Research in the European Heart Journal suggests that extreme endurance exercise, like training for a marathon, can damage the heart…permanently. 40 athletes were studied (with MRI scans) before their races, immediately afterwards, and then again one week later. Most had stretched heart muscles after the race, and while most made complete recoveries after a week, 5 out of 40 showed more permanent injuries.
Athletes’ hearts had actually changed shape; the right ventricle – one of the four chambers in the heart involved in pumping blood around the body – appeared dilated and didn’t work as well as it had prior to the race. Levels of the chemical BNP, which is made by the heart when it’s put under excessive stretching, were also increased. Researchers say these changes can cause heart problems like arrhythmia.
In fact, while most of the athletes’ hearts returned to normal, 5 of the athletes who actually had been training and competing longer than the others had signs of tissue scarring and further impaired right ventricle functioning.
More research is needed on the topic, but even Sanjay Sharma, medical director of the London Marathon, agrees that marathon training can certainly do damage:
“My personal feeling is that extreme endurance exercise probably does cause damage to the heart in some athletes. I don’t believe that the human body is designed to exercise for as long as 11 hours a day, so damage to the heart is not implausible.”
But remember, physical activity is an important part of a healthy lifestyle with clear health benefits. The athletes in this study were competing in long distance races and events, training for more than 10 hours a week. The average person should aim for 30 minutes a day, or 3-4 hours a week.
Whether you’re training for a marathon or exercising 30 minutes a day, make sure to see your physician before starting an exercise program, and remember to get your annual check-ups!
