carry high costs and risks for patients. This study aims to explore impedance plethysmography (IPG) as a non-invasive and affordable alternative for diagnosis. Methods: To address the current lack of large-scale, high-quality impedance data, we introduce arterioscope.sim, a simulation platform that models arterial blood flow and computes the electrical conductivity of blood. The platform simulates bioimpedance measurements on specific body segments using patient-specific parameters. The study investigates how introducing arterial diseases into the simulation affects the bioimpedance signals. Results: The simulation results demonstrate that introducing atherosclerosis and arteriosclerosis leads to significant changes in the computed signals compared to simulations of healthy arteries. Furthermore, simulation of a patient-specific healthy artery strongly correlates with measured signals from a healthy volunteer. Conclusions and significance: arterioscope.sim effectively simulates bioimpedance signals in healthy and diseased arteries and highlights the potential of using these signals for early diagnosis of arterial diseases, offering a non-invasive and cost-effective alternative to traditional diagnostic methods.

• Nordén, Kristine Røren; Semb, Anne Grete; Dagfinrud, Hanne; Hisdal, Jonny; Sexton, Joseph & Fongen, Camilla [Show all 12 contributors for this article] (2024). Effect of high-intensity interval training in physiotherapy primary care for patients with inflammatory arthritis: The ExeHeart randomised controlled trial. RMD Open. 10(1). doi: 10.1136/rmdopen-2023-003440. Full text in Research Archive Show summary

  Objectives To assess the effect of high-intensity interval training (HIIT) delivered in physiotherapy primary care on the primary outcome of cardiorespiratory fitness (CRF) in patients with inflammatory arthritis (IA). Additionally, to explore the effects of HIIT on secondary outcomes, including cardiovascular disease (CVD) risk factors and disease activity. Methods Single-blinded randomised controlled trial with 60 patients randomly assigned to either a control group receiving usual care or an exercise group receiving usual care and 12 weeks of individualised HIIT at 90%–95% peak heart rate. Outcomes were assessed at baseline, 3 months and 6 months post baseline and included CRF measured as peak oxygen uptake (VO2peak), classic CVD risk factors, disease activity, anthropometry and patient- reported physical activity, pain, fatigue, disease impact and exercise beliefs and self-efficacy. Results Intention-to-treat analysis demonstrated a significant between-group difference in VO2peak at 3 months (2.5 mL/kg/min, 95% CI 0.9 to 4.0) and 6 months (2.6 mL/kg/min, 95% CI 0.8 to 4.3) in favour of the exercise group. A beneficial change in self-reported physical activity in favour of the exercise group was observed at 3 and 6 months. The HIIT intervention was well-tolerated with minimal adverse events and no apparent impact on disease activity. Differences in secondary outcomes related to CVD risk factors, disease impact, pain, fatigue and exercise beliefs and self-efficacy were generally small and non-significant. Conclusion After 12 weeks of supervised HIIT delivered in physiotherapy primary care, patients with IA demonstrated a favourable improvement in CRF, with sustained effects at 6-month follow-up.

• Lie, Sole Lindvåg; Hisdal, Jonny; Rehn, Marius & Høiseth, Lars Øivind (2024). Effect of systemic vascular resistance on the agreement between stroke volume by noninvasive pulse wave analysis and Doppler ultrasound in healthy volunteers. PLOS ONE. 19(5). doi: 10.1371/journal.pone.0302159. Full text in Research Archive Show summary

  Background Stroke volume can be estimated beat-to-beat and non-invasively by pulse wave analysis (PWA). However, its reliability has been questioned during marked alterations in systemic vascular resistance (SVR). We studied the effect of SVR on the agreement between stroke volume by PWA and Doppler ultrasound during reductions in stroke volume in healthy volunteers. Methods In a previous study we simultaneously measured stroke volume by PWA (SVPWA) and suprasternal Doppler ultrasound (SVUS). We exposed 16 healthy volunteers to lower body negative pressure (LBNP) to reduce stroke volume in combination with isometric hand grip to elevate SVR. LBNP was increased by 20 mmHg every 6 minutes from 0 to 80 mmHg, or until hemodynamic decompensation. The agreement between SVPWA and SVUS was examined using Bland-Altman analysis with mixed regression. Within-subject limits of agreement (LOA) was calculated from the residual standard deviation. SVRUS was calculated from SVUS. We allowed for a sloped bias line by introducing the mean of the methods and SVRUS as explanatory variables to examine whether the agreement was dependent on the magnitude of stroke volume and SVRUS. Results Bias ± limits of agreement (LOA) was 27.0 ± 30.1 mL. The within-subject LOA was ±11.1 mL. The within-subject percentage error was 14.6%. The difference between methods decreased with higher means of the methods (-0.15 mL/mL, confidence interval (CI): -0.19 to -0.11, P<0.001). The difference between methods increased with higher SVRUS (0.60 mL/mmHg × min × L-1, 95% CI: 0.48 to 0.72, P<0.001). Conclusion PWA overestimated stroke volume compared to Doppler ultrasound during reductions in stroke volume and elevated SVR in healthy volunteers. The agreement between SVPWA and SVUS decreased during increases in SVR. This is relevant in settings where a high level of reliability is required.

• Hove, Christine; Sæter, Frode Wirum; Stepanov, Alexey; Bøtker-Rasmussen, Kasper; Seeberg, Trine Margrethe & Westgaard, Espen [Show all 10 contributors for this article] (2024). A prototype photoplethysmography-based cuffless device shows promising results in tracking changes in blood pressure. Frontiers in Medical Technology. 6. doi: 10.3389/fmedt.2024.1464473. Full text in Research Archive Show summary

  Introduction: Non-invasive cuffless blood pressure devices have shown promising results in accurately estimating blood pressure when comparing measurements at rest. However, none of commercially available or prototype cuffless devices have yet been validated according to the appropriate standards. The aim of the present study was to bridge this gap and evaluate the ability of a prototype cuffless device, developed by Aidee Health AS, to track changes in blood pressure compared to a non-invasive, continuous blood pressure monitor (Human NIBP or Nexfin) in a laboratory set up. The performance was evaluated according to the metrics and statistical methodology described in the ISO 81060-3:2022 standard. However, the present study is not a validation study and thus the study was not conducted according to the ISO 81060-3:2022 protocol, e.g., non-invasive reference and distribution of age not fulfilled. Method: Data were sampled continuously, beat-to-beat, from both the cuffless and the reference device. The cuffless device was calibrated once using the reference BP measurement. Three different techniques (isometric exercise, mental stress, and cold pressor test) were used to induce blood pressure changes in 38 healthy adults. Results: The mean difference (standard deviation) was 0.3 (8.7) mmHg for systolic blood pressure, 0.04 (6.6) mmHg for diastolic blood pressure, and 0.8 (7.9) mmHg for mean arterial pressure, meeting the Accuracy requirement of ISO 81060-3:2022 (≤6.0 (10.0) mmHg). The corresponding results for the Stability criteria were 1.9 (9.2) mmHg, 2.9 (8.1) mmHg and 2.5 (9.5) mmHg. The acceptance criteria for the Change requirement were achieved for the 85th percentile of ≤50% error for diastolic blood pressure and mean arterial pressure but were higher than the limit for systolic blood pressure (56% vs. ≤50%) and for all parameters for the 50th percentile (32%–39% vs. ≤25%). Conclusions: The present study demonstrated that the cuffless device could track blood pressure changes in healthy adults across different activities and showed promising results in achieving the acceptance criteria from ISO 81060-3:2022.

• Nordén, Kristine Røren; Dagfinrud, Hanne; Semb, Anne Grete; Hisdal, Jonny; Metsios, George S. & Sexton, Joseph [Show all 9 contributors for this article] (2023). Criterion Validity and Responsiveness of Estimated Cardiorespiratory Fitness Models in Patients with Inflammatory Joint Disease. Journal of Clinical Medicine. 12(21). doi: 10.3390/jcm12216753. Full text in Research Archive Show summary

  Cardiorespiratory fitness (CRF) is an excellent marker of overall health. This study aimed to assess criterion validity and responsiveness of estimated CRF models (eCRF) in patients with inflammatory joint disease (IJD). CRF was measured directly as peak oxygen uptake (VO2peak) by a Cardiopulmonary Exercise Test (CPET), while one generic eCRF model (eCRFGEN) and two disease-specific eCRF models (eCRFALT and eCRFPGA) were used to estimate CRF at baseline and after 3 months in 55 Norwegian patients with IJD. Moderate correlations were observed between eCRFGEN, eCRFALT, eCRFPGA, and VO2peak at baseline (ICC 0.60, 0.64 and 0.62, respectively) and 3 months (ICC 0.62, 0.65 and 0.57, respectively). All eCRF models overestimated measured VO2peak, and there was large variability in agreement of individual measurements at baseline and at 3 months. Weak correlations were observed for responsiveness of eCRFGEN (ICC 0.39), eCRFALT (ICC 0.40) and eCRFPGA (ICC 0.39). Mean differences between change in eCRF models and change in VO2peak were small, but the wide limits of agreement exceeded the pre-defined clinically acceptable margins. The eCRF models possessed adequate ability to detect ≥3.5 mL/kg/min improvement in VO2peak. eCRF may suffice for group-level assessment, but caution is advised when applying eCRF to individual patients with IJD.

• Lie, Sole Lindvåg; Hisdal, Jonny; Rehn, Marius & Høiseth, Lars Øivind (2023). Hemodynamic effects of supplemental oxygen versus air in simulated blood loss in healthy volunteers: a randomized, controlled, double-blind, crossover trial. Intensive Care Medicine Experimental. 11(1). doi: 10.1186/s40635-023-00561-z. Full text in Research Archive Show summary

  Background Trauma patients frequently receive supplemental oxygen, but its hemodynamic effects in blood loss are poorly understood. We studied the effects of oxygen on the hemodynamic response and tolerance to simulated blood loss in healthy volunteers. Methods Fifteen healthy volunteers were exposed to simulated blood loss by lower body negative pressure (LBNP) on two separate visits at least 24 h apart. They were randomized to inhale 100% oxygen or medical air on visit 1, while inhaling the other on visit 2. To simulate progressive blood loss LBNP was increased every 3 min in levels of 10 mmHg from 0 to 80 mmHg or until hemodynamic decompensation. Oxygen and air were delivered on a reservoired face mask at 15 L/min. The effect of oxygen compared to air on the changes in cardiac output, stroke volume and middle cerebral artery blood velocity (MCAV) was examined with mixed regression to account for repeated measurements within subjects. The effect of oxygen compared to air on the tolerance to blood loss was measured as the time to hemodynamic decompensation in a shared frailty model. Cardiac output was the primary outcome variable. Results Oxygen had no statistically significant effect on the changes in cardiac output (0.031 L/min/LBNP level, 95% confidence interval (CI): − 0.015 to 0.077, P = 0.188), stroke volume (0.39 mL/LBNP level, 95% CI: − 0.39 to 1.2, P = 0.383), or MCAV (0.25 cm/s/LBNP level, 95% CI: − 0.11 to 0.61, P = 0.176). Four subjects exhibited hemodynamic decompensation when inhaling oxygen compared to 10 when inhaling air (proportional hazard ratio 0.24, 95% CI: 0.065 to 0.85, P = 0.027). Conclusions We found no effect of oxygen compared to air on the changes in cardiac output, stroke volume or MCAV during simulated blood loss in healthy volunteers. However, oxygen had a favorable effect on the tolerance to simulated blood loss with fewer hemodynamic decompensations. Our findings suggest that supplemental oxygen does not adversely affect the hemodynamic response to simulated blood loss. Trial registration This trial was registered in ClinicalTrials.gov (NCT05150418) December 9, 2021

• Mansoor, Saira Mauland; Rabben, Toril; Hisdal, Jonny & Jørgensen, Jørgen Joakim (2023). Eleven-Year Outcomes of a Screening Project for Abdominal Aortic Aneurysm (AAA) in 65-Year-Old Men. Vascular Health and Risk Management. ISSN 1176-6344. 19, p. 459–467. doi: 10.2147/VHRM.S412954. Full text in Research Archive Show summary

  Objective: Since 2011, the Department of Vascular Surgery at Oslo University Hospital has offered screening for abdominal aortic aneurysm (AAA) to 65-year-old men living in Oslo, Norway. The aim of this study was to evaluate the effect of the screening project on AAA-related mortality and rupture and repair rates in the screened population. Methods: This cohort study included men that participated in AAA screening at the Department of Vascular Surgery at Oslo University Hospital in the period May 2011 to September 2019. All men with screen-detected AAA (aortic diameter ≥ 30 mm) and subaneurysmal aortic dilatation (aortic diameter 25– 29 mm) were included. A stratified (1:1 with the subaneurysm group), randomized selection of men with normal aortic diameter (< 25 mm) upon screening was also included. The follow-up data on events (ruptures, repairs, and deaths) after screening were collected retrospectively from patient electronic medical records at Oslo University Hospital, the National Population Register and the Norwegian Cause of Death Registry (CoDR). Results: In total, 2048 men were included, with a median follow-up time of 7.1 years (IQR 3.8). Among men with screen-detected AAA, 0.6% died of AAA-related causes (0.9 AAA-related deaths per 1000 person-years). The rupture rate was 0.3% among men with screen-detected AAA or subaneurysmal aortic dilatation, giving an incidence of 0.5 ruptures per 1000 person-years. The overall repair rate in the AAA group was 20.6% (36.1 repairs per 1000 person-years) and 0.6% (0.9 repairs per 1000 person-years) in the subaneurysm group. Conclusion: In a population screened for AAA, the incidence of rupture and the AAA-related mortality was very low. Almost one-fifth of the participants with screen-detected AAA underwent elective repair, representing a group that might have presented with rupture if untreated. These results indicate that screening is valuable in preventing AAA rupture and AAA-related mortality.

• Sletten, Ole Jakob; Aalen, John; Smiseth, Otto Armin; Khan, Faraz Hameed; Fosså, Alexander & Kiserud, Cecilie E. [Show all 10 contributors for this article] (2023). Mental Stress Reduces Left Ventricular Strain: Can It Lead to Misinterpretation of Cancer Therapy–Related Cardiac Dysfunction? Journal of the American Society of Echocardiography. ISSN 0894-7317. doi: 10.1016/j.echo.2023.11.010. Full text in Research Archive
• Kyte, Karoline Holsen; Haakstad, Lene Annette Hagen; Hisdal, Jonny; Sunde, Andrine & Stensrud, Trine (2023). Bone health in Norwegian female elite runners: A cross-sectional, controlled study. BMJ Open sport & exercise medicine. 9(1). doi: 10.1136/bmjsem-2022-001472. Full text in Research Archive Show summary

  Objective: The primary objective was to compare bone mineral density (BMD) in Norwegian female elite long-distance runners with a control group of inactive females. Secondary objectives were to identify cases of low BMD, to compare the concentration of bone turnover markers, vitamin D and symptoms of low energy availability (LEA) between the groups, and to identify possible associations between BMD and selected variables. Methods: Fifteen runners and fifteen controls were included. Assessments included dual-energy X-ray absorptiometry measurement of BMD in the total body, lumbar spine and dual proximal femur. Blood samples included endocrine analyses and circulating bone turnover markers. The risk of LEA was assessed through a questionnaire. Results: Runners had higher Z-scores in the dual proximal femur (1.30 (0.20 to 1.80) vs 0.20 (−0.20 to 0.80), p<0.021) and total body (1.70 (1.20 to 2.30) vs 0.90 (0.80 to 1.00), p<0.001). The lumbar spine Z-score was similar between groups (0.10 (−0.70 to 0.60) vs −0.10(−0.50 to 0.50), p=0.983). Three runners had low BMD (Z-score <−1) in the lumbar spine. Vitamin D and bone turnover markers showed no differences between the groups. Forty-seven per cent of the runners were at risk of LEA. Dual proximal femur BMD showed a positive correlation to estradiol and a negative correlation to LEA symptoms in runners. Conclusion: Norwegian female elite runners had higher BMD Z-score in the dual proximal femur and total body compared with controls, while no difference was observed in the lumbar spine. The advantages of long-distance running on bone health seem to be site specific, and there is still a need for the prevention of LEA and menstrual disorders in this group.

• Høiseth, Lars Øivind; Fjose, Lars Olav; Hisdal, Jonny; Comelon, Marlin; Rosseland, Leiv Arne & Lenz, Harald (2023). Haemodynamic effects of methoxyflurane versus fentanyl and placebo in hypovolaemia: a randomised, double-blind crossover study in healthy volunteers. BJA Open. 7. doi: 10.1016/j.bjao.2023.100204. Full text in Research Archive Show summary

  Background: Methoxyflurane is approved for relief of moderate to severe pain in conscious adult trauma patients: it may be self-administrated and is well suited for use in austere environments. Trauma patients may sustain injuries causing occult haemorrhage compromising haemodynamic stability, and it is therefore important to elucidate whether methoxyflurane may adversely affect the haemodynamic response to hypovolaemia. Methods: In this randomised, double-blinded, placebo-controlled, three-period crossover study, inhaled methoxyflurane 3 ml, i.v. fentanyl 25 μg, and placebo were administered to 15 healthy volunteers exposed to experimental hypovolaemia in the lower body negative pressure model. The primary endpoint was the effect of treatment on changes in cardiac output, while secondary endpoints were changes in stroke volume and mean arterial pressure and time to haemodynamic decompensation during lower body negative pressure. Results: There were no statistically significant effects of treatment on the changes in cardiac output, stroke volume, or mean arterial pressure during lower body negative pressure. The time to decompensation was longer for methoxyflurane compared with fentanyl (hazard ratio 1.9; 95% confidence interval 0.4-3.4; P=0.010), whereas there was no significant difference to placebo (hazard ratio -1.3; 95% confidence interval -2.8 to 0.23; P=0.117). Conclusions: The present study does not indicate that methoxyflurane has significant adverse haemodynamic effects in conscious adults experiencing hypovolaemia. Clinical trial registration: ClinicalTrials.gov (NCT04641949) and EudraCT (2019-004144-29) https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004144-29/NO.

• Nordén, Kristine Røren; Semb, Anne Grete; Dagfinrud, Hanne; Hisdal, Jonny; Ødegård, Sigrid & Sexton, Joseph [Show all 11 contributors for this article] (2023). Associations between cardiovascular risk factors, disease activity and cardiorespiratory fitness in patients with inflammatory joint disease: a cross-sectional analysis. BMC sports science, medicine and rehabilitation. 15, p. 1–11. doi: 10.1186/s13102-023-00678-4. Full text in Research Archive Show summary

  Background Inflammatory joint diseases (IJD) are accompanied by an increased risk of cardiovascular disease (CVD). Cardiorespiratory fitness (CRF) is a modifiable CVD risk factor and low levels of CRF associate with an elevated CVD risk. This study aimed to investigate the associations between CVD risk factors, disease activity and CRF in patients with IJD and to explore differences between patients with normal versus low levels of CRF. Methods CRF was measured as peak oxygen uptake (VO2peak) with a cardiopulmonary exercise test. Participants were also evaluated for: Body composition, blood pressure, blood lipids, inflammatory markers and disease activity. Patient-reported use of cigarettes/snuff, medication, disease duration, pain, fatigue, CVD history, habitual physical activity and exercise beliefs and self-efficacy were collected by questionnaire. Cross-sectional associations between CVD risk factors, disease-related factors and CRF were analyzed by multiple linear regression. CRF was categorized to normal CRF (VO2peak ≥ 80%) or low CRF (VO2peak < 80%) according to age- and gender-stratified reference data. Differences in demographic, CVD and disease-related factors between patients with normal versus low CRF were explored. Results In 60 Norwegian patients with IJD [34 females, age 59 years (IQR: 52–63)], mean VO2peak was 30.2 (± 6.9) mL/kg/min, corresponding to 83% (± 18) of normative reference values. Age (coefficient: − 0.18 years, p = 0.01) and fat mass (coefficient: − 0.67 %, p < 0.001) were inversely associated with CRF, while physical activity index (coefficient: 0.13 points, p = 0.05) was positively associated with CRF (R2 = 0.66). There were no significant associations between CRF, classical CVD risk factors and disease-related variables. Compared to patients with low CRF (n = 30), patients with normal CRF (n = 30) had higher peak oxygen uptake (+ 9.4 mL/kg/min, p < 0.001), high-density lipoprotein cholesterol (+ 0.5 mmol L−1, p < 0.001), and exercise self-efficacy (+ 6.9, p < 0.01) as well as lower fat mass (− 8.7%, p < 0.001), resting heart rate (− 8.0 beats/min, p < 0.01) and triglycerides (− 0.5 mmol L−1, p < 0.01). Conclusions In this sample of IJD-patients, age, fatmass and physical activity level were associated with CRF. CRF was lower than reference values and patients with normal CRF presented with a more favorable health profile. There is a continued need for exercise interventions to improve CRF in patients with IJD. Trial registration: NCT04922840.

• Kyte, Karoline Holsen; Lunde, Cecilie & Hisdal, Jonny (2023). Post-Exercise Ankle–Brachial Index Is Reduced in Healthy, Young Individuals at a Level Indicating Peripheral Artery Disease. Clinics and Practice. 13(2), p. 529–536. doi: 10.3390/clinpract13020049. Full text in Research Archive Show summary

  In young patients referred for exercise-induced pain in the legs, false positive tests are a potential problem for the post-exercise ankle–brachial index (ABI) test when using the current American Heart Association guidelines for diagnosing peripheral artery disease (PAD). The present study aimed to investigate post-exercise ABI in healthy young people, and to explore whether the current diagnostic criteria for pathological ABI should be revised. Forty-eight volunteers (18–30 years) were included. Resting examinations included ABI and ultrasound of the external iliac artery. Post-exercise examinations after a treadmill load included ABI and ultrasound of the external iliac artery; after 0 min and after 3 min. A total of 60.5% of the participants had a post-exercise decrease in ABI &gt; 20%. A total of 6.5% showed a decrease in ankle systolic blood pressure &gt;30 mmHg. No significant association was observed between a change in blood flow in the external iliac artery and a reduction in ABI post-exercise. Analyses of the ultrasound recordings showed no turbulence in the external iliac artery. According to the results, a 20% decrease in ABI post-exercise seems to be a physiological condition present in young people. We support the need for a reassessment of the criteria for diagnosing PAD.

• Hagum, Cathrine Nyhus; Tønnessen, Espen; Hisdal, Jonny & Shalfawi, Shaher A. I. (2023). The effect of progressive and individualised sport-specific training on the prevalence of injury in football and handball student athletes: a randomised controlled trial. Frontiers in Sports and Active Living. 5, p. 1–11. doi: 10.3389/fspor.2023.1106404. Full text in Research Archive Show summary

  Objective: To evaluate the effectiveness of communication and coordination combined with designing a progressive and individualised sport-specific training program for reducing injury prevalence in youth female and male football and handball players transitioning to a sports academy high school. An additional aim was to investigate the characteristics of the reported injuries. Methods: Forty-two Norwegian athletes were randomised into an intervention or control group. Mean age, height, weight and BMI was 15.5 ± 0.5 years, 178.6 cm ± 6.3 cm, 71.3 ± 9.8 kg, 22.3 ± 2.7 BMI for the intervention group (IG) (n = 23), and 15.4 ± 0.5 years, 175.6 cm ± 6.6 cm, 67.1 ± 9.8 kg, 21.7 ± 2.4 BMI for the control group (CG) (n = 19). During the summer holiday, the intervention group received weekly progressive, individualised sport-specific training programs and weekly follow-up telephone calls from the researchers. All athletes completed a baseline questionnaire and a physical test battery. Training data and injuries were recorded prospectively for 22 weeks using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2). A two-way chi-square (χ2) test of independence was conducted to examine the relationship between groups and injury. Results: Average weekly prevalence of all injuries was 11% (95% CI: 8%–14%) in IG and 19% (95% CI: 13%–26%) in CG. Average weekly prevalence of substantial injuries was 7% (95% CI: 3%–10%) in IG and 10% (95% CI: 6%–13%) in CG. The between-group difference in injuries was significant: χ2 (1, N = 375) = 4.865, p = .031, φ = .114, with 1.8 times higher injury risk in CG vs. IG during the first 12 weeks after enrolment. Conclusions: For student athletes transitioning to a sports academy high school, progressive individualised, sport-specific training programs reduced the prevalence of all-complaint injuries following enrolment. Clubs and schools should prioritise time and resources to implement similar interventions in periods where student athletes have less supervision, such as the summer holidays, to facilitate an optimal transition to a sports academy high school.

• Tronstad, Christian; Amini, Maryam; Olesen, Eline; Qvigstad, Elisabeth; Pabst, Oliver & Martinsen, Tormod [Show all 11 contributors for this article] (2022). Diabetic foot assessment using skin impedance in a custom made sensor-sock. Journal of Electrical Bioimpedance. 13(1), p. 136–142. doi: 10.2478/joeb-2022-0019. Full text in Research Archive Show summary

  Abstract Diabetic peripheral neuropathy (DPN) may lead to several changes in the skin, and some of these may influence the skin impedance spectrum. In the present study we have developed a prototype solution for skin impedance spectroscopy at selected skin sites (big toe pulp, heel and toe ball) that was tested in a pilot study on five patients with DPN and five healthy controls. At the big toe, most of the controls had markedly lower impedance than the DPN group, especially in the range of 1-100 kHz. The separation between the groups seems to be weaker at the heel and weakest at the toeball. The results may indicate that monitoring of the skin impedance spectrum may be a method for detection of skin changes associated with DPN, encouraging further studies with the big toe sensor in particular.

• Kazmi, Syed Sajid Hussain; Safi, Natkai; Berge, Simen Tveten; Kazmi, Marryam; Sundhagen, Jon Otto & Hisdal, Jonny (2022). Laparoscopic Surgery for Median Arcuate Ligament Syndrome (MALS): A Prospective Cohort of 52 Patients. Vascular Health and Risk Management. ISSN 1176-6344. 18, p. 139–151. doi: 10.2147/VHRM.S350841. Full text in Research Archive Show summary

  Background: The selection of patients with MALS for surgical treatment depends upon the reliability of the symptom interpretation and the diagnostic work-up. We aimed to follow up the results of the laparoscopic decompression of the patients with MALS. Patients and Methods: In a single-center, 52 consecutive MALS patients were followed-up, prospectively, after transperitoneal laparoscopic decompression. MALS was diagnosed with a computed tomography angiography (CTA) verified stenosis, ≥ 50% of the celiac artery (CA), and with duplex ultrasound, a peak systolic velocity (PSV) ≥ 2.0 m/s. Postoperative, CTA, and duplex ultrasound were performed, and the patients were followed-up at 3, 6, 12 months, and yearly after that. Results: Mean age of the patients was 47 ± 21 years, and 65% were females. The patients had a mean weight loss of 8.4 ± 7.2 kg. Fifty-one patients had the laparoscopic operation with a mean operation time of 102 ± 28 minutes. Forty-seven patients (90%) achieved relief from the symptoms either completely (67%) or partially (23%) at 3– 6 months of follow-up. Significant improvement in postoperative PSV was found compared to the preoperative values, p< 0.001. Five patients (10%) with no immediate effect of the operation, but two of them became free from symptoms during the mean study follow-up of 2.4 ± 2 years. Five patients (10%) had operative complications, including one trocar injury to the liver, one pneumothorax, and three cases of bleeding from the branches of CA. Two patients died of cancer disease during the study period. Only two patients (4%) had symptoms relapse, both later treated successfully. Conclusion: Laparoscopic transperitoneal decompression provides most of the patients a persistent relief from MALS symptoms. Keywords: median arcuate ligament syndrome, postprandial pain, laparoscopy, mesenteric ischemia

• Melsom, Helene Støle; Heiestad, Christina Mathisen; Eftestøl, Einar; Torp, May-Kristin; Gundersen, Kristian & Bjørnebekk, Astrid [Show all 9 contributors for this article] (2022). Reduced arterial elasticity after anabolic–androgenic steroid use in young adult males and mice. Scientific Reports. 12(1). doi: 10.1038/s41598-022-14065-5. Full text in Research Archive Show summary

  Abstract High-doses of anabolic–androgenic steroids (AAS) is efficient for building muscle mass, but pose a risk of cardiovascular side effects. Little is known of the effect of AAS on vasculature, but previous findings suggest unfavorable alterations in vessel walls and vasoreactivity. Here, long-term effect of AAS on vascular function and morphology were examined in male weightlifters, and in a mimicking animal model. Arterial elasticity and morphology were tested with ultrasound, pulse wave velocity (PWV) and carotid intima media thickness (cIMT) in 56 current male AAS users, and 67 non-exposed weightlifting controls (WLC). Female mice were treated with testosterone for 14 days and echocardiography were applied to evaluate vascular function and morphology. Male AAS users had higher PWV (p = 0.044), reduced carotid artery compliance (p = 0.0005), and increased cIMT (p = 0.041) compared to WLC. Similar functional changes were found in the ascending aorta of mice after 7- (p = 0.043) and 14 days (p = 0.001) of testosterone treatment. This animal model can be used to map molecular mechanisms responsible for complications related to AAS misuse. Considering the age-independent stiffening of major arteries and the predictive power of an increase in PWV and cIMT, the long-term users of AAS are at increased risk of severe cardiovascular events.

• Tronstad, Christian; Pabst, Oliver; Amini, Maryam; Kleggetveit, Inge Petter; Elvebakk, Ole & Martinsen, Ørjan Grøttem [Show all 10 contributors for this article] (2022). Development of a prototype toe sensor for detection of diabetic peripheral small fiber neuropathy. Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). doi: 10.1109/EMBC48229.2022.9871101. Full text in Research Archive
• Melsom, Helene Støle; Randa, Anders; Hisdal, Jonny; Stang, Julie & Stensrud, Trine (2022). Prevalence of asthma among Norwegian elite athletes. Translational Sports Medicine (TSM). 2022, p. 1–10. doi: 10.1155/2022/3887471. Full text in Research Archive Show summary

  Objective. Asthma is a common problem among elite athletes and represents a health risk interfering with the athlete’s performance status. This study aimed to evaluate the asthma prevalence among Norwegian summer and winter elite athletes and asthma prevalence across sport categories. We also aimed to examine whether bronchial hyperresponsiveness (BHR), lung function, fraction of exhaled nitric oxide (FENO), and allergy status differed between asthmatic and non-asthmatic elite athletes. Methods. Norwegian athletes qualifying for the Beijing Olympic Summer Games 2008 (n = 80) and the Vancouver Olympic Winter Games 2010 (n = 55) were included. The athletes underwent clinical respiratory examination including lung function measurement, methacholine bronchial challenge for assessment of BHR, FENO, and skin prick testing. Asthma was diagnosed based on respiratory symptoms and clinical examination including objective measurements. Results. Asthma was more prevalent among winter athletes (50%) than summer athletes (20%). Thirty-three (52%) endurance athletes, 3 (6%) team sport athletes, and 7 (33%) technical sport athletes had medically diagnosed asthma. Significantly lower lung function (p<0.001) and higher prevalence of severe BHR (p<0.001) were found in asthmatic athletes compared with non-asthmatic athletes. Conclusion. Asthma is common among Norwegian elite athletes, with winter and endurance athletes showing the highest prevalence. Asthmatic athletes were characterized by lower lung function and more severe BHR compared with non-asthmatic counterparts. The high prevalence among winter and endurance athletes demonstrates a need for increased attention to prevent and reduce the prevalence of asthma among those athletes.

• Pettersen, Erik Mulder; Hoel, Henrik; Torp, Hans; Hisdal, Jonny & Seternes, Arne (2022). The Effect of 12-Week Treatment with Intermittent Negative Pressure on Blood Flow Velocity and Flowmotion, Measured with a Novel Doppler Device (Earlybird). Secondary Outcomes from a Randomized Sham-Controlled Trial in Patients with Peripheral Arterial Disease. Annals of Vascular Surgery. ISSN 0890-5096. 86, p. 144–157. doi: 10.1016/j.avsg.2022.04.025. Full text in Research Archive Show summary

  Background Treatment with intermittent negative pressure (INP) is proposed as an adjunct to standard care in patients with peripheral arterial disease (PAD). The aims of this study were to evaluate the applicability of a novel ultrasound Dopplerdevice (earlybird) to assess blood flow characteristics in patients with PAD during a treatment session with INP, and whether certain flowproperties could determine who could benefit from INP treatment. Methods Secondary outcomes of data from a randomized sham-controlled trial were explored. Patients were randomized to 12 weeks of treatment with 40 mm Hg or 10 mm Hg INP, for one hour twice daily. Earlybird blood flow velocity recordings were made before and after the 12-week treatmentperiod and consists of a 5-min recording in rest, 3-min during INP treatment and 5-min recording after ended INP test-treatment. Mean blood flow velocity (vmean), relative changes in flow and frequency spectrum by Fourier-transform of the respective bandwidths of endothelial, sympathetic, and myogenic functions, were analyzed for the different series of blood flow measurements. Results In total, 62 patients were eligible for analysis, where 32 patients were treated with 40 mm Hg INP. The acquired recordings were of good quality and were used for descriptive analyses of flow characteristics. An immediate increase in vmean during the negative pressure periods of the INP test-treatment was observed in the 40 mm Hg INP treatment group at both pre- and post-test. There was a significant difference between the treatment groups, with a difference between the medians of 13.7 (P < 0.001) at pre-test and 10.7 (P < 0.001) at posttest. This finding was confirmed with spectrum analysis by Fourier-transform of the bandwidth corresponding to INP treatment. The change in amplitude corresponding to myogenic function after 12-weeks of treatment, was significantly different in favor of the 40 mm Hg INP treatment group. We were not able to detect the specific flow characteristics indicating who would benefit INP-treatment. Conclusions Earlybird is an applicable tool for assessing blood flow velocity in patients with PAD. Analysis of the flow velocity recordings shows that INP induces an immediate increase in blood flow velocities during INP. The positive effects of INP may be attributed to recruitment of arterioles, and thereby, increasing blood flow. In these analyses, no flow characteristics were determined which could predict who would benefit INP treatment.

• Kazmi, Syed Sajid Hussain; Safi, Natkai; Berge, Simen Tveten; Kazmi, Marryam; Sundhagen, Jon Otto & Julien, Kari [Show all 10 contributors for this article] (2022). Plasma α-Glutathione S-Transferase in Patients with Chronic Mesenteric Ischemia and Median Arcuate Ligament Syndrome. Vascular Health and Risk Management. ISSN 1176-6344. 18, p. 567–574. doi: 10.2147/VHRM.S365625. Full text in Research Archive Show summary

  Background: Chronic mesenteric ischemia (CMI) due to either atherosclerosis of the mesenteric arteries or median arcuate ligament syndrome (MALS) is an underdiagnosed entity. The etiology of MALS and its existence have been debated and questioned. We aimed to identify plasma biomarkers indicating mesenteric ischemia in patients with CMI and MALS. Methods: Plasma α-glutathione S-transferase (α-GST), intestinal fatty acid-binding protein (I-FABP), citrulline, and ischemia modified albumin (IMA) were analyzed in fifty-eight patients with CMI (Group A, n=44) and MALS (Group B, n=14) before and after revascularization. The plasma levels of these potential biomarkers were compared with those of healthy individuals (Group C, n=16). Group comparison was performed with the Mann–Whitney U-test. Cross-tabulation and its derivatives were obtained. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were calculated. Results: Plasma levels of α-GST were significantly raised in the patients with CMI (7.8 ng/mL, p< 0.001) and MALS (8.4 ng/mL, p< 0.001), as compared with the control Group C (3.3 ng/mL). The threshold for normal median plasma α-GST levels of 4 ng/mL yielded a sensitivity of 93% and 86%, specificity of 86% and 88%, respectively, for the diagnosis of CMI due to atherosclerosis and MALS. AUC of ROC curves was 0.96 (p< 0.0001) for CMI and 0.85 (p< 0.002) for MALS. The patient groups did not differ from the healthy controls in any other biomarkers. Conclusion: Plasma α-GST levels are elevated in CMI and MALS patients. Elevated plasma levels of α-GST suggest ischemia as the etiology of MALS.

• Aune, Susanne Kristine; Bonnevie-Svendsen, Martin; Nyborg, Christoffer; Trøseid, Marius; Seljeflot, Ingebjørg & Hisdal, Jonny [Show all 7 contributors for this article] (2022). Gut Leakage and Cardiac Biomarkers after Prolonged Strenuous Exercise. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 54(9), p. 1476–1482. doi: 10.1249/MSS.0000000000002948. Full text in Research Archive
• Kyte, Karoline Holsen; Stensrud, Trine; Berg, Tore Julsrud; Seljeflot, Ingebjørg & Hisdal, Jonny (2022). Vascular Function in Norwegian Female Elite Runners: A Cross-Sectional, Controlled Study. Sports. 10(3). doi: 10.3390/sports10030037. Full text in Research Archive Show summary

  In general, aerobic exercise has a positive impact on the vascular system, but the syndrome of relative energy-deficiency in sports (RED-S) makes this impact less clear for the athlete. The present cross-sectional controlled study aimed to investigate the vascular function in female elite long-distance runners, compared to inactive women. Sixteen female elite long-distance runners and seventeen healthy controls were recruited. Assessments of vascular function and morphology included endothelial function, evaluated by flow-mediated dilatation (FMD), vascular stiffness, evaluated with pulse wave velocity (PWV), carotid artery reactivity (CAR %), and carotid intima-media thickness (cIMT). Blood samples included hormone analyses, metabolic parameters, lipids, and biomarkers reflecting endothelial activation. RED-S risk was assessed through the low energy availability in female questionnaire (LEAF-Q), and body composition was measured by dual-energy X-ray absorptiometry (DXA). We found no significant differences in brachial FMD, PWV, CAR %, cIMT, or biomarkers reflecting endothelial activation between the two groups. Forty-four percent of the runners had a LEAF-Q score consistent with being at risk of RED-S. Runners showed significantly higher HDL-cholesterol and insulin sensitivity compared to controls. In conclusion, Norwegian female elite runners had an as good vascular function and morphology as inactive women of the same age.

• Safi, Natkai; Ånonsen, Kim Vidar; Berge, Simen Tveten; Medhus, Asle Wilhelm; Sundhagen, Jon Otto & Hisdal, Jonny [Show all 7 contributors for this article] (2022). Early Identification of Chronic Mesenteric Ischemia with Endoscopic Duplex Ultrasound. Vascular Health and Risk Management. ISSN 1176-6344. p. 233–243. doi: 10.2147/VHRM.S358570. Full text in Research Archive Show summary

  Introduction: Due to diagnostic delay, chronic mesenteric ischemia (CMI) is underdiagnosed. We assumed that the patients suspected of CMI of the atherosclerotic origin or median arcuate ligament syndrome (MALS) could be identified earlier with endoscopic duplex ultrasound (E-DUS). Patients and Methods: Fifty CMI patients with CTA-verified stenosis of either ≥ 50% and ≥ 70% of celiac artery (CA) and superior mesenteric artery (SMA) were examined with E-DUS and transabdominal duplex ultrasound (TA-DUS). Peak systolic velocities (PSV) of ≥ 200cm/s and ≥ 275cm/s for CA and SMA, respectively, were compared with CTA. Subgroup analysis was performed for the patients with (n=21) and without (n=29) prior revascularization treatment of CMI. The diagnostic ability of E-DUS and TA-DUS was tested with crosstabulation analysis. Receiver operating characteristics (ROC) curve analysis was performed, and the area under the curve (AUC) was calculated to investigate the test accuracy. Results: In the patients with ≥ 70% stenosis, E-DUS had higher sensitivity than TA-DUS (91% vs 81% for CA and 100% vs 92% for SMA). AUC for SMA ≥ 70% in E-DUS was 0.75 and with TA-DUS 0.68. The sensitivity of E-DUS for CTA-verified stenosis ≥ 70% for CA was 100% in the patients without prior treatment. E-DUS demonstrated higher sensitivity than TA-DUS for both arteries with stenosis ≥ 50% and ≥ 70% in the treatment-naive patients. Conclusion: E-DUS is equally valid as TA-DUS for the investigation of CMI patients and should be used as an initial diagnostic tool for patients suspected of CMI.

• Djupedal, Håvard; Nøstdal, Torkjell; Hisdal, Jonny; Landsverk, Svein A. & Høiseth, Lars Øivind (2022). Effects of experimental hypovolemia and pain on pre-ejection period and pulse transit time in healthy volunteers. Physiological Reports. 10(12), p. 1–10. doi: 10.14814/phy2.15355. Full text in Research Archive Show summary

  Trauma patients may suffer significant blood loss, and noninvasive methods to diagnose hypovolemia in these patients are needed. Physiologic effects of hypovolemia, aiming to maintain blood pressure, are largely mediated by increased sympathetic nervous activity. Trauma patients may however experience pain, which also increases sympathetic nervous activity, potentially confounding measures of hypovolemia. Elucidating the common and separate effects of the two stimuli on diagnostic methods is therefore important. Lower body negative pressure (LBNP) and cold pressor test (CPT) are experimental models of central hypovolemia and pain, respectively. In the present analysis, we explored the effects of LBNP and CPT on pre-ejection period and pulse transit time, aiming to further elucidate the potential use of these variables in diagnosing hypovolemia in trauma patients. We exposed healthy volunteers to four experimental sequences with hypovolemia (LBNP 60 mmHg) or normovolemia (LBNP 0 mmHg) and pain (CPT) or no pain (sham) in a 2 × 2 fashion. We calculated pre-ejection period and pulse transit time from ECG and ascending aortic blood velocity (suprasternal Doppler) and continuous noninvasive arterial pressure waveform (volume-clamp method). Fourteen subjects were available for the current analyses. This experimental study found that pre-ejection period increased with hypovolemia and remained unaltered with pain. Pulse transit time was reduced by pain and increased with hypovolemia. Thus, the direction of change in pulse transit time has the potential to distinguish hypovolemia and pain.

• Nordén, Kristine Røren; Dagfinrud, Hanne; Semb, Anne Grete; Hisdal, Jonny; Viktil, Kirsten Kilvik & Sexton, Joseph [Show all 11 contributors for this article] (2022). Effect of high-intensity exercise on cardiorespiratory fitness, cardiovascular disease risk and disease activity in patients with inflammatory joint disease: Protocol for the ExeHeart randomised controlled trial. BMJ Open. 12(2). doi: 10.1136/bmjopen-2021-058634. Full text in Research Archive Show summary

  Introduction Inflammatory joint disease (IJD) is associated with increased risk of cardiovascular disease (CVD) fostered by systemic inflammation and a high prevalence of CVD risk factors. Cardiorespiratory fitness (CRF) is an important health parameter and CRF-measures are advocated in routine health evaluations. CRF associates with CVD risk, and exercise modalities such as high intensity interval training (HIIT) can increase CRF and mitigate CVD risk factors. In IJD, exercise is rarely used in CVD risk management and the cardioprotective effect of HIIT is unclear. Furthermore, the clinical applicability of HIIT to primary care settings is largely unknown and warrants investigation. The primary aim is to assess the effect of a HIIT programme on CRF in patients with IJD. Second, we will evaluate the effect of HIIT on CVD risk and disease activity in patients with IJD, feasibility of HIIT in primary care and validity of non-exercise algorithms to detect change in CRF. Methods and analysis ExeHeart is a single-blinded, randomised controlled trial. Sixty patients with IJD will be recruited from the Preventive Cardio-Rheuma clinic at Diakonhjemmet Hospital, Norway. Patients will be assigned to receive standard care (relevant lifestyle advice and cardio-preventive medication) or standard care plus a 12-week HIIT intervention by physiotherapists in primary care. HIIT sessions will be prescribed at 90%–95% of peak heart rate. Outcomes include CRF (primary outcome), CVD risk factors, anthropometric measures, disease activity and patient-reported outcomes related to pain, fatigue, disease, physical activity and exercise and will be assessed at baseline, 3 months (primary endpoint) and 6 months postbaseline. Ethics and dissemination Ethical approval has been obtained from the Regional Committee for Medical and Health Research Ethics (201227). Participants are required to sign a written informed consent form. Results will be discussed with patient representatives, submitted to peer-reviewed journals and presented at relevant platforms. Trial registration number NCT04922840.

• Hoel, Henrik; Pettersen, Erik Mulder; Høiseth, Lars Øivind; Mathiesen, Iacob; Seternes, Arne & Hisdal, Jonny (2021). Lower Extremity Intermittent Negative Pressure for Intermittent Claudication. Follow-Up after 24 Weeks of Treatment. Annals of Vascular Surgery. ISSN 0890-5096. 75, p. 253–258. doi: 10.1016/j.avsg.2021.03.016. Full text in Research Archive Show summary

  Background Treatment with lower extremity intermittent negative pressure (INP) of -40 mm Hg for one hour twice daily for 12 weeks, increases walking capacity in patients with intermittent claudication (IC). However, the effects of INP treatment beyond 12 weeks have not been elucidated. The aim of the present study was to investigate the clinical effects of INP treatment after 24 weeks in patients with IC. Methods This was a follow-up study after a randomized sham-controlled trial, where patients randomized to the active treatment group were offered to continue treatment for 12 additional weeks (24 weeks in total). Treatment with -40 mm Hg INP was applied in a pressure chamber sealed around the lower leg, and the patients were instructed to treat themselves at home one hour in the morning and one hour in the evening. Pain free walking distance (PWD), maximal walking distance (MWD), resting ankle-brachial index (ABI) and post exercise ABI were measured at baseline, after 12 and 24 weeks. Results Ten out of 32 patients (31%) from the active treatment group in the initial trial were included in this follow-up study. At baseline, PWD was (mean ±SD) 151 ± 91 m and MWD was 362 ±159 m. There was a significant increase in both PWD and MWD after 24 weeks of treatment, compared to baseline (ANOVA; P= 0.006 and P= 0.012, respectively). Post hoc tests revealed that PWD increased significantly from baseline to 12 weeks (mean 81 m; 95% CI [6, 156]; P = 0.032), and that MWD increased significantly from 12 to 24 weeks (mean 145 m; 95% CI [22, 268]; P = 0.018). There were no significant changes in resting ABI or post exercise ABI during the 24-week treatment period (ANOVA; P= 0.157 and P= 0.450, respectively). Conclusion Both PWD and MWD improved after treatment with – 40 mm Hg INP for one hour twice daily for 24 weeks, compared to baseline. The main improvement in PWD occurred during the first 12 weeks of treatment, whereas the main improvement in MWD occurred between 12 and 24 weeks of treatment.

• Hoel, Henrik; Pettersen, Erik Mulder; Høiseth, Lars Øivind; Mathiesen, Iacob; Seternes, Arne & Seljeflot, Ingebjørg [Show all 7 contributors for this article] (2021). Effects of intermittent negative pressure treatment on circulating vascular biomarkers in patients with intermittent claudication. Vascular Medicine. ISSN 1358-863X. 26(5), p. 489–496. doi: 10.1177/1358863X211007933. Full text in Research Archive Show summary

  The aim of this study was to investigate the effects of lower extremity intermittent negative pressure (INP) treatment for 1 hour twice daily for 12 weeks, on circulating vascular biomarkers in patients with intermittent claudication. Patients were randomized to treatment with –40 mmHg INP (treatment group), or –10 mmHg INP (sham control group). Venous blood samples were collected at baseline and after 12 weeks, and concentrations of vascular adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), E-selectin, P-selectin, von Willebrand factor (vWF), l-arginine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) were analyzed. A larger proportion of the patients in the treatment group (25/31) had a reduction in vWF levels after 12 weeks, compared to the sham control group (17/30) (p = 0.043). Within the treatment group there was a significant mean (SEM) reduction in the concentration of vWF of –11% (4) (p = 0.019), whereas there was no significant change in the levels of vWF in the sham control group (1% (6); p = 0.85). There were no significant differences in the change of any of the biomarker levels between the groups after 12 weeks of treatment. In conclusion, there were no differences in the change of the circulating levels of the measured biomarkers between the treatment group and the sham control group after 12 weeks of INP treatment. However, the observed changes in vWF might indicate a beneficial effect of INP treatment on endothelial activation and endothelial injury. Clinicaltrials.gov Identifier: NCT03640676

• Konstantin, Friedrich; Rollefstad, Silvia Christin Hellerud; Ikdahl, Eirik; Wibetoe, Grunde; Sexton, Joseph & Hisdal, Jonny [Show all 7 contributors for this article] (2021). Degree of arterial stiffness is comparable across inflammatory joint disease entities. Scandinavian Journal of Rheumatology. ISSN 0300-9742. doi: 10.1080/03009742.2021.1920169. Full text in Research Archive Show summary

  Objectives: Inflammatory joint disease (IJD) is associated with an increased risk of developing cardiovascular disease (CVD). Arterial stiffness is both a risk factor and a surrogate marker for CVD. This study aims to compare arterial stiffness across patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis, and, by extension, to explore the relationship between arterial stiffness and the estimated CVD risk by the Systematic COronary Risk Evaluation (SCORE) algorithm. Method: During the study period, from April 2017 to June 2018, 196 patients with IJD visited the Preventive Cardio-Rheuma Clinic in Oslo, Norway. A CVD risk stratification was performed, including the assessment of traditional risk factors and the measurement of arterial stiffness. Results: Thirty-six patients (18.4%) had elevated aortic pulse wave velocity (aPWV) (≥ 10 m/s). After adjustment for age and heart rate, arterial stiffness was comparable across the IJD entities (p = 0.69). Associated factors, revealed by regression analysis, were age, blood pressure, heart rate, presence of carotid plaques, establis hed CVD, non-steroidal anti-inflammatory drugs, and statin use. Furthermore, aPWV was positively correlated with estimated CVD risk (r = 0.7, p < 0.001) and patients with a very high predicted CVD risk (SCORE ≥ 10%) had significantly higher aPWV than patients at lower CVD risk (9.2 vs 7.5 m/s, p < 0.001). Conclusion: The degree of arterial stiffness was comparable across the IJD entities and was highly associated with the estimated CVD risk. Our findings support the need for an increased focus on prevention of CVD in all patients with IJD.

• Lie, Sole Lindvåg; Hisdal, Jonny & Høiseth, Lars Øivind (2021). Cerebral blood flow velocity during simultaneous changes in mean arterial pressure and cardiac output in healthy volunteers. European Journal of Applied Physiology. ISSN 1439-6319. p. 1–11. doi: 10.1007/s00421-021-04693-6. Full text in Research Archive Show summary

  Abstract Purpose Cerebral blood flow (CBF) needs to be precisely controlled to maintain brain functions. While previously believed to be autoregulated and near constant over a wide blood pressure range, CBF is now understood as more pressure passive. However, there are still questions regarding the integrated nature of CBF regulation and more specifically the role of cardiac output. Our aim was, therefore, to explore the effects of MAP and cardiac output on CBF in a combined model of reduced preload and increased afterload. Method 16 healthy volunteers were exposed to combinations of different levels of simultaneous lower body negative pressure and isometric hand grip. We measured blood velocity in the middle cerebral artery (MCAV) and internal carotid artery (ICAV) by Doppler ultrasound, and cerebral oxygen saturation (ScO 2 ) by near-infrared spectroscopy, as surrogates for CBF. The effect of changes in MAP and cardiac output on CBF was estimated with mixed multiple regression. Result Both MAP and cardiac output had independent effects on MCAV, ICAV and ScO 2 . For ICAV and ScO 2 there was also a statistically significant interaction effect between MAP and cardiac output. The estimated effect of a change of 10 mmHg in MAP on MCAV was 3.11 cm/s (95% CI 2.51–3.71, P  &lt; 0.001), and the effect of a change of 1 L/min in cardiac output was 3.41 cm/s (95% CI 2.82–4.00, P  &lt; 0.001). Conclusion The present study indicates that during reductions in cardiac output, both MAP and cardiac output have independent effects on CBF.

• Nyborg, Christoffer; Bonnevie-Svendsen, Martin; Melsom, Helene Støle; Melau, Jørgen; Seljeflot, Ingebjørg & Hisdal, Jonny (2021). Reduced L-Arginine and L-Arginine-ADMA-Ratio, and Increased SDMA after Norseman Xtreme Triathlon. Sports. 9(9). doi: 10.3390/sports9090120. Full text in Research Archive Show summary

  Endothelial vasodilatory function is dependent on the NO synthesis from L-arginine by endothelial NO-synthetase (eNOS). eNOS can be inhibited by asymmetric dimethylarginine (ADMA) by competitive inhibition on the binding site, and symmetric dimethylarginine (SDMA) can reduce the L-arginine availability intracellularly through competing for transport over the cellular membrane. To study the NO synthesis after prolonged exercise, we assessed circulatory L-arginine, the L-arginine/ADMA ratio, and SDMA before, after, and on the day after the Norseman Xtreme triathlon, an Ironman distance triathlon. We found significantly reduced levels of L-arginine and the L-arginine/ADMA ratio and increased levels of SDMA after the race (all p < 0.05). L-arginine rose toward baseline levels the day after the race, but ADMA increased beyond baseline levels, and SDMA remained above baseline the day after the race. The reduced levels of L-arginine and the L-arginine/ADMA ratio, and increased SDMA, after the race indicate a state of reduced capability of NO production. Increased levels of ADMA and SDMA, and reduced L-arginine/ADMA ratio, as seen the day after the race, are known risk markers of atherosclerosis and warrant further studies.

• Nyborg, Christoffer; Melsom, Helene Støle; Bonnevie-Svendsen, Martin; Melau, Jørgen; Seljeflot, Ingebjørg & Hisdal, Jonny (2021). Transient reduction of fmd-response and l-arginine accompanied by increased levels of e-selectin, vcam, and icam after prolonged strenuous exercise. Sports. 9(6), p. 1–10. doi: 10.3390/sports9060086. Full text in Research Archive Show summary

  We assessed endothelial function by flow-mediated dilatation (FMD), levels of the NO-precursor L-arginine, and markers of endothelial inflammation before, at the finish line, and one week after the Norseman Xtreme triathlon. The race is an Ironman distance triathlon with a total elevation of 5200 m. Nine male participants were included. They completed the race in 14.5 (13.4–15.3) h. FMD was significantly reduced to 3.1 (2.1–5.0)% dilatation compared to 8.7 (8.2–9.3)% dilatation before the race (p < 0.05) and was normalized one week after the race. L-arginine showed significantly reduced levels at the finish line (p < 0.05) but was normalized one week after the race. Markers of endothelial inflammation E-Selectin, VCAM-1, and ICAM-1 all showed a pattern with increased values at the finish line compared to before the race (all p < 0.05), with normalization one week after the race. In conclusion, we found acutely reduced FMD with reduced L-arginine levels and increased E-Selectin, VCAM-1, and ICAM-1 immediately after the Norseman Xtreme triathlon. Our findings indicate a transient reduced endothelial function, measured by the FMD-response, after prolonged strenuous exercise that could be explained by reduced NO-precursor L-arginine levels and increased endothelial inflammation.

• Høiseth, Lars Øivind; Melau, Jørgen; Bonnevie-Svendsen, Martin; Nyborg, Christoffer; Eijsvogels, Thijs M. H. & Hisdal, Jonny (2021). Core temperature during cold-water triathlon swimming. Sports. 9(6), p. 1–7. doi: 10.3390/sports9060087. Full text in Research Archive Show summary

  Triathlon and other endurance races have grown in popularity. Although participants are generally fit and presumably healthy, there is measurable morbidity and mortality associated with participation. In triathlon, most deaths occur during the swim leg, and more insight into risk factors, such as hypothermia, is warranted. In this study, we measured the core temperature of 51 participants who ingested temperature sensor capsules before the swim leg of a full-distance triathlon. The water temperature was 14.4–16.4 °C, and the subjects wore wetsuits. One subject with a low body mass index and a long swim time experienced hypothermia (<35 °C). Among the remaining subjects, we found no association between core temperature and swim time, body mass index, or sex. To conclude, the present study indicates that during the swim leg of a full-distance triathlon in water temperatures ≈ 15–16 °C, subjects with a low body mass index and long swim times may be at risk of hypothermia even when wearing wetsuits.

• Pettersen, Erik Mulder; Avdal, Jørgen; Fiorentini, Stefano; Salvesen, Øyvind; Hisdal, Jonny & Torp, Hans [Show all 7 contributors for this article] (2021). Validation of a novel ultrasound Doppler monitoring device (earlybird) for measurements of volume flow rate in arteriovenous fistulas for hemodialysis. Journal of Vascular Access. ISSN 1129-7298. p. 1–9. doi: 10.1177/11297298211060960. Full text in Research Archive Show summary

  Background: Controversy exists regarding surveillance of arteriovenous fistulas for hemodialysis to increase patency. A significant reduction in volume flow rate (VFR) should lead to diagnostic evaluation and eventually intervention. Several methods are available for VFR measurements, but all of them are associated with low reproducibility. VFR trend analysis is suggested as an improved solution. It is therefore a need to find user-friendly, cost and time-effective modalities. We present a novel Doppler ultrasound device (earlybird) which could bridge this gap. It includes an easy-to-use and light-weight single element transducer. Methods: In an experimental and clinical setting, we compared earlybird to duplex ultrasound to assess VFR. In a closed circuit of blood-mimicking fluid, 36 paired calculations of calibrated, duplex ultrasound and earlybird VFR was measured. In addition, 23 paired recordings of duplex ultrasound and earlybird VFR was measured in 16 patients with underarm arteriovenous fistulas. Pearson correlation, intraclass correlation coefficient, root-mean-square and Bland-Altman plots were analyzed. Results: Strong correlation (r = 0.991, p < 0.001), and excellent level of agreement (ICC = 0.970 (95% CI 0.932 - 0.985), p < 0.001) between earlybird and the calibrated VFR was found in the experimental setup. This was confirmed in the clinical setting, with a strong correlation (r = 0.781, p < 0.001) and moderate to good level of agreement (ICC = 0.750 (95% CI 0.502–0.885), p < 0.001) between earlybird and duplex ultrasound VFR measured at the arteriovenous fistulas outflow veins. In the Bland-Altman plot-analysis for the experimental setup, we found smaller limits of agreement, a smaller consistent and proportional bias, as well as greater accuracy of earlybird than DUS when compared to the calibrated VFR. Conclusion: Earlybird is a feasible tool for VFR measurements and could be a future promising device for easy assessment and surveillance of AVF for hemodialysis.

• Wiegerinck, Anouk; Thomsen, Andreas; Hisdal, Jonny; Kalvøy, Håvard & Tronstad, Christian (2021). Electrical impedance plethysmography versus tonometry to measure the pulse wave velocity in peripheral arteries in young healthy volunteers: a pilot study. Journal of Electrical Bioimpedance. 12(1), p. 169–177. doi: 10.2478/joeb-2021-0020. Full text in Research Archive Show summary

  Abstract The leading cause of health loss and deaths worldwide are cardiovascular diseases. A predictor of cardiovascular diseases and events is the arterial stiffness. The pulse wave velocity (PWV) can be used to estimate arterial stiffness non-invasively. The tonometer is considered as the gold standard for measuring PWV. This approach requires manual probe fixation above the artery and depends on the skills of the operator. Electrical impedance plethysmography (IPG) is an interesting alternative using skin surface sensing electrodes, that is miniaturizable, cost-effective and allows measurement of deeper arteries. The aim of this pilot study was to explore if IPG can be a suitable technique to measure pulse wave velocity in legs as an alternative for the tonometer technique. The PWV was estimated by differences in the ECG-gated pulse arrival times (PAT) at the a. femoralis, a. popliteal, a. tibialis dorsalis and a. dorsalis pedis in nine healthy young adults using IPG and the SphygmoCor tonometer as a reference. The estimated PWV results from bioimpedance and the tonometer were fairly in agreement, and the beat-to-beat variability in PAT was similar. This pilot study indicates that the use of IPG may be a good alternative for estimating PWV in the legs.

• Hoel, Henrik; Pettersen, Erik Mulder; Høiseth, Lars Øivind; Mathiesen, Iacob; Seternes, Arne & Hisdal, Jonny (2021). A randomized controlled trial of treatment with intermittent negative pressure for intermittent claudication. Journal of Vascular Surgery. ISSN 0741-5214. 73(5), p. 1750–1758.e1. doi: 10.1016/j.jvs.2020.10.024. Full text in Research Archive Show summary

  Objective: We investigated the effects of lower extremity intermittent negative pressure (INP) treatment for 1 hour two times daily for 12 weeks on the walking distance of patients with intermittent claudication (IC). Methods: Patients with IC were randomized to treatment with 40 mm Hg INP (treatment group) or 10 mm Hg INP (sham control group). Pain-free walking distance (PWD) and maximal walking distance (MWD) on a treadmill, resting and postexercise ankle-brachial index, resting and postischemic blood flow (plethysmography), and quality of life (EQ-5D-5L and Vascuqol-6) were measured at baseline and after 12 weeks of treatment. Results: A total of 72 patients were randomized, and 63 had data available for the intention-to-treat analyses. The between-group comparisons showed a significant change in the PWD, favoring the treatment group over the sham control group (estimated treatment effect, 50 m; 95% confidence interval [CI], 11-89; P ¼ .014). The PWD had increased by 68 m (P < .001) in the treatment group and 18 m (P ¼ .064) in the sham control group. No significant difference was found in the change in the MWD between the two groups (estimated treatment effect, 42 m; 95% CI, 14 to 97; P ¼ .139). The MWD had increased by 62 m (P ¼ .006) in the treatment group and 20 m (P ¼ .265) in the sham control group. For patients with a baseline PWD of <200 m (n ¼ 56), significant changes had occurred in both PWD and MWD between the two groups, favoring the treatment group (estimated treatment effect, 42 m; 95% CI, 2-83; P ¼ .042; and estimated treatment effect, 62 m; 95% CI, 5-118; P ¼ .032; respectively). Both overall and for the group of patients with a PWD <200 m, no significant differences were found in the changes in the resting and postexercise ankle-brachial index, resting and postischemic blood flow, or quality of life parameters between the two groups. Conclusions: Treatment with 40 mm Hg INP increased the PWD compared with sham treatment in patients with IC. For the patients with a baseline PWD of <200 m, an increase was found in both PWD and MWD compared with sham treatment. (J Vasc Surg 2021;73:1750-8.)

• Melau, Jørgen; Hisdal, Jonny & Solberg, Paul Andre (2021). Impact of a 10,000-m Cold-Water Swim on Norwegian Naval Special Forces Recruits. Journal of Special Operations Medicine. ISSN 1553-9768. 21(3), p. 55–59. doi: 10.55460/QE23-511P. Full text in Research Archive
• Johnsen, Lydia; Hisdal, Jonny; Jonung, Torbjörn; Braaten, Audun Ole & Pedersen, Gustav (2021). Three-dimensional ultrasound volume and conventional ultrasound diameter changes are equally good markers of endoleak in follow-up after endovascular aneurysm repair. Journal of Vascular Surgery. ISSN 0741-5214. doi: 10.1016/j.jvs.2021.08.103. Full text in Research Archive
• Illidi, Camilla Rønn; Stang, Julie; Melau, Jørgen; Hisdal, Jonny & Stensrud, Trine (2021). Does Cold-Water Endurance Swimming Affect Pulmonary Function in Healthy Adults? Sports. 9(1), p. 1–12. doi: 10.3390/sports9010007. Full text in Research Archive Show summary

  The acute effects of cold-water endurance swimming on the respiratory system have received little attention. We investigated pulmonary responses to cold-water endurance swimming in healthy recreational triathletes. Pulmonary function, alveolar diffusing capacity (DLCO), fractional exhaled nitric oxide (FENO) and arterial oxygen saturation by pulse oximetry (SpO2) were assessed in 19 healthy adults one hour before and 2.5 h after a cold-water (mean ± SD, 10 ± 0.9 °C) swim trial (62 ± 27 min). In addition, 12 out of the 19 participants measured pulmonary function, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) 3, 10, 20 and 45 min post-swim by maximal expiratory flow volume loops and DLCO by the single breath technique. FVC and FEV1 were significantly reduced 3 min post-swim (p = 0.02) (p = 0.04), respectively, and five of 12 participants (42%) experienced exercise-induced bronchoconstriction (EIB), defined as a ≥ 10% drop in FEV1. No significant changes were observed in pulmonary function 2.5 h post-swim. However, mean FENO and DLCO were significantly reduced by 7.1% and 8.1% (p = 0.01) and (p < 0.001), respectively, 2.5 h post-swim, accompanied by a 2.5% drop (p < 0.001) in SpO2. The absolute change in DLCO correlated significantly with the absolute decline in core temperature (r = 0.52; p = 0.02). Conclusion: Cold-water endurance swimming may affect the lungs in healthy recreational triathletes lasting up to 2.5 h post-swim. Some individuals appear to be more susceptible to pulmonary impairments than others, although these mechanisms need to be studied further.

• Stens, Niels Anton; Hisdal, Jonny; Bakke, Espen; Kaur, Narinder; Sharma, Archana & Stranden, Einar [Show all 8 contributors for this article] (2020). Factors mediating the pressor response to isometric muscle contraction: An experimental study in healthy volunteers during lower body negative pressureFactors mediating the pressor response to isometric muscle contraction: An experimental study in healthy volunteers during lower body negative pressure. PLOS ONE. 15:e0243627(12), p. 1–15. doi: 10.1371/journal.pone.0243627. Full text in Research Archive Show summary

  Whilst both cardiac output (CO) and total peripheral resistance (TPR) determine mean arterial blood pressure (MAP), their relative importance in the pressor response to isometric exercise remains unclear. This study aimed to elucidate the relative importance of these two different factors by examining pressor responses during cardiopulmonary unloading leading to step-wise reductions in CO. Hemodynamics were investigated in 11 healthy individuals before, during and after two-minute isometric exercise during lower body negative pressure (LBNP; -20mmHg and -40mmHg). The blood pressure response to isometric exercise was similar during normal and reduced preload, despite a step-wise reduction in CO during LBNP (-20mmHg and -40mmHg). During -20mmHg LBNP, the decreased stroke volume, and consequently CO, was counteracted by an increased TPR, while heart rate (HR) was unaffected. HR was increased during -40 mmHg LBNP, although insufficient to maintain CO; the drop in CO was perfectly compensated by an increased TPR to maintain MAP. Likewise, transient application of LBNP (-20mmHg and -40mmHg) resulted in a short transient drop in MAP, caused by a decrease in CO, which was compensated by an increase in TPR. This study suggests that, in case of reductions of CO, changes in TPR are primarily responsible for maintaining the pressor response during isometric exercise. This highlights the relative importance of TPR compared to CO in mediating the pressor response during isometric exercise.

• Storsve, Andreas B.; Johnsen, Line; Nyborg, Christoffer; Melau, Jørgen; Hisdal, Jonny & Burri, Lena (2020). Effects of Krill Oil and Race Distance on Serum Choline and Choline Metabolites in Triathletes: A Field Study. Frontiers in Nutrition. 7. doi: 10.3389/fnut.2020.00133. Full text in Research Archive Show summary

  Choline is an essential nutrient that has been implicated in athletic performance due to its role in maintaining normal muscle function. The concentration of free choline in serum may decrease during long-distance high-intensity exercise, yet few nutritional strategies to counteract this potentially performance-depleting loss in choline have been investigated outside the laboratory. This exploratory field study was performed to investigate if pre-race supplementation with phosphatidylcholine from krill oil can counteract the expected drop in choline and some of its metabolites during triathlon competitions. Forty-seven triathletes, 12 females and 35 males ranging in age from 25 to 61 years, were recruited from participants in the Ironman-distance Norseman Xtreme triathlon and the Sprint/Olympic-distance Oslo Triathlon. Twenty-four athletes were randomly allocated to the krill oil group, receiving 4 g of SuperbaBoost™ krill oil daily for 5 weeks prior to the race, and 23 athletes were randomly allocated to the placebo group, receiving 4 g of mixed vegetable oil daily. Blood samples were obtained before the race, immediately after completion of the race, and the day after the race for analysis of choline and its metabolites. The results showed that serum choline concentrations significantly decreased from pre-race to race finish in all races, with a more pronounced decrease observed in the Ironman-distance Norseman Xtreme triathlon (34% decrease) relative to the Sprint/Olympic-distance Oslo Triathlon (15% decrease). A reduction in betaine was also observed, while dimethylglycine (DMG) concentrations remained stable across all time points. Significantly higher concentrations of choline (9.4% on average) and DMG (21.4% on average) were observed in the krill oil compared to the placebo group, and the krill oil group showed a significantly greater increase in serum choline following race completion. In conclusion, krill oil may help to prevent that circulating choline concentrations become limiting during endurance competitions.

• Stensrud, Trine; Rossvoll, Øyvind; Mathiassen, Maria; Melau, Jørgen; Illidi, Camilla Rønn & Østgaard, Hege Nymo [Show all 8 contributors for this article] (2020). Lung function and oxygen saturation after participation in Norseman Xtreme Triathlon. Scandinavian Journal of Medicine & Science in Sports. ISSN 0905-7188. 30(6), p. 1008–1016. doi: 10.1111/sms.13651. Full text in Research Archive Show summary

  Objectives: To examine evidence of exercise-induced bronchoconstriction (EIB) defined as ≥10% reduction in forced expiratory volume in one second (FEV1 ) and exercise-induced arterial hypoxemia (EIAH) defined as ≥4% reduction in oxygen saturation (SpO2 ) from before to after participation in the Norseman Xtreme Triathlon. Secondarily, to assess whether changes in FEV1 and SpO2 are related to respiratory symptoms, training volume, and race time. Methods: In this quasi-experimental non-controlled study, we included 63 triathletes (50♂/13♀) aged 40.3 (±9.0) years (mean ± SD). Fifty-seven (46♂/11♀) measured lung function and 54 (44♂/10♀) measured SpO2 before the race, 8-10 minutes after the race (post-test 1) and the day after the race (post-test 2). Respiratory symptoms and training volume were recorded with modified AQUA questionnaire. ANOVA for repeated measures was used to detect differences in lung function and SpO2 . Statistical significance was accepted at 0.05 level. Results: Twenty-six participants (46%) presented with EIB at post-test 1 and 16 (28%) at post-test 2. Lung function variables were significantly reduced from baseline to post-test 1 and 2. Thirty-five participants (65%) showed evidence of mild to moderate EIAH. No significant correlations were observed except a weak correlation between maximal reduction in FEV1 and respiratory symptoms (r = 0.35, P = .016). Conclusion: Our results demonstrated that 46% of the participants presented with EIB and 65% showed evidence of EIAH after the Norseman Xtreme Triathlon. Changes in FEV1 and SpO2 were not correlated to weekly training hours or race time. We observed a weak correlation between maximal reduction in FEV1 and respiratory symptoms.

• Elstad, Tiril; Ulleberg, Pål; Klonteig, Sandra; Hisdal, Jonny; Dyrdal, Gunvor Marie & Bjørndal, Arild (2020). The effects of yoga on student mental health: a randomised controlled trial. Health Psychology and Behavioral Medicine. 8(1), p. 573–586. doi: 10.1080/21642850.2020.1843466. Full text in Research Archive Show summary

  Background Universities around the world are facing an epidemic of mental distress among their students. The problem is truly a public health issue, affecting many and with serious consequences. The global burden of disease-agenda calls for effective interventions with lasting effects that have the potential to improve the mental health of young adults. In this study we aimed to determine whether yoga, a popular and widely available mind-body practice, can improve student mental health. Methods We performed a randomised controlled trial with 202 healthy university students in the Oslo area. The participants were assigned to a yoga group or waitlist control group in a 1:1 ratio by a simple online randomisation program. The intervention group was offered 24 yoga sessions over 12 weeks. Measurements were taken at week 0 (baseline), week 12 (post-intervention), and week 24 (follow-up). The primary outcome was psychological distress assessed by the HSCL-25 questionnaire. Analysis was performed based on the intention to treat-principle. Results Between 24 January 2017, and 27 August 2017, we randomly assigned 202 students to a yoga intervention group (n = 100), or waitlist control group (n = 102). Compared with the control group, the yoga participants demonstrated a significant reduction in distress symptoms both at post-intervention (adjusted difference in the mean change −0.15, 95% CI −0.26 to −0.03, p = 0.0110) and follow-up (adjusted difference in the mean change −0.18, 95% CI −0.29 to −0.06, p = 0.0025). Sleep quality also improved at post-intervention and follow-up. No adverse events were reported. Conclusions Our findings suggest that yoga has a moderately large and lasting effect, at least for some months, reducing symptoms of distress and improving sleep quality among students. Further research should seek ways to enhance the effect, assess an even longer follow-up period, include active control groups, and consider performing similar studies in other cultural settings.

• Amini, Maryam; Niemi, Essi Maria; Hisdal, Jonny; Kalvøy, Håvard; Tronstad, Christian & Scholz, Hanne [Show all 8 contributors for this article] (2020). Monitoring the quality of frozen-thawed venous segments using bioimpedance spectroscopy. Physiological Measurement. ISSN 0967-3334. 41(4). doi: 10.1088/1361-6579/ab85b7. Full text in Research Archive Show summary

  Objective: Storage at temperatures as low as −80 °C and below (cryopreservation) is considered a method for long-term preservation of cells and tissues, and especially blood vessel segments, which are to be used for clinical operations such as transplantation. However, the freezing and thawing processes themselves can induce injuries to the cells and tissue by damaging the structure and consequently functionality of the cryopreserved tissue. In addition, the level of damage is dependent on the rate of cooling and warming used during the freezing-thawing process. Current methods for monitoring the viability and integrity of cells and tissues after going through the freezing-thawing cycle are usually invasive and destructive to the cells and tissues. Therefore, employing monitoring methods which are not destructive to the cryopreserved tissues, such as bioimpedance measurement techniques, is necessary. In this study we aimed to design a bioimpedance measurement setup to detect changes in venous segments after freezing-thawing cycles in a noninvasive manner. Approach: A bioimpedance spectroscopy measurement technique with a two-electrode setup was employed to monitor ovine jugular vein segments after each cycle during a process of seven freezing-thawing cycles. Main results: The results demonstrated changes in the impedance spectra of the measured venous segments after each freezing-thawing cycle. Significance: This indicates that bioimpedance spectroscopy has the potential to be developed into a novel method for non-invasive and non-destructive monitoring of the viability of complex tissue after cryopreservation.

• Berge, Simen Tveten; Safi, Nathkai; Medhus, Asle Wilhelm; Sundhagen, Jon Otto; Hisdal, Jonny & Kazmi, Syed Sajid Hussain (2020). Perioperative microcirculatory changes detected with gastroscopy assisted laser doppler flowmetry and visible light spectroscopy in patients with median arcuate ligament syndrome. Vascular Health and Risk Management. ISSN 1176-6344. 16, p. 331–341. doi: 10.2147/VHRM.S252192. Full text in Research Archive Show summary

  Purpose: Physiological tests may aid in diagnosing median arcuate ligament syndrome (MALS). MALS is a symptomatic compression of the celiac artery causing symptoms similar to chronic mesenteric ischemia (CMI) of atherosclerotic etiology. Simultaneous use of visible light spectroscopy (VLS) and laser doppler flowmetry (LDF) during upper endoscopy may detect microcirculatory changes in these patients. Patients and Methods: In a single-center, prospective comparative cohort, 25 patients were evaluated for MALS. Patients with a consensus diagnosis of MALS (n=15) underwent a gastroscopy assisted, transmucosal microcirculatory assessment with LDF and VLS. Results were compared to individuals with normal intestinal circulation (n=38) evaluated with duplex ultrasonography, and to patients with chronic mesenteric ischemia (n=32). Treatment response was evaluated clinically at 1, 3, 6, and 12 months, and with ultrasound, VLS and LDF at three months. Health-related quality of life (QoL) was assessed with Euroqol (EQ-5D-5L), preoperatively, and 12 months postoperatively. Results: Preoperative mean transmucosal oxygen saturation was significantly lower in patients with MALS (SO2 76± 6), as compared to healthy individuals (SO2 81± 4), p=0.02. An overall significant improvement in SO2 after surgical decompression of the celiac artery was found (SO2 81± 3.7, p=0.05). Eleven (92%) patients with clinical improvement after laparoscopic decompression had a definitive diagnosis of MALS. Median follow-up was 18 months (4– 24 months). Four of the five dimensions investigated with EQ-5D-5L improved. Conclusion: VLS detected a significantly lower baseline transmucosal SO2 in patients with MALS as compared to control subjects with normal intestinal circulation. An improvement in SO2 after laparoscopic decompression was found, supporting a possible ischemic etiology in our patient population.

• Lund, Tormod; Svindland, Aud; Bay, Dag; Sundhagen, Jon Otto; Hisdal, Jonny & Flørnes, Tor Leif (2020). Histological Analysis of a Long Term Patent Subintimal Canal in theSuperficial Femoral Artery. EJVES Short Reports. 50, p. 19–23. doi: 10.1016/j.ejvsvf.2020.12.023. Full text in Research Archive Show summary

  The subintimal canal was created in the medial layer of the vessel wall. Early and late stage atherosclerosis is observed throughout the subintimal canal. Neo-cellularisation of single layer luminal cells is apparent in the subintimal canal. The findings underscore the need for surveillance of subintimal canals.

• Tønnessen, Espen; Hisdal, Jonny & Rønnestad, Bent (2020). Influence of interval training frequency on time-trial performance in elite endurance athletes. International Journal of Environmental Research and Public Health (IJERPH). ISSN 1661-7827. 17(9). doi: 10.3390/ijerph17093190. Full text in Research Archive
• Johnsen, Lydia; Hisdal, Jonny; Jonung, Torbjörn; Braaten, Audun Ole & Pedersen, Gustav (2020). Contrast-enhanced ultrasound detects type II endoleaks during follow-up for endovascular aneurysm repair. Journal of Vascular Surgery. ISSN 0741-5214. 72(6), p. 1952–1959. doi: 10.1016/j.jvs.2020.02.020. Full text in Research Archive
• Amini, Maryam; Hisdal, Jonny; Rosales, Antonio; Kalvøy, Håvard & Martinsen, Ørjan Grøttem (2020). Evaluating the Effects of Cold Storage on Vascular Grafts Using Bioimpedance Measurement Techniques. International Federation for Medical and Biological Engineering Proceedings. ISSN 1680-0737. p. 127–132. doi: 10.1007/978-981-13-3498-6_19. Full text in Research Archive
• Nyborg, Christoffer; Melau, Jørgen; Bonnevie-Svendsen, Martin; Mathiassen, Maria; Melsom, Helene Støle & Storsve, Andreas Berg [Show all 7 contributors for this article] (2020). Biochemical markers after the Norseman Extreme Triathlon. PLOS ONE. 15:e0239158(9), p. 1–15. doi: 10.1371/journal.pone.0239158. Full text in Research Archive Show summary

  Prolonged exercise is known to cause changes in common biomarkers. Occasionally, competition athletes need medical assistance and hospitalisation during prolonged exercise events. To aid clinicians treating patients and medical teams in such events we have studied common biomarkers after at The Norseman Xtreme Triathlon (Norseman), an Ironman distance triathlon with an accumulated climb of 5200 m, and an Olympic triathlon for comparison. Blood samples were collected before, immediately after, and the day following the Norseman Xtreme Triatlon (n = 98) and Oslo Olympic Triathlon (n = 15). Increased levels of clinical significance were seen at the finish line of the Norseman in white blood cells count (WBC) (14.2 [13.5-14.9] 109/L, p

• Hilde, Janne Mykland; Hisdal, Jonny; Skjørten, Ingunn; Hansteen, Viggo; Melsom, Morten Nissen & Grøtta, Ole Jørgen [Show all 11 contributors for this article] (2020). Left ventricular dysfunction in COPD without pulmonary hypertension. PLOS ONE. 15(7), p. 1–15. doi: 10.1371/journal.pone.0235075. Full text in Research Archive Show summary

  Objectives: We aimed to assess prevalence of left ventricular (LV) systolic and diastolic function in stable cohort of COPD patients, where LV disease had been thoroughly excluded in advance. Methods: 100 COPD outpatients in GOLD II-IV and 34 controls were included. Patients were divided by invasive mean pulmonary artery pressure (mPAP) in COPD-PH (≥25 mmHg) and COPD-non-PH (<25 mmHg), which was subdivided in mPAP ≤20 mmHg and 21–24 mmHg. LV myocardial performance index (LV MPI) and strain by tissue Doppler imaging (TDI) were used for evaluation of LV global and systolic function, respectively. LV MPI ≥0.51 and strain ≤-15.8% were considered abnormal. LV diastolic function was assessed by the ratio between peak early (E) and late (A) velocity, early TDI E´, E/E´, isovolumic relaxation time, and left atrium volume. Results: LV MPI ≥0.51 was found in 64.9% and 88.5% and LV strain ≤-15.8% in 62.2.% and 76.9% in the COPD-non-PH and COPD-PH patients, respectively. Similarly, LV MPI and LV strain were impaired even in patients with mPAP <20 mmHg. In multiple regression analyses, residual volume and stroke volume were best associated to LV MPI and LV strain, respectively. Except for isovolumic relaxation time, standard diastolic echo indices as E/A, E´, E/E´ and left atrium volume did not change from normal individuals to COPD-non-PH. Conclusions: Subclinical LV systolic dysfunction was a frequent finding in this cohort of COPD patients, even in those with normal pulmonary artery pressure. Evidence of LV diastolic dysfunction was hardly present as measured by conventional echo indices.

• Berge, Simen Tveten; Safi, Nathkai; Medhus, Asle Wilhelm; Ånonsen, Kim Vidar; Sundhagen, Jon Otto & Hisdal, Jonny [Show all 7 contributors for this article] (2019). Gastroscopy assisted laser Doppler flowmetry and visible light spectroscopy in patients with chronic mesenteric ischemia. Scandinavian Journal of Clinical and Laboratory Investigation. ISSN 0036-5513. 79(7), p. 541–549. doi: 10.1080/00365513.2019.1672084. Full text in Research Archive Show summary

  Mucosal pathology due to chronic mesenteric ischemia (CMI) is rarely seen during upper endoscopy. Combining Laser Doppler Flowmetry (LDF) and Visible Light Spectroscopy (VLS) may aid in detection of CMI at an early stage. We aimed to investigate the utility of LDF and VLS in detecting microcirculatory changes in patients with CMI during upper endoscopy. In a single center, prospective study, 104 patients were evaluated for mesenteric ischemia during a 24 months period. Patients with a consensus diagnosis of CMI (n = 40) were examined with LDF and VLS. Thirty-two were successfully treated and had a definitive diagnosis of CMI. Results were compared with controls (n = 38) with normal intestinal circulation evaluated with duplex ultrasonography (DUS). Treatment response was evaluated clinically and with DUS at 1 month and with VLS and LDF at 3 months. A significant reduction in mucosal capillary hemoglobin oxygen saturation (SO2) was found in CMI patients compared to controls before treatment: mean ± SD: 67 ± 9%, 81 ± 4%, respectively (p < .001). A significant reduction was also seen for the relative hemoglobin (rHb) amount, flow and velocity (p < .001). The sensitivity of SO2 measured by VLS for diagnosing CMI was 94% and the specificity 72% (cut-off 78%), calculated with ROC curve analysis. A combination of SO2 and rHb increased the test sensitivity and specificity to 97% and 79%, respectively. Conclusion: CMI patients have significantly reduced microcirculation in the stomach and duodenum compared to controls. The results suggest that VLS should be included when performing an upper endoscopy in patients with suspected CMI.

• Gundersen, Kristian Magnus; Nyborg, Christoffer; Sundby, Øivind Heiberg & Hisdal, Jonny (2019). The effects of sympathetic activity induced by ice water on blood flow and brachial artery flow-mediated dilatation response in healthy volunteers. PLOS ONE. 14(9). doi: 10.1371/journal.pone.0219814. Full text in Research Archive Show summary

  Objective To investigate the association between sympathetic activity, reactive hyperemia and brachial artery flow-mediated dilation (FMD). Background It is claimed that major surgery has an impact on endothelial function, as observed by post-operative reduced brachial artery FMD response. However, another explanation for the observed reduced FMD response post-operatively may be sympathetic stress-induced reduction in blood flow. Methods Seventeen healthy volunteers with a median age (25th-75th percentiles) of 23.5 (23–24.8) years were recruited. Participants’ brachial blood flow and FMD response were measured (i) during normal non-stress conditions (Normal1); (ii) during exposure to ice water; and (iii) afterwards, under normal non-stress conditions (Normal2). We continuously measured arterial blood pressure (Finometer), heart rate (ECG), skin blood flow of the index finger (laser Doppler), and brachial artery blood flow and diameter (Ultrasound Doppler). Measurements were taken at baseline; before a 5-min suprasystolic forearm occlusion; and following a 3-min post-occlusion, to measure reactive hyperemia and FMD. Results Median (25th-75th percentiles) FMD response after exposure to ice water was reduced compared to non-stress conditions [4.9 (2.9–8.4) % during ice water vs. 9.7 (7.6–12.2) % Normal1 and 9.7 (6.4–10.3) % Normal2, P < 0.001]. Blood flow 60 s after cuff-deflation during ice water exposure was significantly reduced to 328 (289–421) mL compared to non-stress conditions (both P < 0.05). No differences were observed between Normal1 [446 (359–506) mL] and Normal2 [455 (365–515) mL] (both P > 0.05). Heart rate significantly increased during ice water exposure [67 (59–69) beats/min)] compared to 55 (49–60) beats/min during Normal1 and 54 (47–60) beats/min during Normal2 (both P < 0.05). MAP did not change during Normal1 [72 (64–84)] or during Normal2 [71 (65–81) mm Hg] (both P > 0.05), but increased to 86 (75–98) mm Hg during ice water exposure (P < 0.05). Conclusions Increased sympathetic activity resulted in decreased blood flow and brachial artery FMD response in healthy volunteers, independent of endothelial dysfunction. Future studies should adjust for blood flow when interpreting the FMD response.

• Pettersen, Erik Mulder; Avdal, Jørgen; Hisdal, Jonny; Torp, Hans & Seternes, Arne (2019). Validation of a novel ultrasound Doppler monitoring device (earlybird) for detection of microvascular circulatory changes. Clinical Hemorheology and Microcirculation. ISSN 1386-0291. doi: 10.3233/CH-190707. Full text in Research Archive
• Melau, Jørgen; Mathiassen, Maria; Stensrud, Trine; Tipton, Mike & Hisdal, Jonny (2019). Core temperature in triathletes during swimming with wetsuit in 10^◦c cold water. Sports. 7(6). doi: 10.3390/sports7060130. Full text in Research Archive Show summary

  Low water temperature (<15 °C) has been faced by many organizers of triathlons and swim-runs in the northern part of Europe during recent years. More knowledge about how cold water affects athletes swimming in wetsuits in cold water is warranted. The aim of the present study was therefore to investigate the physiological response when swimming a full Ironman distance (3800 m) in a wetsuit in 10 °C water. Twenty triathletes, 37.6 ± 9 years (12 males and 8 females) were recruited to perform open water swimming in 10 °C seawater; while rectal temperature (Tre) and skin temperature (Tskin) were recorded. The results showed that for all participants, Tre was maintained for the first 10–15 min of the swim; and no participants dropped more than 2 °C in Tre during the first 30 min of swimming in 10 °C water. However; according to extrapolations of the results, during a swim time above 135 min; 47% (8/17) of the participants in the present study would fall more than 2 °C in Tre during the swim. The results show that the temperature response to swimming in a wetsuit in 10 °C water is highly individual. However, no participant in the present study dropped more than 2 °C in Tre during the first 30 min of the swim in 10 °C water.

• Hisdal, Jonny; Landsverk, Svein A.; Hoff, Ingrid Elise Taraldsrud; Hagen, Ove Andreas; Kirkebøen, Knut Arvid & Høiseth, Lars Øivind (2019). Associations between changes in precerebral blood flow and cerebral oximetry in the lower body negative pressure model of hypovolemia in healthy volunteers. PLOS ONE. 14(6), p. 1–14. doi: 10.1371/journal.pone.0219154. Full text in Research Archive Show summary

  Reductions in cerebral oxygen saturation (ScO2) measured by near infra-red spectroscopy have been found during compensated hypovolemia in the lower body negative pressure (LBNP)-model, which may reflect reduced cerebral blood flow. However, ScO2 may also be contaminated from extracranial (scalp) tissues, mainly supplied by the external carotid artery (ECA), and it is possible that a ScO2 reduction during hypovolemia is caused by reduced scalp, and not cerebral, blood flow. The aim of the present study was to explore the associations between blood flow in precerebral arteries and ScO2 during LBNP-induced hypovolemia. Twenty healthy volunteers were exposed to LBNP 20, 40, 60 and 80 mmHg. Blood flow in the internal carotid artery (ICA), ECA and vertebral artery (VA) was measured by Doppler ultrasound. Stroke volume for calculating cardiac output was measured by suprasternal Doppler. Associations of changes within subjects were examined using linear mixed-effects regression models. LBNP reduced cardiac output, ScO2 and ICA and ECA blood flow. Changes in flow in both ICA and ECA were associated with changes in ScO2 and cardiac output. Flow in the VA did not change during LBNP and changes in VA flow were not associated with changes in ScO2 or cardiac output. During experimental compensated hypovolemia in healthy, conscious subjects, a reduced ScO2 may thus reflect a reduction in both cerebral and extracranial blood flow.

• Valsdottir, Thorhildur; Henriksen, Christine; Odden, Nancy; Nellemann, Birgitte; Jeppesen, Per B & Hisdal, Jonny [Show all 8 contributors for this article] (2019). Effect of a Low-Carbohydrate High-Fat Diet and a Single Bout of Exercise on Glucose Tolerance, Lipid Profile and Endothelial Function in Normal Weight Young Healthy Females. Frontiers in Physiology. 10, p. 1–15. doi: 10.3389/fphys.2019.01499. Full text in Research Archive Show summary

  Low-carbohydrate-high-fat (LCHF) diets are efficient for weight loss, and are also used by healthy people to maintain bodyweight. The main aim of this study was to investigate the effect of 3-week energy-balanced LCHF-diet, with >75 percentage energy (E%) from fat, on glucose tolerance and lipid profile in normal weight, young, healthy women. The second aim of the study was to investigate if a bout of exercise would prevent any negative effect of LCHF-diet on glucose tolerance. Seventeen females participated, age 23.5 ± 0.5 years; body mass index 21.0 ± 0.4 kg/m2, with a mean dietary intake of 78 ± 1 E% fat, 19 ± 1 E% protein and 3 ± 0 E% carbohydrates. Measurements were performed at baseline and post-intervention. Fasting glucose decreased from 4.7 ± 0.1 to 4.4 mmol/L (p < 0.001) during the dietary intervention whereas fasting insulin was unaffected. Glucose area under the curve (AUC) and insulin AUC did not change during an OGTT after the intervention. Before the intervention, a bout of aerobic exercise reduced fasting glucose (4.4 ± 0.1 mmol/L, p < 0.001) and glucose AUC (739 ± 41 to 661 ± 25, p = 0.008) during OGTT the following morning. After the intervention, exercise did not reduce fasting glucose the following morning, and glucose AUC during an OGTT increased compared to the day before (789 ± 43 to 889 ± 40 mmol/L∙120min–1, p = 0.001). AUC for insulin was unaffected. The dietary intervention increased total cholesterol (p < 0.001), low-density lipoprotein (p ≤ 0.001), high-density lipoprotein (p = 0.011), triglycerides (p = 0.035), and free fatty acids (p = 0.021). In conclusion, 3-week LCHF-diet reduced fasting glucose, while glucose tolerance was unaffected. A bout of exercise post-intervention did not decrease AUC glucose as it did at baseline. Total cholesterol increased, mainly due to increments in low-density lipoprotein. LCHF-diets should be further evaluated and carefully considered for healthy individuals.

• Svanteson, Mona; Rollefstad, Silvia Christin Hellerud; Kløw, Nils-Einar; Hisdal, Jonny; Ikdahl, Eirik & Sexton, Joseph [Show all 8 contributors for this article] (2019). Effects of long-term statin-treatment on coronary atherosclerosis in patients with inflammatory joint diseases. PLOS ONE. 14(12), p. 1–15. doi: 10.1371/journal.pone.0226479. Full text in Research Archive Show summary

  Background The effect of statins over time on coronary atherosclerosis in patients with inflammatory joint diseases (IJD) is unknown. Our aim was to evaluate the change in coronary plaque morphology and volume in long-term statin-treated patients with IJD. Methods Sixty-eight patients with IJD and carotid artery plaque(s) underwent coronary computed tomography angiography before and after a mean of 4.7 (range 4.0–6.0) years of statin treatment. The treatment target for low density lipoprotein cholesterol (LDL-c) was ≤1.8 mmol/L. Changes in plaque volume (calcified, mixed/soft and total) and coronary artery calcification (CAC) from baseline to follow-up were assessed using the 17-segment American Heart Association-model. Results Median (IQR) increase in CAC after statin treatment was 38 (5–236) Agatston units (p<0.001). Calcified and total plaque volume increased with 5.6 (0.0–49.1) and 2.9 (0.0–23.5) mm3, respectively (p<0.001 for both). The median (IQR) change in soft/mixed plaque volume was -10 (-7.1–0.0), p = <0.001. Patients who had obtained the LDL-c treatment target at follow-up, experienced reduced progression of both CAC and total plaque volume compared to patients with LDL-c >1.8mmol/L (21 [2–143] vs. 69 [16–423], p = 0.006 and 0.65 [-1.0–13.9] vs. 13.0 [0.0–60.8] mm3, p = 0.019, respectively). Conclusions A progression of total atherosclerotic plaque volume in statin-treated patients with IJD was observed. However, soft/mixed plaque volume was reduced, suggesting an alteration in plaque composition. Patients with recommended LDL-c levels at follow-up had reduced atherosclerotic progression compared to patients with LDL-c levels above the treatment target, suggesting a beneficial effect of treatment to guideline-recommended lipid targets in IJD patients.

• Holder, Sophie M; Dawson, Ellen A; Brislane, Aine; Hisdal, Jonny; Green, Daniel J. & Thijssen, Dick HJ (2019). Fluctuation in shear rate, with unaltered mean shear rate, improves brachial artery flow-mediated dilation in healthy, young men. Journal of applied physiology. ISSN 8750-7587. 126(6), p. 1687–1693. doi: 10.1152/japplphysiol.00009.2019. Full text in Research Archive
• Hoff, Ingrid Elise Taraldsrud; Hisdal, Jonny; Landsverk, Svein A.; Røislien, Jo; Kirkebøen, Knut Arvid & Høiseth, Lars Øivind (2019). Respiratory variations in pulse pressure and photoplethysmographic waveform amplitude during positive expiratory pressure and continuous positive airway pressure in a model of progressive hypovolemia. PLOS ONE. 14:e0223071(9), p. 1–15. doi: 10.1371/journal.pone.0223071. Full text in Research Archive Show summary

  Purpose Respiratory variations in pulse pressure (dPP) and photoplethysmographic waveform amplitude (dPOP) are used for evaluation of volume status in mechanically ventilated patients. Amplification of intrathoracic pressure changes may enable their use also during spontaneous breathing. We investigated the association between the degree of hypovolemia and dPP and dPOP at different levels of two commonly applied clinical interventions; positive expiratory pressure (PEP) and continuous positive airway pressure (CPAP). Methods 20 healthy volunteers were exposed to progressive hypovolemia by lower body negative pressure (LBNP). PEP of 0 (baseline), 5 and 10 cmH2O was applied by an expiratory resistor and CPAP of 0 (baseline), 5 and 10 cmH2O by a facemask. dPP was obtained non-invasively with the volume clamp method and dPOP from a pulse oximeter. Central venous pressure was measured in 10 subjects. Associations between changes were examined using linear mixed-effects regression models. Results dPP increased with progressive LBNP at all levels of PEP and CPAP. The LBNP-induced increase in dPP was amplified by PEP 10 cmH20. dPOP increased with progressive LBNP during PEP 5 and PEP 10, and during all levels of CPAP. There was no additional effect of the level of PEP or CPAP on dPOP. Progressive hypovolemia and increasing levels of PEP were reflected by increasing respiratory variations in CVP. Conclusion dPP and dPOP reflected progressive hypovolemia in spontaneously breathing healthy volunteers during PEP and CPAP. An increase in PEP from baseline to 10 cmH2O augmented the increase in dPP, but not in dPOP.

• Hoel, Henrik; Høiseth, Lars Øivind; Sandbæk, Gunnar; Sundhagen, Jon Otto; Mathiesen, Iacob & Hisdal, Jonny (2019). The acute effects of different levels of intermittent negative pressure on peripheral circulation in patients with peripheral artery disease. Physiological Reports. 7:e14241(20), p. 1–8. doi: 10.14814/phy2.14241. Full text in Research Archive Show summary

  Intermittent negative pressure (INP) applied to the lower leg induces acute increase in arterial and skin blood flow. The aim of this study was to identify the optimal level of INP to increase blood flow in patients with lower extremity peripheral artery disease (PAD). We investigated the acute effects of different levels of INP in 16 subjects (7 women and 9 men, mean (SD) age 71(8) years) diagnosed with PAD. During application of INP in a pressure chamber sealed below the knee, arterial blood flow was continuously recorded in the dorsalis pedis artery or tibialis posterior artery (ultrasound Doppler), and skin blood flow was continuously recorded at the pulp of the first toe (laser Doppler). Different pressure levels (0, −10, −20, −40, and −60 mmHg) were tested in randomized order. Maximal arterial blood flow relative to baseline (median [25th, 75th percentiles]) was: 0 mmHg; 1.08 (1.02, 1.13), −10 mmHg; 1.11 (1.07, 1.17), −20 mmHg; 1.18 (1.11, 1.32), −40 mmHg; 1.39 (1.27, 1.91) and −60 mmHg; 1.48 (1.37, 1.78). Maximal laser Doppler flux (LDF) relative to baseline was: 0 mmHg; 1.06 (1.02, 1.12), −10 mmHg; 1.08 (1.05, 1.16) −20 mmHg; 1.12 (1.06, 1.27), −40 mmHg; 1.24 (1.14, 1.50) and −60 mmHg; 1.35 (1.10, 1.70). There were significantly higher maximal arterial blood flow and maximal LDF at −40 mmHg compared with −10 mmHg (P = 0.001 and P = 0.025, respectively). There were no significant differences in maximal arterial blood flow and maximal LDF between 0 and −10 mmHg (both P = 1.0), or between −40 and −60 mmHg (both P = 1.0). INP of −40 mmHg was the lowest negative pressure level that increased blood flow.

• Skjørten, Ingunn; Hilde, Janne Mykland; Melsom, Morten Nissen; Hisdal, Jonny; Hansteen, Viggo & Steine, Kjetil [Show all 7 contributors for this article] (2018). Exercise capacity in COPD patients with exercise-induced pulmonary hypertension. The International Journal of Chronic Obstructive Pulmonary Disease. ISSN 1176-9106. 13, p. 3599–3610. doi: 10.2147/COPD.S161175. Full text in Research Archive Show summary

  Background: Pulmonary hypertension (PH) in patients with COPD is associated with reduced exercise capacity. A subgroup of COPD patients has normal mean pulmonary artery pressure (mPAP) at rest, but develops high mPAP relative to cardiac output (CO) during exercise, a condition we refer to as exercise-induced pulmonary hypertension (EIPH). We hypothesized that COPD patients with EIPH could be identified by cardiopulmonary exercise test (CPET) and that these patients have lower exercise capacity and more abnormal CPET parameters compared to COPD patients with normal hemodynamic exercise response. Methods: Ninety-three stable outpatients with COPD underwent right heart catheterization with the measurement of mPAP, CO, and capillary wedge pressure at rest and during supine exercise. Resting mPAP <25 mmHg with ΔmPAP/ΔCO slope above or below 3 mmHg/L/min were defined as COPD-EIPH and COPD-normal, respectively. Pulmonary function tests and CPET with arterial blood gases were performed. Linear mixed models were fitted to estimate differences between the groups with adjustment for gender, age, and airflow obstruction. Results: EIPH was observed in 45% of the study population. Maximal workload was lower in COPD-EIPH compared to COPD-normal, whereas other CPET measurements at peak exercise in % predicted values were similar between the two groups. After adjustment for gender, age, and airflow obstruction, patients with COPD-EIPH showed significantly greater increase in oxygen uptake, ventilation, respiratory frequency, heart rate, and lactate with increasing work load, as well as more reduction in pH compared to those with normal hemodynamic responses. Conclusion: COPD-EIPH could not be discriminated from COPD-normal by CPET. However, COPD-EIPH experienced a higher cost of exercise in terms of higher oxygen uptake, ventilation, respiratory frequency, heart rate, and lactate for a given increase in workload compared to COPD-normal.

• Amini, Maryam; Hisdal, Jonny & Kalvøy, Håvard (2018). Applications of bioimpedance measurement techniques in tissue engineering. Journal of Electrical Bioimpedance. 9(1), p. 142–158. doi: 10.2478/joeb-2018-0019. Full text in Research Archive Show summary

  Rapid development in the field of tissue engineering necessitates implementation of monitoring methods for evaluation of the viability and characteristics of the cell cultures in a real-time, non-invasive and non-destructive manner. Current monitoring techniques are mainly histological and require labeling and involve destructive tests to characterize cell cultures. Bioimpedance measurement technique which benefits from measurement of electrical properties of the biological tissues, offers a non-invasive, label-free and real-time solution for monitoring tissue engineered constructs. This review outlines the fundamentals of bioimpedance, as well as electrical properties of the biological tissues, different types of cell culture constructs and possible electrode configuration set ups for performing bioimpedance measurements on these cell cultures. In addition, various bioimpedance measurement techniques and their applications in the field of tissue engineering are discussed.

• Aalen, John; Storsten, Petter; Remme, Espen W.; Sirnes, Per A.; Gjesdal, Ola & Larsen, Camilla Kjellstad [Show all 11 contributors for this article] (2018). Afterload hypersensitivity in patients with left bundle branch block. JACC Cardiovascular Imaging. ISSN 1936-878X. p. 1–11. doi: 10.1016/j.jcmg.2017.11.025. Full text in Research Archive
• Bjørnsen, Thomas; Wernbom, Mathias; Løvstad, Amund T.; Paulsen, Gøran; D'Souza, Randall F & Cameron-Smith, David [Show all 10 contributors for this article] (2018). Delayed myonuclear addition, myofiber hypertrophyand increases in strength with frequent low-load blood flow restricted training to volitional failure. Journal of applied physiology. ISSN 8750-7587. doi: 10.1152/japplphysiol.00397.2018. Full text in Research Archive Show summary

  PURPOSE: To investigate muscle hypertrophy, strength, myonuclear and satellite cell (SC) responses to high-frequency blood flow restricted resistance exercise (BFRRE). METHODS: Thirteen individuals (24±2 years [mean ± SD], 9 males) completed two 5-day-blocks of 7 BFRRE sessions, separated by a 10-day rest period. Four sets of unilateral knee extensions to voluntary failure at 20% of 1RM were conducted with partial blood flow restriction (90-100 mmHg). Muscle samples obtained before-, during, 3- and 10 days after training were analyzed for muscle fiber area (MFA), myonuclei, SC, and mRNA and miRNA expression. Muscle size was measured by ultrasonography and magnetic resonance imaging, and strength with 1RM knee-extension. RESULTS: With the first block of BFRRE, SC number increased in both fiber types (70-80%, p<0.05), while type I and II MFA decreased by 6±7% and 15±11% (p<0.05), respectively. With the second block of training, muscle size increased by 6-8%, while the number of SC (type I: 80±63%, type II 147±95%), myonuclei (type I: 30±24%, type II: 31±28%) and MFA (type I: 19±19%, type II: 11±19%) peaked 10 days after the second block of BFRRE, whereas strength peaked after 20 days of detraining (6±6%, p<0.05). Pax7- and p21 mRNA expression were elevated during the intervention, while myostatin, IGF1R, MyoD, myogenin, cyclinD1 and -D2 mRNA did not change until 3-10 days post intervention. CONCLUSION: High frequency low-load BFRRE induced robust increases in SC, myonuclei and muscle size, but modest strength gains. Intriguingly, the responses were delayed and peaked 10-20 days after the training intervention, indicating overreaching.

• Rambøl, Mia Marie-Elisabeth; Hisdal, Jonny; Sundhagen, Jon Otto; Brinchmann, Jan E. & Rosales, Antonio (2018). Recellularization of decellularized venous grafts using peripheral blood: a critical evaluation. EBioMedicine. 32, p. 215–222. doi: 10.1016/j.ebiom.2018.05.012. Full text in Research Archive Show summary

  Vascular disease is a major cause of death worldwide, and the growing need for replacement vessels is not fully met by autologous grafts or synthetic alternatives. Tissue engineering has emerged as a compelling strategy for the creation of blood vessels for reconstructive surgeries. One promising method to obtain a suitable vessel scaffold is decellularization of donor vascular tissue followed by recellularization with autologous cells. Recellularization of a decellularized scaffold with only a small volume of whole blood was recently presented as a feasible option. We show that, in contrast to the published results, this method fails to re-endothelialize decellularized veins.

• Sundby, Øivind Heiberg; Irgens, Ingebjørg; Høiseth, Lars Øivind; Mathiesen, Iacob; Lundgaard, Eivind & Haugland, Hanne [Show all 10 contributors for this article] (2018). Intermittent mild negative pressure applied to the lower limb in patients with spinal cord injury and chronic lower limb ulcers: A crossover pilot study. Spinal Cord. ISSN 1362-4393. 56, p. 372–381. doi: 10.1038/s41393-018-0080-4. Full text in Research Archive Show summary

  Study design Randomized, assessor-blinded crossover pilot study. Objectives To explore the use of an intermittent negative pressure (INP) device for home use in addition to standard wound care (SWC) for patients with spinal cord injury (SCI) and chronic leg and foot ulcers before conducting a superiority trial. Setting Patient homes and outpatient clinic. Methods A 16-week crossover trial on 9 SCI patients (median age: 57 years, interquartile range [IQR] 52–66), with leg ulcers for 52 of weeks (IQR: 12–82) duration. At baseline, patients were allocated to treatment with INP + SWC or SWC alone. After 8 weeks, the ulcers were evaluated. To assess protocol adherence, the patients were then crossed over to the other group and were evaluated again after another 8 weeks. Lower limb INP treatment consisted of an airtight pressure chamber connected to an INP generator (alternating 10 s −40mmHg/7 s atmospheric pressure) used 2 h/day at home. Ulcer healing was assessed using a photographic wound assessment tool (PWAT) and by measuring changes in wound surface area (WSA). Results Seven of nine recruited patients adhered to a median of 90% (IQR: 80–96) of the prescribed 8-week INP-protocol, and completed the study without side effects. PWAT improvement was observed in 4/4 patients for INP + SWC vs. 2/5 patients for SWC alone (P = 0.13). WSA improved in 3/4 patients allocated to INP + SWC vs. 3/5 patients in SWC alone (P = 0.72). Conclusions INP can be used as a home-based treatment for patients with SCI, and its efficacy should be tested in an adequately sized, preferably multicenter randomized trial.

• Skjørten, Ingunn; Hilde, Janne Mykland; Melsom, Morten Nissen; Hisdal, Jonny; Hansteen, Viggo & Steine, Kjetil [Show all 7 contributors for this article] (2018). Cardiopulmonary exercise test and PaO2 in evaluation of pulmonary hypertension in COPD. The International Journal of Chronic Obstructive Pulmonary Disease. ISSN 1176-9106. 2018:13, p. 91–100. doi: 10.2147/COPD.S150034. Full text in Research Archive Show summary

  Background: Exercise tolerance decreases as COPD progresses. Pulmonary hypertension (PH) is common in COPD and may reduce performance further. COPD patients with and without PH could potentially be identified by cardiopulmonary exercise test (CPET). However, results from previous studies are diverging, and a unified conclusion is missing. We hypothesized that CPET combined with arterial blood gases is useful to discriminate between COPD outpatients with and without PH. Methods: In total, 93 COPD patients were prospectively included. Pulmonary function tests, right heart catheterization, and CPET with blood gases were performed. The patients were divided, by mean pulmonary artery pressure, into COPD-noPH (<25 mmHg) and COPD-PH (≥25 mmHg) groups. Linear mixed models (LMMs) were fitted to estimate differences when repeated measurements during the course of exercise were considered and adjusted for gender, age, and airway obstruction. Results: Ventilatory and/or hypoxemic limitation was the dominant cause of exercise termination. In LMM analyses, significant differences between COPD-noPH and COPD-PH were observed for PaO2, SaO2, PaCO2, ventilation, respiratory frequency, and heart rate. PaO2 <61 mmHg (8.1 kPa) during unloaded pedaling, the only load level achieved by all the patients, predicted PH with a sensitivity of 86% and a specificity of 78%. Conclusion: During CPET, low exercise performance and PaO2 strongly indicated PH in COPD patients.

• Svanteson, Mona; Rollefstad, Silvia Christin Hellerud; Kløw, Nils-Einar; Hisdal, Jonny; Ikdahl, Eirik & Semb, Anne Grete [Show all 7 contributors for this article] (2017). Associations between coronary and carotid artery atherosclerosis in patients with inflammatory joint diseases. RMD Open. 3(2). doi: 10.1136/rmdopen-2017-000544. Full text in Research Archive
• Sundby, Øivind Heiberg; Høiseth, Lars Øivind; Irgens, Ingebjørg; Mathiesen, Iacob; Lundgaard, Eivind & Haugland, Hanne [Show all 10 contributors for this article] (2017). Intermittent negative pressure applied to the lower limb increases foot macrocirculatory and microcirculatory blood flow pulsatility in people with spinal cord injury. Spinal Cord. ISSN 1362-4393. p. 1–10. doi: 10.1038/s41393-017-0049-8. Full text in Research Archive

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• Torbjørnsen, Sara Stadskleiv; Lie, Sole Lindvåg; Rehn, Marius; Hisdal, Jonny & Høiseth, Lars Øivind (2025). Protocol for a randomized crossover study of thigh cuff inflation in experimental hemorrhage: Assessing its potential as a model for zone 3 REBOA. doi: 10.1371/journal.pone.0327404. Full text in Research Archive Show summary

  Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method to provide temporary control of noncompressible torso hemorrhage in trauma patients. Previous research on REBOA has mainly focused on animals and patients. This study aims to explore whether thigh cuff inflation combined with simulated hemorrhage can serve as an experimental human model for zone 3 REBOA. Lower body negative pressure is a model of hypovolemia. A zone 3 REBOA occludes aorta at its bifurcation, essentially excluding the pelvis and lower extremities from the circulation. Bilateral proximal thigh cuffs will occlude blood vessels to and from the lower extremities. Twenty healthy volunteers will be exposed to bilateral proximal thigh cuff inflation to suprasystolic pressures to simulate the hemodynamic effects of REBOA during experimental hemorrhage using lower body negative pressure (LBNP). Each participant will complete two experimental conditions in a randomized order within one study visit. In the one condition, subjects will undergo only 60 mmHg LBNP for six minutes. In the alternate condition, 60 mmHg LBNP will be applied for six minutes, adding thigh cuff inflation during the final three minutes. Continuous, non-invasive monitoring of systemic hemodynamic parameters—including arterial blood pressure, stroke volume, and heart rate—will be conducted. Cerebral hemodynamics will be assessed by measuring middle cerebral artery blood velocity and cerebral oxygenation. Pain related to thigh cuff inflation will be assessed using a verbal numerical rating scale. The impact of thigh cuff inflation on systemic and cerebral hemodynamics will be evaluated using mixed-effects regression modeling. This study aims to examine the systemic and cerebral hemodynamic effects of combined thigh cuff inflation and lower body negative pressure in healthy volunteers. Based on the feasibility and findings, the potential of this combination as a model for zone 3 REBOA in simulated hemorrhage will be discussed.

• Hove, Christine; Sæter, Frode Wirum; Stepanov, Alexey; Bøtker-Rasmussen, Kasper; Seeberg, Trine Margrethe & Westgaard, Espen [Show all 10 contributors for this article] (2025). A prototype photoplethysmography-based cuffless device shows promising results in tracking changes in blood pressure - conference presentation. Full text in Research Archive
• Hove, Christine; Sæter, Frode Wirum; Stepanov, Alexey; Bøtke-Rasmussen, Kasper Gade; Seeberg, Trine Margrethe & Westgaard, Espen [Show all 10 contributors for this article] (2024). EVALUATION OF A PROTOTYPE CUFFLESS MULTI-SENSOR DEVICE TO TRACK BLOOD PRESSURE CHANGES. Full text in Research Archive
• Morton, William James; Hauge, Anton; Opdahl, Helge; Rein, Erling Bekkestad; Søvik, Signe & Hisdal, Jonny (2024). Nine treatments of 1000 mL therapeutic phlebotomy in a subject with polycythemia: A case report. Physiological Reports. 12(11), p. 1–5. doi: 10.14814/phy2.16035. Full text in Research Archive Show summary

  Large-volume therapeutic phlebotomy is the mainstay of hemochromatosis treatment and offers an opportunity to investigate the hemodynamic changes during acute hypovolemia. An otherwise healthy 64-year-old male with hemochromatosis participated. On nine separate visits, 1000 mL therapeutic phlebotomy was performed. On one occasion, pre- and post-phlebotomy orthostatic challenge with 27° reverse Trendelenburg position was administered. Mean arterial pressure, heart rate, and stroke volume were measured continuously during the procedures. The patient's tolerance to the interventions was continuously evaluated. The procedures were well tolerated by the patient. Mean arterial pressure was maintained during hemorrhage and following phlebotomy in both supine and reverse Trendelenburg positions, primarily through an increase in heart rate and systemic vascular resistance. The present study found that 1000 mL therapeutic phlebotomy in a patient with hemochromatosis may be acceptably and safely used to model hemorrhage. The approach demonstrates high clinical applicability and ethically robustness in comparison with volunteer studies.

• Melsom, Helene Støle; Randa, Anders; Hisdal, Jonny; Stang, Julie & Stensrud, Trine (2022). Prevalence of asthma among Norwegian elite athletes. Full text in Research Archive
• Lie, Sole Lindvåg; Hisdal, Jonny; Rehn, Marius & Høiseth, Lars Øivind (2022). Effects of supplemental oxygen on systemic and cerebral hemodynamics in experimental hypovolemia: Protocol for a randomized, double blinded crossover study. PLOS ONE. 17(6). doi: 10.1371/journal.pone.0270598. Full text in Research Archive Show summary

  Supplemental oxygen is widely administered in trauma patients, often leading to hyperoxia. However, the clinical evidence for providing supplemental oxygen in all trauma patients is scarce, and hyperoxia has been found to increase mortality in some patient populations. Hypovolemia is a common finding in trauma patients, which affects many hemodynamic parameters, but little is known about how supplemental oxygen affects systemic and cerebral hemodynamics during hypovolemia. We therefore plan to conduct an experimental, randomized, double blinded crossover study to investigate the effect of 100% oxygen compared to room air delivered by a face mask with reservoir on systemic and cerebral hemodynamics during simulated hypovolemia in the lower body negative pressure model in 15 healthy volunteers. We will measure cardiac output, stroke volume, blood pressure, middle cerebral artery velocity and tolerance to hypovolemia continuously in all subjects at two visits to investigate whether oxygen affects the cardiovascular response to simulated hypovolemia. The effect of oxygen on the outcome variables will be analyzed with mixed linear regression. Trial registration: The study is registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT, registration number 2021-003238-35).

• Hoel, Henrik & Hisdal, Jonny (2021). The FlowOx device for the treatment of peripheral artery disease: current status and future prospects. Expert Review of Medical Devices. ISSN 1743-4440. 18(3), p. 217–220. doi: 10.1080/17434440.2021.1895750. Full text in Research Archive
• Wang, Eivind; Hisdal, Jonny & Solberg, Trine (2021). Ekspertens effektive råd: – Gjør dette to ganger i uka, så vil du se utrolig effekt på kort tid. [Journal]. iharstad.no. Full text in Research Archive
• Wang, Eivind; Hisdal, Jonny & Solberg, Trine (2021). Ekspert mener mange lurer seg selv - slik går du deg sprek. [Journal]. Nettavisen Pluss. Full text in Research Archive
• Melau, Jørgen; Bonnevie-Svendsen, Martin; Mathiassen, Maria; Hilde, Janne Mykland; Oma, Lars & Hisdal, Jonny (2019). Late-presenting swimming-induced pulmonary edema: A case report series from the norseman xtreme triathlon. Sports. 7(6). doi: 10.3390/sports7060137. Full text in Research Archive Show summary

  Swimming-induced pulmonary edema (SIPE) may develop during strenuous physical exertion in water. This case series reports on three cases of suspected late-presenting SIPE during the Norseman Xtreme Triathlon. A 30-year-old male professional (PRO) triathlete, a 40-year-old female AGE GROUP triathlete and a 34-year-old male AGE GROUP triathlete presented with shortness of breath, chest tightness and coughing up pink sputum during the last part of the bike phase. All three athletes reported an improvement in breathing during the first major uphill of the bike phase and increasing symptoms during the downhill. The PRO athlete had a thoracic computed tomography, and the scan showed bilateral ground glass opacity in the peripheral lungs. The male AGE GROUP athlete had a normal chest x-ray. Both athletes were admitted for further observation and discharged from hospital the following day, with complete regression of symptoms. The female athlete recovered quickly following pre-hospital oxygen treatment. Non-cardiogenic pulmonary edema associated with endurance sports is rare but potentially very dangerous. Knowledge and awareness of possible risk factors and symptoms are essential, and the results presented in this report emphasize the importance of being aware of the possible delayed development of symptoms. To determine the presence of pulmonary edema elicited by strenuous exercise, equipment for measuring oxygen saturation should be available for the medical staff on site.

• Johnsen, Lydia; Hisdal, Jonny; Jonung, Torbjörn; Braaten, Audun Ole & Pedersen, Gustav (2019). 3D Ultralyd volum og konvensjonell ultralyd dimeterendringer er likeverdige markører for endolekkasje i oppfølging etter EVAR. Full text in Research Archive
• Bø, Elisabeth & Hisdal, Jonny (2018). Endovaskulær behandling etterfulgt av trening for perifer arteriell sirkulasjonssvikt - Langtidsoppfølging av en randomisert kontrollert studie. Full text in Research Archive
• Johnsen, Lydia; Hisdal, Jonny; Jonung, Torbjörn; Braaten, Audun Ole; Laxdal, Elin Hanna & Kjøsnes, Thomas [Show all 7 contributors for this article] (2017). Contrast Enhanced Ultrasound Detects Endoleak in follow-up after EVAR. Full text in Research Archive
• Hagum, Cathrine Nyhus; Shalfawi, Shaher Ahmmad Ibrahim; Tønnessen, Espen & Hisdal, Jonny (2024). The transition into Norwegian sports High Schools: Measures to optimise student athlete management and development. Universitetet i Stavanger. ISSN 9788284392370. Full text in Research Archive Show summary

  Background: The thesis addresses student athletes attending the optional program subject Elite Sport in Norwegian high schools. The context for the thesis is related to the increasing literature showing the challenges associated with student athletes combining sports and education. Aims: The overall aim of the thesis was to empirically increase our understanding of student athletes attending Norwegian sports high schools and identify possible measures that can be implemented to optimise the combination of sports and education in student athletes. Three separate studies had specific aims subordinated to the overall aim. The knowledge derived from the thesis can hopefully inform future measures to facilitate good experiences in school, sports and life for student athletes and ensure optimal student athlete management and development. Methodology: The thesis had a quantitative approach, and the three substudies investigated three different samples in Norwegian sports high schools. Study Ⅰ and Ⅱ had a cross-sectional design, whereas Study Ⅲ was a randomised controlled trial. The statistical methods applied were primarily structural equation modelling (SEM) in Mplus and general linear model (GLM) in SPSS. This included confirmatory analysis (CFA), exploratory factor analysis (EFA), analysis of variance (ANOVA), multivariate analyses of variance (MANOVA) and chisquare (χ2) test. The data from the three sub-studies are the basis of four separate papers presented in this thesis. In addition to the four papers, the thesis consists of a synopsis that further elaborates the thesis’s position in the research field and the underlying theoretical stance. The synopsis further describes the alignment and consistency between the theoretical stance and the thesis’s approach, design, methods, instruments, and statistical analyses. A discussion of the implications of the study’s main findings, limitations and opportunities for further research is also included in the synopsis. Results: In Paper Ⅰ, the main aim was to translate a questionnaire measuring training distress in athletes and examine its factorial validity. The results showed that the questionnaire could be considered an accepted psychometric tool with some modifications. In Paper Ⅱ, the main aim was to describe training volume and training distress in student athletes studying Elite Sport. The results showed differences in training volume for sports, but not for gender, school year and program. Girls experienced more physical and psychological training distress than boys. Results showed differences in perceived physical and psychological training distress between school years with different training volumes. Paper Ⅲ examined perceived relationships and communication (relational coordination) within and between student athletes, club coaches, school coaches, schoolteachers, parents, and health personnel. The results showed that student athletes, club coaches, and school coaches perceived moderate to weak relational coordination with parents, schoolteachers, and health personnel. Student athletes’ relational coordination score with parents was the only strong score observed. Furthermore, the results reveal notable differences in student athletes’ relational coordination with the roles according to their characteristics. Paper Ⅳ investigated the effect of communication and coordination combined with a progressive and individualised sport-specific training program to reduce all-complaint injuries in student athletes transitioning to a high school sports academy. The results indicated a significant between-group difference in injuries, where the control group had 1.8 times higher injury risk than the experimental group following enrolment. Conclusion: The knowledge generated via this thesis can be used to inform future measures that aim to enhance the combination of sports and education in student athletes for optimal development. In summary, this thesis highlights a holistic view of student athletes and suggests that those involved with the student athletes should consider the whole picture, including physiological, psychological, biomechanical, and other life factors, for optimal student athlete management and development. Regular monitoring over time using an electronic diary available for all the roles involved with the student athlete can have educational purposes and help school coaches and club coaches to track student athletes’ training load, training distress stress and injury status. High-quality relationships and communication between all of the involved roles are vital components for optimal development of student athletes. A particular focus should be on critical transitional phases, such as transitioning from middle to high school. Close follow-up during such periods can contribute to a safer transition to the increased demands student athletes face after enrolment to an elite sports high school.

• Johnsen, Lydia; Hisdal, Jonny; Jonung, Torbjörn & Pedersen, Gustav (2021). Ultrasound in follow-up after endovascular aneurysm repair. Universitetet i Bergen. ISSN 9788230858776. Full text in Research Archive

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