Meditate.

 Deepak Chopra, M.D., the world’s foremost expert on the mind-body connection, states in his book Ageless Body, Timeless Mind that studies have shown that long-term meditators can have a biological age between 5 and 12 years younger than their chronological age.  Levels of the stress hormones cortisol and adrenaline are often found to be lower in long term meditators, and their coping mechanisms tend to be stronger than average.