Marathoners show higher-than-expected heart risks

"Some older marathon runners may have a greater chance of suffering a heart attack than their risk factors belie, new research suggests. In a study of male marathoners age 50 and up, researchers found that, despite their high activity levels, the runners were as likely as other men their age to have calcium buildup in their heart arteries. And when compared with men who had a similar amount of heart disease risk factors, marathoners actually tended to have more calcium in their arteries" - Reuters