ironman triathlons

As polio makes a comeback, Minda Dentler reflects on her life with the disease. Paralyzed as an infant in India, she's gone on to become a champion wheelchair triathlete and an immunization advocate.

Research finds that triathletes who train too hard can impair a brain area involved in achieving goals such as winning a race. Fatigued athletes choose immediate gratification over long-term rewards.

The 63-year-old Libertarian presidential nominee has run 17 marathons and four Ironman Triathlons. He doesn't drink or smoke cigarettes, though his doctor doesn't address his past marijuana use.