Why too much running is bad for your heart

It’s common knowledge that running is one of the most efficient forms of exercise. Many people enjoy running, myself included, and it’s proven that aerobic exercise is good for the heart.

But is it possible to run too much?

I’ve completed 54 marathons during my lifetime, including one in every state. But in 2012, new research about how running marathons affects your heart convinced me to stop. As a cardiologist, I knew my heart health had to come first.

The truth about running is that it is indeed good for your heart — to a point.

From couch potatoes to marathon runners, how running impacts your heart

If a heart attack occurs, a marathon runner is more likely to survive than his or her sedentary counterpart, but the same can be said of people who engage in other kinds of regular activity. Exercising regularly puts your heart in a better place to survive a cardiac event.

But endurance running has actually been linked to poor heart health. Studies have found that the hearts of lifelong male endurance athletes may contain more plaque or other signs of heart problems, such as scarring and inflammation, than the hearts of less active men of the same age.

So, while running marathons may give you a better chance at surviving a heart attack, it’s not going to prevent one, and it may actually increase your risk of having one.

Marathon runners increased risk of heart attack

About 25 percent of the population may be at risk for a condition known as runner’s cardiomyopathy.

For these people, the right atrium and right ventricle dilate and there are elevations of blood troponins and B-type natriuretic peptide, suggesting there is temporary injury to these chambers at the end of a marathon. This is due to three to five hours of volume overload for these thinner chambers while the individual is running a marathon.

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When this damage occurs repetitively over time, scar tissue may build up in the heart muscle, which can lead to sudden death. Marathon runner’s cardiomyopathy is not related to age, gender, degree of conditioning or speed. Thus, the only way to know if you’re at risk is to undergo a cardiac MRI and or have blood tests at the end of a race.

The right amount of running

A combination of both aerobic exercise and strength exercise is best. Exercise helps preserve weight loss, which is good for the heart. Exercise doesn’t prevent plaque buildup or heart blockages, but it does work to make us “tougher” and more likely to survive serious medical illnesses and accidents.

Running is the most efficient source of aerobic exercise, hence its popularity. But only to a certain point. Approximately 15-20 miles per week appears to be ideal — shorter distances and varying speeds are healthier for your heart than endurance running.

Learn more about how much exercise is best for your heart.

Concerned about your heart health? Find the heart care you need today.

About the author

Peter McCullough, MD
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Peter McCullough, MD, is the Chief of Cardiovascular Research at Baylor Heart and Vascular Institute. He helps lead the team of world-renowned cardiologists affiliated with the Institute and with Baylor Hamilton Heart and Vascular Hospital. Dr. McCullough is a graduate of Baylor University. He received his medical degree from the University of Texas Health Science Center at Dallas, Southwestern Medical School in 1988. He completed an internal medicine residency at the University of Washington School of Medicine and, in 1994, a Master in Public Health degree from the University of Michigan School of Public Health. He also completed a three-year fellowship in cardiovascular diseases at William Beaumont Hospital in Michigan.

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Why too much running is bad for your heart