Marathon running can damage a heart

Running 26.2 miles is not for the faint of heart.

Abnormalities in heart structure and function were found in men and women who ran the Boston Marathon in 2004 and 2005 by Harvard Medical School researchers.

For some 2,500 years, scientists have written about possible unhealthy outcomes of running for tens of miles when nothing is chasing you. But more and more people are doing it. In 2005, 382,000 runners completed a marathon, 80,000 more than in 2000. That has not led to a massive increase in heart attacks. In fact, Arthur Siegel, an assistant clinical professor of medicine, says the risk of dying from a heart attack is a scant one in 50,000 runners.

Still, through the ages, scientists have worried about, and actually found evidence for, disheartening damage from such exertion. This concern motivated Malissa Wood, a cardiologist at Harvard-affiliated Massachusetts General Hospital, to lead a study to get some better answers to the vexing question. "To our knowledge, our study is the first to successfully correlate participation in endurance sports with evidence of cardiac injury and dysfunction after marathon running," she notes.

Wood has first-leg knowledge of what she studies. She has completed four marathons, covering the 26.2 miles in as little as three hours and 46 minutes.

Wood, Siegel, Tomas Neilan, and their colleagues at Harvard and Duke university teaching hospitals recruited 60 marathoners with no history of heart disease. Forty-one men and 19 women kept logs of their training schedule starting four months prior to the race. They also submitted to blood tests and sound imaging (echocardiography) to determine the before-and-after health of their hearts. They ran the 26.2 miles in times ranging from about three to six hours; the average time was four hours and five minutes.