The clogs in athletes' arteries are silent — they don’t cause pain or symptoms, and only show up on special scans.

Even though endurance athletes have more fatty deposits in the main heart arteries—especially the soft, unstable kind—they don’t have the dangerous features that usually make plaques burst and cause heart attacks.

The presence of increased coronary artery plaque in high-volume endurance athletes is not associated with a higher incidence of clinical cardiovascular events such as myocardial infarction or cardiac death.

People who train hard and regularly for endurance sports are less likely to have dangerous, unstable plaque in their heart arteries that could suddenly cause a heart attack.

Older athletes who train hard for many years tend to have more calcium deposits and fatty buildups in their heart arteries, but these buildups are usually hard and stable, not soft and dangerous.

Even though elite athletes have more plaque in their hearts, the type of plaque they have is harder and less likely to rupture — which might be why they live longer than you’d expect.