Teens who were more aerobically fit had fewer heart arteries with a dangerous mix of soft and hard plaque when they got older.

Boys who were more physically fit at age 18 had a lower chance of having serious clogged heart arteries when they reached their 50s.

Teenage boys who were both strong and fit had the lowest risk of serious heart artery blockages when they became middle-aged.

Being fit as a teen didn’t seem to protect against hardening of the neck arteries when people got older.

Even though super-active athletes have more plaque in their heart arteries, the plaque they have is harder and less dangerous-looking than the softer, riskier kind seen in less active people.

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.