Exercise and Coronary Atherosclerosis: Observations, Explanations, Relevance, and Clinical Management

Abstract

Physical activity and exercise training are effective strategies for reducing the risk of cardiovascular events, but multiple studies have reported an increased prevalence of coronary atherosclerosis, usually measured as coronary artery calcification, among athletes who are middle-aged and older. Our review of the medical literature demonstrates that the prevalence of coronary artery calcification and atherosclerotic plaques, which are strong predictors for future cardiovascular morbidity and mortality, was higher in athletes compared with controls, and was higher in the most active athletes compared with less active athletes. However, analysis of plaque morphology revealed fewer mixed plaques and more often only calcified plaques among athletes, suggesting a more benign composition of atherosclerotic plaques. This review describes the effects of physical activity and exercise training on coronary atherosclerosis in athletes who are middle-aged and older and aims to contribute to the understanding of the potential adverse effects of the highest doses of exercise training on the coronary arteries. For this purpose, we will review the association between exercise and coronary atherosclerosis measured using computed tomography, discuss the potential underlying mechanisms for exercise-induced coronary atherosclerosis, determine the clinical relevance of coronary atherosclerosis in middle-aged athletes and describe strategies for the clinical management of athletes with coronary atherosclerosis to guide physicians in clinical decision making and treatment of athletes with elevated coronary artery calcification scores.

Keywords: athletes; computed tomography angiography; coronary atherosclerosis; exercise.

Figure 1.

Prevalence of coronary artery calcification in the general population. Studies reporting coronary artery calcification (CAC) prevalence and adjusted odds ratios for the association between physical activity and CAC are shown.^,,, A, Percentage of CAC prevalence (CAC Score [CACS]>0) across physical activity/exercise groups. B, Adjusted odds ratios for CAC prevalence across physical activity/exercise groups. In B, Desai et al (blue color) included 520 men and 259 women, but the sample size per physical activity categories was not reported. In summary, there is no clear net effect toward either a positive or inverse association between physical activity volumes and CAC prevalence in general population studies. MET indicates metabolic equivalent of task; and PA, physical activity.

Figure 2.

Prevalence of coronary artery calcification and coronary artery calcification scores in studies comparing male athletes with controls. A, Prevalence of coronary artery calcification (CAC) scores (CACS) >0 within athletic and control subjects.^– B, Prevalence of CACS >100.^{-, 41} C, CACS within those individuals with prevalent CAC.^– These data illustrate increased CAC in the most active athletes. AU indicates arbitrary units; MET, metabolic equivalent of task; and RF, risk factors.

Figure 3.

Coronary plaque morphology in athletes. Panel A illustrates the percentages of different coronary plaque morphologies of the 99 plaques in athletes and 26 plaques in the control subjects (total equals 100%). Panel B illustrates the percentages of different coronary plaque morphologies in athletes with plaques, presented for lifelong exercise volume groups, whereas Panel C illustrates the percentage of athletes with plaques who had only calcified, only noncalcified or only mixed plaque morphology. Adapted and reprinted with permission from Merghani et al (A) and Aengevaeren et al (B and C). MET indicates metabolic equivalent of task.

Figure 4.

Potential explanations for increased coronary atherosclerosis in athletes.

Figure 5.

The benefits and risks of long-term exercise training on coronary function, morphology, and atherosclerosis.