With the Boston Marathon approaching the front end of the nation's radar, there are more than a few running-related stories swirling about in the Google's news health section. One of the more interesting ones pointed to the seemingly backwards finding that high volume/lifelong runners are more at risk for heart disease than sedentary individuals, the Australian reported.

The body of research supporting the link between running and heart disease, however, is small, as the Australian pointed out. Not all cardiologists believe it.

"The science establishing a causal link between vigorous exercise and coronary disease is shaky at best," Aaron Baggish of Massachusetts General told the Australian.

Peter McCulloguh, a cardiologist at Baylor University who published a recent study on the phenomenon, believes in the evidence.

"Studies support a potential increased risk of coronary artery disease, myocardial fibrosis and sudden cardiac death in marathoners," McCullough wrote in the current Missouri Medicine.

One of the problems relates to diet. Because high level endurance athletes expend significantly more calories than the average person, they justify less than heart-healthy foods -- even if they're mixing in a solid dose of fruits, vegetables, and the like. Boston Marathon director Dave McGillivray, who was recently diagnosed with a heart condition, once typified such a lifestyle.

"I figured if the furnace was hot enough, it would burn everything," he said of his eating habits.

Some doctors at the more extreme end of the spectrum even believe long term endurance exercise too greatly taxes the heart. Most doctors who are open to the correlation between running and heart danger, however, believe exercise can and should be maintained among older runners with a heart condition as long as they seek treatment.