Apart from the mental benefits, there is some evidence for organic/physical benefits as well. 

Dean Ornish, the well known cardiologist who helped former U.S. President Clinton with his diet - and the creator of the only FDA approved prescribed and reimbursed diet for cardiac disease, also has done studies on meditation and health. 

He found that telomeres, the ends of chromosomes that slowly get eroded away with aging, actually regrow with meditation. 

It is unclear whether his work has been duplicated elsewhere, but it is a striking and considered highly significant physical finding with implications for health and longevity. It is one of the few actual cellular changes that have been found related to meditation.