INDIANAPOLIS (WISH) — When it comes to exercise, can you have too much of a good thing?

The Centers for Disease Control and Prevention recommends 150 minutes of moderately intense exercise and two days of muscle strengthening each week.

But what about those who take their workouts to the next level? Doctors say it could actually have a negative impact on their heart.

Dr. Pamela Rama, a preventative cardiologist at Baptist Health in Jacksonville, Florida, says in recent years, there has been a slight increase in atrial fibrillation in endurance athletes who might swim, ski, or run marathons, as they get to middle age.

Atrial fibrillation, or AFib, is an abnormal heart rhythm. A healthy heart beats 60 to 100 times per minute.
A heart with AFib can beat 140, 170, or even 190 times a minute.

Research has found that years of heavy training may contribute to an increased risk of developing AFib.

“The problem with atrial fibrillation is it puts you at risk for having a stroke because (your heart has such a) disorganized rhythm,” Rama said.

The reason? Over time, exertion not only strengthens our hearts but remodels it.

“The atrial fibrillation is generated from the left atrium (of the heart). And so, when you have a remodeling of that, it makes the left atrium a little bit bigger. You might form some scar tissue and it makes them more prone to having atrial fibrillation,” Rama said.

A study published in the Clinical Journal of Sports Medicine found that out of 942 long-time endurance athletes, 20% – almost all middle-aged men – had AFib, 3% percent suffered a stroke, and swimmers were at a higher risk for AFib.

But doctors warn not to overreact – this isn’t an excuse not to exercise. “Low to moderate intensity exercise is always good for you, and actually, it reduces your risk of atrial fibrillation,” Rama said.

It is recommended to pay attention to sudden heart palpitations or shortness of breath, especially during exercise and if someone experiences unexplained declines in athletic performance.

This story was created from a script aired on WISH-TV. Health Spotlight is presented by Community Health Network.