STEVEN JONAS

79, triathlon, Port Jefferson, N.Y.

As a kid, Jonas had no hand-eye coordination, dooming him to sit out school sports. But in 1980, at age 43, he took up running in an effort to get healthier. Two years later, he entered a 10K, completing it in 44 minutes.

“All of a sudden the light was lit. Here’s this kid who couldn’t do anything now [racing]. When I finished, I cried.” The next year—34 years ago—Jonas entered his first triathlon. He’s now completed 243—and written a book about the sport,

Triathloning for Ordinary Mortals. Jonas continues to compete, and he cycles, runs or swims five to six days a week. “I’m certain that I feel better about myself than anyone who doesn’t exercise. I know what it does for my head and my looks. When my age comes up, people say, ‘Are you really 79?’”

Tip: “Accept that it’s OK to get older. You just do things at a different level. What’s best is whatever helps you get out there five days a week. If you’re not having fun, why do it?”