Exercise and the heart: the good, the bad, and the ugly

Abstract

The benefits of exercise are irrefutable. Individuals engaging in regular exercise have a favourable cardiovascular risk profile for coronary artery disease and reduce their risk of myocardial infarction by 50%. Exercise promotes longevity of life, reduces the risk of some malignancies, retards the onset of dementia, and is as considered an antidepressant. Most of these benefits are attributable to moderate exercise, whereas athletes perform way beyond the recommended levels of physical activity and constantly push back the frontiers of human endurance. The cardiovascular adaptation for generating a large and sustained increase in cardiac output during prolonged exercise includes a 10-20% increase in cardiac dimensions. In rare instances, these physiological increases in cardiac size overlap with morphologically mild expressions of the primary cardiomyopathies and resolving the diagnostic dilemma can be challenging. Intense exercise may infrequently trigger arrhythmogenic sudden cardiac death in an athlete harbouring asymptomatic cardiac disease. In parallel with the extraordinary athletic milieu of physical performances previously considered unachievable, there is emerging data indicating that long-standing vigorous exercise may be associated with adverse electrical and structural remodelling in otherwise normal hearts. Finally, in the current era of celebrity athletes and lucrative sport contracts, several athletes have succumbed to using performance enhancing agents for su…