Researchers find heart disease in a marathon runner -- Is too much exercise a bad thing?

Doctors at the University of Maryland Medical Center had a mystery on their hands. A 51-year-old physician colleague who looked the picture of health—no cardiovascular risks, a marathon runner who had exercised vigorously each day for 30 years—had just flunked a calcium screening scan of his heart. The patient had expected a score indicating a healthy cardiovascular system. Instead, the images indicated a high score: a build-up of calcium in his coronary arteries put him at high risk for blocked blood vessels and a possible heart attack.
The mystery was all the more intriguing because his resting blood pressure and fasting cholesterol levels, the usual measures of cardiovascular health, were in the normal range.
In the March 1, 2007, issue of the American Journal of Cardiology, the researchers say this is the first case, to their knowledge, of advanced coronary calcification in an otherwise healthy middle-aged male marathon runner who lacked traditional cardiac risk factors and had no symptoms of heart disease. The researchers conclude that the physician’s intense, long-term exercise regime, coupled with a predisposition toward a type of hypertension, contributed to his cardiovascular disease. "In this particular individual, we think that oxidative stress was an important contributor," says the study’s senior author, Michael Miller, M.D., director of preventive cardiology at the University of Maryland Medical Center and associate professor of medicine at the University of Maryland School of Medicine. "But we also found that this individual has exercise-induced hypertension, which I think is vastly under-diagnosed."

http://www.eurekalert.org/pub_releases/2007-03/uomm-rfh031407.php