High levels of intense exercise may be unhealthy for the heart

http://www.eurekalert.org/pub_releases/2016-02/ehs-hlo022416.php

Public Release: 25-Feb-2016
High levels of intense exercise may be unhealthy for the heart
More research needed into the effect of intense exercise on heart structure and function, according to sports cardiologist writing in the Canadian Journal of Cardiology
Elsevier Health Sciences

There is growing evidence that high levels of intense exercise may be cardiotoxic and promote permanent structural changes in the heart, which can, in some individuals, predispose them to experience arrhythmias (abnormal heart rhythm). A review published in the Canadian Journal of Cardiology explores current controversies and makes the case for investing in large prospective research studies into the effect of intense exercise on heart structure and function.

There are unquestionable benefits to "getting off the couch." However, there is already fairly compelling evidence supporting the association between long-term sports practice and increased prevalence of atrial fibrillation, and the fact that this relates to chronic altered atrial substrate. Without challenging the undeniable evidence supporting low and moderate intensity exercise, this review by sports cardiologist André La Gerche, MD, PhD, provides a balanced discussion of the available data for and against the concept that intense exercise, particularly endurance exercise, may cause adverse cardiac changes in some athletes.

"Much of the discussion regarding the relative risks and benefits of long-term endurance sports training is hijacked by definitive media-grabbing statements, which has fueled an environment in which one may be criticized for even questioning the benefits of exercise," explains Dr. La Gerche, who is Head of Sports Cardiology at the Baker IDI Heart and Diabetes Institute, Melbourne, Australia. "This paper discusses the often questionable, incomplete, and controversial science behind the emerging concern that high levels of intense exercise may be associated with some adverse health effects."

As Dr. La Gerche points out, all available therapies, pharmacological or otherwise, have a dose-response relationship whereby benefits diminish at high doses and the risk of adverse events increases. An open mind would consider that this may even be possible for exercise.

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