Trial Lecture – time and place
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Adjudication committee
- First opponent: Professor Maja-Lisa Løchen, Department of Community Medicine, The Arctic University of Norway
- Second opponent: Senior Consultant Tor Ole Klemsdal, Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital
- Third member and chair of the evaluation committee: Professor Torgeir Bruun Wyller, Faculty of Medicine, University of Oslo
Chair of the Defence
Associate Professor Aud Høieggen, Faculty of Medicine, University of Oslo
Principal Supervisor
Senior Consultant Per Torger Skretteberg, Oslo University Hospital
Summary
Background: Cardiovascular disease (CVD) is still the leading cause of mortality in the world, and more targeted prediction models are needed to improve CVD prevention.
Aims: We hypothesized that heart rate reserve (difference between maximal heart rate and resting heart rate), temporal change in the chronotropic index ([achieved maximal heart rate – resting heart rate]/[estimated maximal heart rate – resting heart rate]), and physical fitness influenced long-term risks of CVD and CVD-related mortality. We also hypothesized that physical fitness had limited durability as a CVD risk predictor.
Methods: Heart rate reserve, chronotropic index, and physical fitness were measured at two examinations, seven years apart, after symptom-limited bicycle ECG exercise tests of 2014 healthy middle-aged men in the 1970s. End-points were collected from scrutiny of hospital charts and the Norwegian Cause of Death Registry after 35 years of follow-up. Cox proportional hazard regression models adjusted for age and classical CVD risk factors were used to estimate risks.
Results: Heart rate reserve was an independent predictor of CVD death. We found an interaction between heart rate reserve and physical fitness and after stratification by physical fitness level; the predictive abilities of heart rate reserve were confined to the group of men with low physical fitness. Temporal change in the chronotropic index was an independent predictor of CVD death and all-cause death. Physical fitness was an independent predictor of early CVD death, but the association wakened as time progressed. In contrast, classical CVD risk factors, and change in physical fitness during middle-age impacted CVD death risk in a full lifetime perspective.
Conclusions: The findings presented within this thesis support our hypotheses and indicate that repeated testing of heart rate response during exercise and exercise capacity could strengthen long-term CVD risk assessment.
Additional information
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