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Sunday 28 February 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.

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.

A commonly held view is that adverse clinical events in athletes are explained by exercise acting as a trigger in individuals who are susceptible because of an underlying abnormality. Dr. La Gerche excludes inherited conditions from this discussion, focusing instead on whether exercise may affect a change in the heart that may serve as a cause of arrhythmias in its own right. He reviews the following emerging controversies:


Linda said...

Wow, everything is bad for you! But this correlates to some past stories of health-conscious runners who collapsed and died.

Linda Kay said...

I have a friend whose husband was an avid exerciser. He was even very critical with everyone who carried a little extra weight and didn't go to the gym. He went to bed one night and never woke up, dead at 66. She is struggling.

chris c said...

"definitive media-grabbing statements"

lovely phrase!

Mark Sisson (Mark's Daily Apple), an ex-athlete, nails it when he says

"Move slowly a lot, run very fast occasionally, lift heavy things"

pretty much what we evolved to do.

Would be interesting to see what the effect of diet is in these incidences of exercise-induced problems. Many/most "healthy" people eat low fat diets by default but there are increasing numbers of athletes of all kinds and members of the fitness community who are following research into low carb high fat nutrition, even some entire teams. Probably doing the wrong kind of exercise while eating the wrong diet doubles the problems.