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.

Doing very hard exercise — like sprinting or intense cycling — is linked to more calcium buildup and plaque in the heart arteries, even if the total amount of exercise is the same as someone who exercises less intensely.

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.

Men who have trained for decades in marathons and endurance sports are more likely to have calcium deposits in their heart arteries than men who don't exercise much—even if they're otherwise healthy and have no heart disease risk factors.

For older male athletes who exercise a lot, doing very hard workouts (like sprinting or intense cycling) seems to be linked to more calcium buildup in the heart arteries over time, while moderate hard workouts might not have the same effect.

For older male athletes, doing a lot of hard but not extreme exercise—like fast running or cycling—seems to be linked to less calcium buildup in heart arteries over time, compared to doing super intense workouts.