Abstract 19302: Long Term High Endurance Exercise and the Heart: Too Much of a Good Thing?

Abstract

Introduction: The benefits of regular moderate exercise are well documented, however, there is a burgeoning group of veteran athletes who have been exercising vigorously since youth and the impact of life long intensive exercise on the heart is unknown. Hypothesis: Life-long intensive exercise may promote adverse cardiac remodelling. Methods: A large cohort of veteran athletes and gender, age and Framingham matched controls were studied comprehensively to investigate any detrimental effects of chronic life-long intensive exercise among veteran athletes. Veteran athletes were defined as >40 years of age and having competed in multiple endurance events over a 10 year period. Controls were recruited from University staff. All individuals were subjected to a cardiopulmonary exercise test, 24 hour Holter monitor, cardiac MRI (CMR) and CT coronary angiography. Results: A total of a 178 veteran athletes (m=128 f=50, mean age:54.8) and 123 controls (m=75 f=48, mean age 55.3) were recruited. Athletes demonstrated enlargement of all chamber sizes compared to sedentary controls on CMR. A significant proportion of male athletes (17.5%) exhibited myocardial fibrosis compared to none of the sedentary men (p=0.008) although this difference wasn’t observed in females (2.5% vs 0%, p=1.0). In 45% of cases fibrosis was subendocardial in distribution suggesting a prior ischaemic event. Male athletes with myocardial fibrosis had a 15% prevalence of ventricular tachycardia on a 24hour ECG compared to 1.06% of fibrosis free athletes (p=0.017). Compared to controls, male athletes had a higher prevalence of atherosclerosis (28.2% ≥2vessel disease vs 3.45%, p=0.009). Female athletes had similar indices of atherosclerosis compared to controls but they did demonstrate a U shaped relationship between V02 max and atherosclerosis: The lower and upper tertile of V02 Max had a higher prevalence of atherosclerosis (20%, and 26.7%) than those in the middle tertile(6.7%). Conclusions: Long term endurance exercise is associated with adverse cardiac remodelling. Myocardial fibrosis is common in male veteran athletes and is associated with ventricular tachycardia. Chronic endurance exercise also promotes atherosclerosis in males and females and this is likely to be dose dependent.