Neurosurgeon grandfather crushes triathlon at 83. How do you get as fit as he is?

In his 40s, renowned neurosurgeon Dr. Joseph Maroon struggled to climb stairs without accelerating. Today, at 83, he competes in grueling triathlons and shares his secrets to getting and staying in shape.

Having hit rock bottom mentally and physically at the age of 40, a friend encouraged Dr. Maroon to take up running. He started slowly, just trying to go around the track a few times. But he was hooked, both because of how the exercise made him feel physically and because it lifted his spirits and allowed him to sleep again after months of insomnia.

Soon, Dr. Maroon added swimming and cycling to his routine. In 1993, at the age of 53, he completed his first Ironman triathlon, a 2.4-mile swim, a 112-mile bike ride and a full marathon. Now 83, he has completed eight Ironman events and recently finished second in his age group at the National Senior Games.

When asked for advice for younger people who want to get fit in their 40s, 50s, 60s and beyond, Dr. Maroon offered three simple tips:

1. Start with something simple that you enjoy—even just walking. You don't have to train for a triathlon on day one. Build little by little.

2. Add endurance/strength and flexibility such as yoga or pilates. Aerobic exercise alone is not enough with age.

3. Find a balance between work, family, exercise and relaxation. Excessive stress weakens your health.

Dr. Maroon says one run in high school track "saved his life" helping him recover when he felt down and off track.  At the age of 83, he is proof that it's never too late to change your fitness and health. His secret: Start small, mix it up and make self-care a priority. Even the busiest of us can spare 15 to 20 minutes a day for a walk or jog, like the one that got this neurosurgeon's grandfather on the path to elite sport at age 50.