In 2012, Belgian scientists published a study that concluded that repeated bouts of intensive endurance exercise at the elite level may result in the pathological enlargement of the right ventricle, which, according to the article, is associated with potential health hazards including sudden cardiac death. The publication was the cause of considerable debate among experts in the medical and sports communities. Sports medicine physicians have now tested the conclusions of the 2012 study by examining the hearts of elite master endurance athletes. Their findings refute the hypothesis proposed by their Belgian colleagues.

Source: Is endurance training bad for you?