High Levels of Exercise May Be Cardiotoxic
Benefits of exercise may not extend to high-level training that induces changes in cardiac morphology
TUESDAY, March 1, 2016 (HealthDay News) -- Emerging evidence suggests that there may be some cardiotoxicity associated with exercise, according to a review published online Feb. 24 in the Canadian Journal of Cardiology.
André La Gerche, M.D., Ph.D., from the Baker IDI Heart and Diabetes Institute in Melbourne, Australia, discusses whether exercise could promote permanent structural change in the myocardium, which may predispose some individuals to arrhythmias.
Noting that the benefits of exercise are most clearly established for low and moderate intensities, La Gerche states that these benefits can not necessarily be generalized to high-level training that induces cardiac morphology changes. Increasingly convincing evidence suggests that long-standing endurance training might promote some cardiac arrhythmias, with most studies showing a correlation between atrial fibrillation in middle-aged men and previous endurance sport participation. Fewer data link athletic training with other cardiac arrhythmias. However, in some predisposed individuals, endurance exercise is associated with increased propensity to arrhythmias. Many of the controversies raised are based on small cross-sectional cohort and mechanistic studies.
"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," La Gerche writes.