Can endurance exercise be too much of a good thing?

You know exercise is good for you. In fact, some studies suggest the more you exercise, the greater the health benefits you’ll reap.

But can you do too much of a good thing? 

A recent report from the American Physiological Society suggests that long-term high-intensity training can potentially damage the heart—but it was also found to prolong life expectancy and decrease the overall risk of cardiovascular mortality. According to Oklahoma Medical Research Foundation President Stephen Prescott, M.D., this report shouldn’t come as much of surprise, nor should it be cause for alarm for the typical gym goer.

“Improving your level of fitness yields a long list of benefits,” said Prescott. “It can lower blood pressure and heart rate, help you maintain a healthy weight, increase your resistance to infections and improve your mental acuity.” 

Prescott, a physician and medical researcher, recommends regular exercise. But before you jump in and tackle a marathon, he suggests you do one important thing first: learn your family’s heart history.

If you have heart issues in your family, he said, you may set yourself up for trouble. In that case, too much strenuous exercise may be damaging to the heart.

The new report, which was published in Physiological Reviews, took a comprehensive look at all of the potential effects intense chronic endurance exercise can have on the heart. Results showed no evidence that a normal, healthy person was in danger. But there was a caveat when it came to lineage.

While frequent exercise is undoubtedly good, Prescott said, it is important to note that intense training causes changes in cardiac structure and function, which is normally good. That said, in some people, these changes can imitate heart damage and may aggravate inherited conditions like cardiomyopathy, a condition resulting in an abnormal heart muscle. It may even mask problems like atherosclerosis, a disease where deadly plaque builds up in the arteries.

“We’ve seen signs for a long time that heart problems can result from excessive exercise,” said Prescott. “You may think you’re doing better by doing more. But your genetic makeup might work against you.”

If your New Year’s resolution was to get in better shape, this shouldn’t raise a red flag so long as you start slowly and increase exercise gradually. Start with low-impact, aerobic exercises like walking, easy jogging, swimming or elliptical training and then work your way up from there.

“Fitness matters, but it’s most important to do it sensibly,” said Prescott. “Don’t try to do every Crossfit challenge your first week back in the gym or try to lift as much weight as the 20-something person across the room. Be smart and protect your heart.”