The longer a man has trained for marathons, the more likely he is to have serious artery blockages—even if he’s otherwise healthy, with no high cholesterol or blood pressure.

Even though endurance athletes have less dangerous plaque overall, about 1 in 6 still have a major blockage in their heart arteries — meaning exercise doesn’t completely prevent heart disease.

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.

Men who train extremely hard for endurance sports like marathons or triathlons for many years tend to have more calcium buildup in their heart arteries than men who exercise moderately, even though they’re otherwise healthy.

Even after accounting for things like cholesterol and blood pressure, the more hours someone spends training over the year, the more likely they are to have plaque in their heart arteries.

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.