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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Ola Hammarsten, University of Gothenburg, Sweden
- Second opponent: Professor Morten Vetrhus, University of Bergen, Norway
- Third member and chair of the evaluation committee: Professor II Siri Rostoft, University of Oslo
Chair of the Defence
Professor II Anners Lerdal, University of Oslo
Principal Supervisor
Professor II Jonny Hisdal, University of Oslo
Summary
This PhD thesis in cardiovascular and sports medicine explores how biomarkers of endothelial function and myocardial injury behave after extreme endurance exercise. The work is based on data collected from presumed healthy adult triathletes participating in the Norseman Xtreme Triathlon between 2018 and 2024.
The main research questions were: 1. How do metabolites related to endothelial nitric oxide (NO) synthesis (L-arginine, ADMA, and SDMA) change following prolonged endurance exercise, and how long do these changes persist? 2. How do cardiac troponin I (cTnI), troponin T (cTnT) and the cTnI/cTnT ratio respond to such exercise?
In a longitudinal field study, blood samples were obtained one to two days before the race, immediately after, the day after, and one week after completion. Serum levels of L-arginine, ADMA, SDMA, cTnI, and cTnT were analyzed, and ratios between L-arginine/ADMA and cTnI/cTnT were calculated.
Results showed a transient reduction in L-arginine and L-arginine/ADMA ratio and a concomitant increase in ADMA and SDMA after the race. These findings suggest a short-lived reduction in substrate availability for endothelial NO synthesis and temporary inhibition of NO production. All parameters normalized or trended strongly towards normalization within one week.
Both cTnI and cTnT rose markedly after the race, with most participants trending towards normalization the day after. However, a subset displayed prolonged elevation and increasing cTnI/cTnT ratios the day after.
In conclusion, biochemical changes after extreme endurance exercise are substantial but reversible. For most athletes, they likely represent physiological stress rather than pathology. However, persistent post-race troponin elevation may warrant further evaluation as a potential screening tool for occult cardiovascular disease in endurance athletes.
Additional information
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