Key Points
- Cardiovascular risk mitigation strategies such as the recommendation to engage in a more active lifestyle are common in primary care and cardiovascular clinics, yet more nuanced data gauging the association between lifelong endurance exercise and coronary atherosclerosis is lacking
- In this study, investigators examined the association between lifelong endurance exercise with the incidence of coronary plaque as compared to late-onset endurance exercise and a non-athletic lifestyle
- The study showed that lifelong endurance sport participation was not associated with a more favorable coronary plaque composition; however, this group was found to have less vulnerable plaque as assessed by coronary computed tomography
Motivated patients commonly seek ways to improve their cardiovascular risk profile and many engage in a physically active lifestyle. For those willing and able to participate in more demanding activity, precise data gauging the association between endurance exercise and coronary atherosclerosis is lacking, especially in lifelong athletes. Importantly, current evidence suggests a plaque paradox in the lifelong endurance athlete, where higher degrees of activity long term have been associated with higher coronary artery calcium scores on computed tomography despite the known benefits of exercise in cardiovascular risk mitigation. In this study titled Lifelong Endurance Exercise And Its Relationship With Coronary Atherosclerosis, or the MASTER@HEART trial, investigators sought to probe this paradox by examining whether lifelong endurance exercise was associated with more coronary atherosclerosis as compared to late-onset endurance exercise and a non-athletic lifestyle. It was hypothesized that lifelong endurance athletes would have a lower prevalence of non-calcified plaques compared to non-athletes.
The MASTER@HEART study was a multicenter prospective cohort study including 601 male individuals, between 45 and 70 years old, with at least 6 month of endurance training (>9 hours/week cycling or >6 hours/week running) or no endurance training (3 hours or less a week( and no cardiovascular risk factors. Patients were then divided into three groups based on activity level. The group of lifelong endurance athletes had been involved in endurance training (≥8 hours/week of cycling or ≥6 hours/week of running) before the age of 30 years. This group had 191 patients included. Late-onset endurance athletes were similar to the previous group except they had started endurance training after the age of 30; this included 191 patients. The third group were regarded as the control group and comprised of healthy, non-athletes (≤3 hours/week of activity) and included 176 patients. Exclusion criteria for all groups included a history of smoking (> 5 pack years), diabetes, BMI > 27.2 kg/m2, use of a statin, or use of anti-hypertensives. According to investigators, the study did not include female athletes given the much lower prevalence of ischemic heart disease amongst female athletes. The primary endpoint was the prevalence of coronary plaques (calcified, mixed, and non-calcified) as assessed by coronary computed tomography. The three groups had no significant differences with regard to age, blood pressure, HbA1c, LDL-C. As expected, lifelong and late-onset athletes had significantly lower body fat percentages and measured VO2 levels.
The median number of plaques per individual and average CAC scores were similar between groups, but comparing lifelong athletes directly with controls showed higher CAC percentile in the lifelong athlete cohort. Furthermore, there was no difference in plaque types between groups, a finding that had not been directly explored previously. Analyzing each plaque type, investigators found that participation in lifelong endurance sports was associated with having ≥1 coronary plaque (odds ratio [OR] 1.86, 95% confidence interval [CI] 1.17–2.94), ≥1 proximal plaque (OR 1.96, 95% CI 1.24–3.11), ≥1 calcified plaque (OR 1.58, 95% CI 1.01–2.49), ≥1 calcified proximal plaque (OR 2.07, 95% CI 1.28–3.35), ≥1 non-calcified plaque (OR 1.95, 95% CI 1.12–3.40), ≥1 non-calcified proximal plaque (OR 2.80, 95% CI 1.39–5.65) and ≥1 mixed plaque (OR 1.78, 95% CI 1.06–2.99) as compared to a healthy non-athletic lifestyle. In trying to reconcile these findings, investigators turned to looking at other plaque features, finding that the prevalence of vulnerable plaques, which carry the highest risk for cardiac events, were uncommon in all groups but a lifelong athletic lifestyle was associated with a lower prevalence (OR 0.11, 95% CI 21 0.01 – 0.98).
Investigators concluded that lifelong endurance sport participation along with a healthy lifestyle was not associated with a more favorable coronary plaque composition. Also highlighted was the fact that although a higher burden of plaque was observed in athletes, the burden overall remained low (did not extend beyond SSS >10 or SIS >6). When discussing the implications of the study, presenter Dr. Ruben De Bosscher remarked that the results suggest there might be a “point of diminishing returns” with regard to exercise and coronary artery calcification, proposing that a dose-response relationship between endurance training and coronary atherosclerosis “may be reverse J-shaped”. Importantly, as emphasized in the published manuscript, current evidence cannot relate an increased risk of ischemic heart disease events in endurance athletes. The results of this trial remind providers and patients that the effects of exercise and coronary artery disease are indeed nuanced and a “more is more” approach to exercise now does not guarantee an absence of disease later. It will be interesting to see these how these findings play out longitudinally, particularly with respect to the risk of cardiovascular events in those engaging in long-term, high intensity exercise.
