Running marathons and ultramarathons are often associated with peak cardiovascular fitness. But research examining longtime endurance athletes raises an interesting question: Is there a point where more isn’t always better for the heart?
A 2023 study found that endurance athletes had more coronary plaque than healthy non-athletes. Researchers themselves were surprised by the results, said Brittany M. Owen, MD, an interventional cardiologist at UT Physicians Multispecialty – Cinco Ranch.
The findings don’t prove that endurance exercise causes heart disease. Instead, they suggest there may be more to learn about what happens to the body after years of intense training.
“There may be cause for concern, or at least a need for further investigation into the long-term effects of high-endurance training,” said Owen, an assistant professor of cardiology with McGovern Medical School at UTHealth Houston.
Interpreting the long-term effects
One possible explanation is simple wear and tear. During prolonged training, endurance athletes spend more time with elevated heart rates and blood pressure. Over decades, that may affect the cardiovascular system in ways researchers are still working to understand.
But the physical demands of endurance sports extend beyond the extra miles.
Owen noted that these athletes often consume large amounts of fast-acting carbohydrates during training and competitions. Researchers have questioned whether years of repeated sugar surges may contribute to plaque development. For now, however, there is no clear evidence that those fueling strategies are responsible for the findings.
“Like a lot of things in life, moderation is best,” Owen said. “Anything you do to an extreme normally has effects at some point, even if it’s healthy.”
What the findings don’t mean
Seeing the words “plaque buildup” can sound alarming, but Owen cautions against jumping to conclusions. The body is also highly adaptable. Endurance athletes often develop cardiovascular changes that help them perform at a high level for years. In some cases, those adaptations may allow them to continue exercising without symptoms, even when plaque is present.
“Our bodies are very well designed and can make adjustments,” Owen said. “Just having plaques doesn’t mean that you’re necessarily doomed.”
Researchers also don’t yet know whether plaque in endurance athletes carries the same long-term risk as plaque in more sedentary individuals. The study identified a pattern but did not establish a cause.
“The study just tells us this happens more,” Owen said. “We don’t actually know the cause yet.”
The findings also don’t mean every endurance athlete should rush to schedule a heart scan. While imaging tests can provide useful information, Owen said doctors must consider how the results will actually affect care. For some people, testing may be appropriate based on symptoms, family history, cholesterol levels, or other risk factors. For others, finding plaque might create anxiety without clearly changing treatment decisions.
Finding the sweet spot
For most people, the findings don’t change the basics of heart health. Owen said the standard heart-health recommendations remain a good target.
“The good news is that you don’t need to be training for marathons or ironman races to obtain good heart health,” Owen said. “Being healthy is more attainable than that. A steady routine of 30 minutes of cardio training along with 15–20 minutes of weight training for most days out of a week is enough to prevent heart disease.”
For those just getting started, Owen recommends beginning with small goals and building gradually. A walk around the neighborhood can become a longer walk, then a brisk walk, and eventually a more challenging workout.
Weight training matters, too, she said, because muscles and bones become stronger only when they’re challenged.
Most importantly, people shouldn’t let news about elite endurance athletes make them think meaningful exercise is out of reach.
“The bar isn’t so far away that no one can do it,” Owen said. “It’s actually very attainable. Doing something is better than nothing.”