The Potential Cardiac Dangers of Extreme Exercise – Calcium Score Scans show higher plaque volumes

The Potential Cardiac Dangers of Extreme Exercise

Runners during the 2015 New York City Marathon on Sunday. ENLARGE

Runners during the 2015 New York City Marathon on Sunday. Photo: Peter J. Smith for The Wall Street Journal


Kevin Helliker

Updated Nov. 4, 2015 7:00 p.m. ET

A new study finds that exercise that is extreme in either volume or intensity may be associated with high levels of atherosclerosis in the coronary arteries. 

The study, presented in August at a meeting of the European Society of Cardiology, studied 169 veteran competitive endurance athletes against a control group of 171 relatively sedentary subjects. Compared with the control group, the study found lower levels of coronary artery calcium in athletes who ran fewer than 35 miles a week or cycled fewer than 150 kilometers a week. But athletes who ran or cycled beyond that threshold were found to harbor higher levels of coronary artery calcium than did the control group. 

The study, conducted by British physicians, is certain to intensify debate over one of the most controversial questions in modern medicine: Can people exercise too much? By all accounts, exercise lowers blood pressure, helps preserve coronary-artery integrity, lengthens lifespans and otherwise promotes physical and mental health. Exercise is medicine, say public health officials.

But unlike other medication, which is generally prescribed in scientifically determined doses, exercise typically receives a blanket more-is-better recommendation. “Most health benefits occur with at least 150 minutes (2 hours and 30 minutes) a week of moderate intensity physical activity, such as brisk walking,” says a U.S. exercise guideline. It adds: “Additional benefits occur with more physical activity.”

Now, a small but growing number of studies suggest that the benefits of exercise may diminish or even disappear beyond a point. Some evidence suggests that the longevity benefits of endurance exercise may disappear for some extreme athletes. Other evidence shows higher-than-expected coronary artery calcification in such athletes.