A new study published in Mayo Clinic Proceedings finds that heart attack survivors who exercise excessively are at increased risk of dying from heart problems. However, regular physical activity is recommended for managing heart disease and lowering the risk of death from high blood pressure, stroke and type 2 diabetes.

In the new study, researchers from the Department of Cardiology, Hartford Hospital, Hartford, CT, analyzed data from the National Walkers’ and Runners’ Health Studies databases, involving about 2,400 physically active heart attack survivors.

Share on Pinterest According to the Physical Activity Guidelines for Americans, we need about 150 minutes per week of moderate-intensity exercise or 75 minutes per week of vigorous-intensity exercise.

The results confirm previous findings that the benefits to the heart of walking and running are about the same, as long as the energy expended is the same. However, when walking rather than running, it takes about twice as long to burn an equal number of calories.

The study also found that deaths from heart problems decreased up to 65% among patients who ran less than 30 miles per week or walked less than 46 miles per week. Exercising more than this, however, resulted in the benefits of exercise being lost.

The authors explain:

“These analyses provide what is to our knowledge the first data in humans demonstrating a statistically significant increase in cardiovascular risk with the highest levels of exercise.”

“Results suggest that the benefits of running or walking do not accrue indefinitely and that above some level, perhaps 30 miles per week of running, there is a significant increase in risk. Competitive running events also appear to increase the risk of an acute event,” they add.

However, the authors admit that because all of the patients in their study were heart attack patients, it may not be possible to generalize their findings to all heavy exercisers.