The Potential Cardiotoxic Effects of Exercise.

The emerging controversy related to the potential cardiotoxic effects of high doses of intense exercise need to be considered among the much stronger evidence that supports the pleomorphic benefits of exercise as a whole. However, there is fairly compelling evidence to support the association between long-term sport practice and an increased prevalence of atrial fibrillation and the fact that this relates to a chronic altered atrial substrate. This article was designed to challenge the reader with speculative science that suggests that exercise might promote permanent structural changes in the myocardium which can, in some individuals, predispose to arrhythmias. In terms of long-term health outcomes, it would seem that these small risks are outweighed by the many other benefits of exercise, including a likely decrease in atherosclerotic vascular events, although some recent results have brought into question whether the protective benefits of exercise on vascular events also extends to high-intensity exercise training. Above all else, in this article we sought to highlight current controversies to stimulate research on the many unanswered questions. In particular, there is a lack of adequately powered prospective studies from which we can measure health outcomes and their relationship to exercise-induced cardiac remodelling.