Tony Horton, creator of home workout P90X, was diagnosed with a rare neurological disorder. Now, he is fitter than ever at 66, thanks to his new diet and workouts.

When Horton's creation, P90X, hit the fitness industry in 2005, it became a smash hit. The program sold more than 3.5 million copies thanks to its high-intensity blend of circuit-style training ...

P90X trainer Tony Horton is in the best shape of his life at 66. Here are his top longevity tips.