Study finds that running may lead to enlarged aorta

The fact that endurance athletes have larger-than-average hearts has been known for quite some time, and this is a healthy adaptation from regular cardiovascular exercise. Until recently, the thought was that the aorta—the main artery leaving the heart and supplying the body with oxygenated blood—was not affected by this growth. A study out of Massachusetts General Hospital (MGH) found that this is, in fact, not the case, and endurance training can lead to enlarged aortas as well, which some runners might consider to be cause for concern.

Other studies had been conducted regarding the aorta in the past, but they mostly involved young athletes under the age of 25. “These studies found that the aorta’s size wasn’t affected by endurance training,” says Dr. Aaron Baggish, director of the Cardiovascular Performance Program at MGH. Dr. Baggish and his colleagues started to question this as they noticed a high volume of enlarged aortas in masters athletes compared to the non-athlete population.

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The team decided to look into that—specifically with masters athletes—to see if this was the norm, and if so, if enlarged aortas would create problems for these athletes down the road. They looked at 442 endurance athletes between 50 and 75 years old from across the U.S. and found that 25 per cent of them had aortas larger than the upper limit of clinical normality.

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“Young athletes didn’t have enlarged aortas with their enlarged hearts, but that was not the same story with the older athletes,” says Dr. Baggish, who is also the medical director for the Boston Marathon.

@MGHHeartHealth study finds long-term endurance exercise is associated with enlarged aorta https://t.co/l17SBUosc3 #triathlon #marathon #cycling

— MassGeneral News (@MassGeneralNews) February 27, 2020

It’s still unclear whether this is good or bad for athletes. Non-athletic patients with dilated aortas are at increased risk for a leak or rupture, complications which have mortality rates as high as 50 per cent. The next step for the MGH team is to find out if aortic enlargement in athletes will produce the same results as in non-athletes.

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“This observation was an important one to put out there,” says Dr. Baggish, “but now we have an obligation to follow up with these subjects to see in five years if there’s a progression or if anyone’s sick because of it.”