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Why Fitness is Still A Health ‘Bargain,’ Despite Study Linking Extreme Exercise, Heart Disease

February 18, 2019

In the category of “too much of a good thing can be bad,” the results of a large-scale study published recently in the Journal of the American Medical Association Cardiology indicate that too much exercise might strain or harm the heart of some athletes.

Yet Dr. Paul Thompson, director of research with the Hartford HealthCare Heart & Vascular Institute and chief of cardiology emeritus for Hartford Hospital, said there’s no reason to hang up the running shoes or swim goggles just yet. More research, he said, is needed to qualify the type of person who could be affected by extreme forms of exercise — marathons and other endurance sports – eyed in the JAMA article.

“There’s increased evidence that a lot of exercise can increase cardio calcification in more active people who did not have active calcifications already,” Dr. Thompson said, noting that calcifications made up of plaque can clog the arteries and become life-threatening as they impede blood flow to the body and brain. “Everyone says these are stable calcifications that won’t rupture and cause issues, but I am not convinced that is the case yet.  I think we will find that there is more plaque in general in these people, but we need more research to be certain.”

The study mentioned in JAMA was conducted by scientists at the Cooper Institute in Dallas and other sites across the country and looked specifically at the impact of extreme exercise in 21,758 middle-aged male athletes. They formed three groups based on the amount the men exercised and compared scans of each man’s heart for plaque accumulation, while tracking public records over a decade in search of any premature deaths among the men.

The study noted that while those men in the highest exercise group tended to have more plaque in their arteries, they were still less likely than more sedentary people of the same age to die prematurely of any cause, including a heart attack.

This seems counter to research indicating that people who meet the federal exercise recommendations of 30 minutes a day of moderate activity enjoy a reduced risk of developing heart disease. The Cooper researchers suggested that extreme athletes have a different, more protective type of plaque developing in their hearts that does not tend to break off in the bloodstream and cause life-threatening problems.

“Let’s face it,” Dr. Thompson said, “exercise is the best bargain in public health. Is there such a thing as too much? I’m not sure, but I wouldn’t advise people to stop. I’d say people should exercise because they like it, though, and not be convinced that they have to do more and more and more to become healthier.”

Some previous studies have shown that the hearts of lifelong endurance athletes such as marathon runners show scarring in the heart muscles and larger deposits of coronary artery plaque, Dr. Thompson noted that more research on this topic is needed before we can decide whether these changes are deleterious or a benign finding.

“Medicine is really a pendulum,” he said. “You think something is really good, then some evidence suggests that a technique, drug or lifestyle is actually really bad. The truth is often somewhere in the middle.”

For more information on Hartford HealthCare’s Athlete’s Heart program, founded by Dr. Paul Thompson, click here.