Bigger hearts don’t necessarily signal a bigger problem

The average American will never have Olympic-level athletic ability—but they could have an Olympian-sized heart.

“Athlete’s heart” is a documented phenomenon in which the hearts of endurance athletes become enlarged in response to high levels of exercise. Aware of the condition, physicians are careful not to misdiagnose athletes with heart disease, which is a potential cause of an enlarged heart.

According to a study published by the MRC Science Centre based at Imperial College London, the same enlarged heart is possible in average adults who exercise moderately. The study of 1000 people found that one third of participants who exercised three or more hours a week developed an enlarged heart, while almost half of those who exercised five or more hours a week exhibited such a symptom.

The findings suggest that the more exercise a person performs, the more pronounced the effect on the heart’s structure, regardless of athletic ability.

“Going to the gym frequently increases the thickness of your heart muscle and the volume of your heart chambers, particularly the right ventricle,” lead scientist Declan O’Regan said in a statement. “It’s a completely normal, healthy response. It shouldn’t be misdiagnosed as being heart disease.”

More muscle and greater blood flow means greater efficiency. However, if one of these changes were to happen independently, it would signal a problem. For that reason, in addition to taking note of a patient’s height, weight and gender, a physician should also ask about activity levels in order to avoid misdiagnosis.