Those two-a-days may not be so good for you, according to a new study
You know by now that over-exercising is not only dangerous, but could a sign of exercise bulimia, a Diagnostic and Statistical Manual of Mental Disorders-verified disease. (That's doctor speak for a legitimate psychiatric condition.) That means no exercising to the point of nausea, fainting, exhaustion, illness—you get the picture. So if you're occasionally guilty of pulling two-a-day workouts, you seriously might want to stop: An extensive review of studies to be published in the April issue of the Canadian Journal of Cardiology has found that intense exercise (read: vigorous, high-intensity, endurance stuff) can cause irreparable structural heart damage through an increased risk of atrial fibrillations (or AFib). (Watch out for these 5 Telltale Signs You're Exercising Too Much.)
Lead researcher Dr. Andre La Garche, M.D., Ph.D., and head of Sports Cardiology at Baker IDI Heart and Diabetes Institute in Melbourne, Australia, and his team reviewed 12 different studies on abnormal heart rhythms in athletes and endurance runners. Specifically, the studies focused on arrhythmia known as AFib, which ultimately can lead to stroke or complete heart failure. La Gerche's team found an undeniable correlation between the two, including in a 2011 study of his own that looked at AFib in those who didn't previously suffer from heart disease, and found that those patients were four times as likely to have engaged in endurance sports.
Wait. Don't cancel your next marathon just yet. The review specifically cites that the benefits of exercise far outweigh the risks—and what's more, the exercise not only needs to be a vigorous effort, but rather a sustained and vigorous one too. (P.S. You don't actually have to run very far to reap the benefits of running.) In the piece, extreme exercise is considered to consist several hours of vigorous exercise nearly every single day—what you'd maybe see from a pro, but not an everyday yoga class habit.
However, La Garche says there is not really enough research as to be able to define a specific point at which risk of AFib skyrockets (say, five hours of running every day—oy), and that more studies are needed. Which was the exact reason for his review—to "discuss 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," he said in a statement. Furthermore, it's that same exact reason La Garche is citing in the need for more research.
Until then, though, maybe just stick to a healthy exercise regimen. How much that is, though, totally depends on your goals. We'd suggest trying our 30-Day Burpee Challenge or this Kickass New Boxing Workout.