Study: How Dangerous It Is to Exercise Too Hard


Of course you know that exercise is absolutely vital to your health, but a growing body of research indicates that there might be a point at which it stops being beneficial—and starts increasing your odds of heart problems or even an early death. The latest research, published in Mayo Clinic Proceedings, suggests that exercising too much may increase your risk of dying from cardiovascular disease.

For the study, researchers looked at data on about 2,400 heart attack survivors who had participated in the National Runner’s and Walker’s Health Studies and assessed whether participants’ exercise habits were linked to mortality. (The reason they looked at heart attack survivors in particular is that there weren’t enough “cardiac events” among the healthy runners to examine the effect of exercise on cardiovascular mortality.) After controlling for factors like sex, age, education, red meat intake, fruit intake, alcohol consumption, baseline smoking status, aspirin use, and medications for high cholesterol, hypertension, and diabetes, researchers found that exercise was inversely correlated with mortality risk—up to a point.

After 10.4 years, 526 of the participants had died—and more than 70 percent of the deaths were related to cardiovascular disease. People who did the exercise equivalent of running 15 to 23 miles per week had a 50 percent lower risk for cardiovascular disease-related mortality than did those who exercised infrequently, whereas those who ran 23 to 30 miles per week decreased their risk by 63 percent. Beyond 30 miles of running or 46 miles of brisk walking per week, though, there was a 2.62-fold increased risk of dying of cardiovascular disease (that’s about the same risk as with the people who didn’t meet the minimum exercise guidelines).

Granted, this research was done on heart attack survivors—for whom it makes sense that pushing themselves too much might be just as harmful as not working out at all. More research needs to be done to see if these results would pan out with a healthy population of study subjects. (It’s worth noting that the relationship between exercise and non-heart disease-related deaths was statistically insignificant in this study.)

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