Study findings are a bit counterintuitive. Although atherosclerosis burden was higher in highly active middle-aged men, actual atherosclerosis disease was less due to structure and composition of plaques. “Exercise” plaques are mostly calcified, thus more stable and less likely to rupture, causing fewer acute coronary events.

Circulation

Observational Study

April 2017

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 CVD 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 non-contrast and contrast-enhanced CT 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-min/week. Participants were categorized as <1000 MET-min/week, 1000-2000 MET-min/week or >2000 MET-min/week.

Results: 284 men (55±7 years) were included. Coronary artery calcification was present in 150/284 (53%) participants with a median CAC-score of 35.8 [9.3-145.8]. Athletes with a lifelong exercise VOLUME >2000 MET-min/week (n=75) had a significantly higher CAC-score (9.4 vs. 0, p=.02) and prevalence of coronary artery calcification (68%) and plaque (77%) compared to <1000 MET-min/week (n=88, 43% and 56% respectively).

Very vigorous INTENSITY exercise (≥9 METs) was associated with coronary artery calcification (OR=1.47) and plaque (OR=1.56). Among participants with CAC>0, there was no difference in CAC-score (p=.20), area (p=.21), density (p=.25) and regions of interest (p=.20) across exercise volume groups.

Among participants with plaque, the most active group (>2000 MET-min/week) had a lower prevalence of MIXED plaques (48% versus 69%, OR=0.35) and more often had ONLY calcified plaques (38% versus 16%, OR=3.57) compared to the least active group (<1000 MET-min/week).

Conclusions: Participants in the >2000 MET-min/week group had a higher prevalence of coronary artery calcification and atherosclerotic plaques. The most active group did however have 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.