Background: Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and cardiovascular disease outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis.
Methods: Middle-aged men engaged in competitive or recreational leisure sports underwent a noncontrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by metabolic equivalent of task (MET) scores to calculate MET-minutes per week. Participants' activity was categorized as <1000, 1000 to 2000, or >2000 MET-min/wk.
Results: A total of 284 men (age, 55±7 years) were included. CAC was present in 150 of 284 participants (53%) with a median CAC score of 35.8 (interquartile range, 9.3-145.8). Athletes with a lifelong exercise volume >2000 MET-min/wk (n=75) had a significantly higher CAC score (9.4 [interquartile range, 0-60.9] versus 0 [interquartile range, 0-43.5]; P=0.02) and prevalence of CAC (68%; adjusted odds ratio [ORadjusted]=3.2; 95% confidence interval [CI], 1.6-6.6) and plaque (77%; ORadjusted=3.3; 95% CI, 1.6-7.1) compared with <1000 MET-min/wk (n=88; 43% and 56%, respectively). Very vigorous intensity exercise (≥9 MET) was associated with CAC (ORadjusted=1.47; 95% CI, 1.14-1.91) and plaque (ORadjusted=1.56; 95% CI, 1.17-2.08). Among participants with CAC>0, there was no difference in CAC score (P=0.20), area (P=0.21), density (P=0.25), and regions of interest (P=0.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/wk) had a lower prevalence of mixed plaques (48% versus 69%; ORadjusted=0.35; 95% CI, 0.15-0.85) and more often had only calcified plaques (38% versus 16%; ORadjusted=3.57; 95% CI, 1.28-9.97) compared with the least active group (<1000 MET-min/wk).
Conclusions: Participants in the >2000 MET-min/wk group had a higher prevalence of CAC and atherosclerotic plaques. The most active group, however, had a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants.
Keywords: atherosclerosis; computed tomography angiography; coronary vessels; exercise.
© 2017 American Heart Association, Inc.