Study says 'Fitness Age' a better predictor of longevity

You might think you know exactly how old you are. But you could be wrong.

A new study suggests that a person's so-called fitness age-determined by cardiovascular endurance is a better predictor of longevity than chronological age.

The good news is, unlike the REAL number on your doctor's charts, your fitness age can actually get "younger" over time with regular exercise.