I'm 67 and recently upped my workout from about 6 hrs a week to 9. I'm learning that I feel better (and sleep better) the more exercise I do. In the back of my mind are the Jim Fixxes and Peter O'Toole's quote "the only exercise I get is being pall-bearer at funerals of friends who exercise". My inflammation numbers, etc are good and I recently added protein shakes, as seniors are supposed to gain more muscle mass. There are some cautions, however, about too much protein (hard on kidneys, may promote inflammation). I'm trying to keep exercise within the "doing what one likes, within social context" (currently swim 3x, walk daily, lift/row 3x w). I suppose that when it becomes an obsession it may be counterproductive, but I'm beginning to wonder "could one exercise away the aging process" as I feel as good as ever, mentally sharp, no joint pain, energetic.