Marathoners, Train to Protect Your Heart

Runners cross the Verrazano Bridge at the start of the New York City Marathon, November 6, 2011. Credit: Emmanuel Dunand / AFP / Getty Images

If you're planning on running your very first marathon, you're probably expecting to feel a bit sore the following morning. As it turns out, not only do your muscles get tired during a marathon, your heart does as well, according to a new study published in the 'Canadian Journal of Cardiology.'

"Like any other muscle in the body, the heart gets tired due to sustained activity," says Dr. Aaron Baggish, associate director of the Cardiovascular Performance Program at Massachusetts General Hospital Heart Center. But there's some good news, too. The study analyzed 20 recreational marathon runners and showed that logging in some extra, prerace miles helps mitigate some of these effects. "The more training you do and the more miles you run, the less likely you are to have this process of cardiac fatigue," says Baggish.

The takeaway: The more time and energy you put into preparing for a race, the better. "That includes more miles, more race simulation, and longer runs that approximate the marathon distance," he says.

Although the heart muscles of runners studied showed full recovery within six to eight weeks, doing a similarly prolonged strenuous activity (such as running another marathon) within that time period may increase the risk of a cardiac event. So make sure to give yourself ample time to recover.