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 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 [OR _adjusted ]=3.2; 95% confidence interval [CI], 1.6–6.6) and plaque (77%; OR _adjusted =3.3; 95% CI, 1.6–7.1) compared with 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%; OR _adjusted =0.35; 95% CI, 0.15–0.85) and more often had only calcified plaques (38% versus 16%; OR _adjusted =3.57; 95% CI, 1.28–9.97) compared with the least active group (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.

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.

To investigate the physiological adaptation of the right ventricle (RV) in response to endurance training and to define reference values for regional deformation in the RV in endurance athletes. Healthy controls (n = 61), athletes (n = 58), and elite athletes (n = 63) were prospectively enrolled with a training intensity of 2.2 ± 1.6, 12.5 ± 2.3 and 24.2 ± 5.7 h/week, respectively (P < 0.001). Conventional echocardiographic parameters, tissue Doppler imaging (TDI), and 2D strain echo (2DSE)-derived velocity, strain, and strain rate (SR) were calculated in three RV segments. Left ventricular and RV dimensions were significantly increased (P < 0.001) in both groups of athletes compared with controls. Right ventricular systolic velocities and displacement were not different between the groups. Right ventricular strain and SR values were reduced in the RV basal and mid-segment in athletes. Athletes with marked RV dilatation showed lower strain and SR values in the basal (−20.9 ± 4.7 vs. −24.5 ± 4.9%, P < 0.001 and −1.23 ± 0.31 vs. −1.50 ± 0.33 s⁻¹, P < 0.001) and mid (−29.3 ± 5.4 vs. −32.1 ± 5.3%, P = 0.017 and −1.58 ± 0.41 vs. −1.82 ± 0.42 s⁻¹, P = 0.009) segment, whereas athletes without RV dilatation showed no significant difference compared with the controls. Regional deformation and deformation rates (TDI and 2DSE) are reduced in the basal RV segment in athletes. This phenomenon is most pronounced in athletes with RV dilatation and should be interpreted as normal when evaluating athletes suspected for RV pathology.

To establish cardiac MRI reference values for endurance athletes and nonathletes, and study the impact of variables related to ventricular volumes and wall-mass. Three hundred and thirty-six prospectively recruited healthy individuals aged 18-39 years (mean age 26+/-6 years, 46% women) underwent cardiac MRI: 79 elite athletes (exercising >18 h/week), 143 regular athletes (9-18 h/week), and 114 matched nonathletes (< or =3 h/week). Body surface area corrected right (RV) and left ventricular (LV) end-diastolic volume (EDV ml/m2) and wall mass (g/m2) were significantly higher (P<0.0005) in regular/elite athletes than in nonathletes (nonathlete/regular-athlete/elite-athlete; men RV-EDV 111/136/144, RV-wall mass 12/14/15, LV-EDV 101/123/129, LV-wall mass 48/62/69; women RV-EDV 96/115/118, RV-wall mass 10/13/14, LV-EDV 90/107/107, LV-wall mass 34/46/50). Male sex, body surface area, and training hours/week increase ventricular volume and wall mass. In elite athletes, short-axis RV diameter exceeded 50 mm in 49/16% (men/women), and LV diameter exceeded 60 mm in 55/16% (men/women). Interventricular septal-wall thickness was 13-15 mm in 5% regular and 15% elite male athletes. Cardiac MRI reference values show increased ventricular volumes, diameters, wall mass, and wall thickness for endurance athletes compared with nonathletes. High training hours/week and male sex result in an increased overlap with standard thresholds for cardiomyopathy. To help prevent inconclusive reports, the 95th percentile reference values can be used as an alternative to standard upper limits used for the general population.