Athletes who train a lot have plaque, but it’s hard and rock-like, so it doesn’t break off and cause heart attacks like softer plaque does.

High-intensity endurance exercise, when accumulated over long durations, is associated with a significantly increased prevalence of coronary artery plaque, an association not detected using self-reported exercise metrics.

High-volume, high-intensity endurance exercise increases coronary artery plaque burden without increasing all-cause or cardiovascular mortality risk in otherwise healthy individuals.

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 athletes are super fit, their heart plaques aren’t more stable or ‘safer’ than those of healthy non-athletes—so being an elite athlete doesn’t make plaque less dangerous.

Even though super-fit people have more calcium in their heart arteries, they still live longer and have fewer heart attacks — their fitness seems to protect them from the danger of the plaque.