I am almost 73. Up until very recently (I have a nagging GI problem that gives me sporadic fits) I could do 300 continuous (regular, full length) pushups. I have no desire to do 1000 in one day (in groups). 300 contiguous pushups is good enough for me, at my age. I was inspired to achieve this goal by Walt Stullman, a much-loved cardiologist and former colleague at Highland General Hospital (Oakland CA), who also achieved this figure before his passing, several years ago. I strive to stay fit, however, as I have all my life (running, cycling & weights) and at 6 feet height, I maintain my weight at about 158 pounds. The key to maintaining good health (one’s personal genome permitting, of course), in my considered opinion, is combining a healthy (portion-controlled) diet with regular exercise. Seems to work for me. I have no desire to live forever, something we all hear from rah-rah health proponents nearly every day. When it’s time to clock-out, it’s time to clock out; no need to be obsessive about longevity. In fact, God probably has a fully equipped gym and running track up there somewhere, tucked behind the pearly gates (I say that tongue-in-cheek as a very committed non-believer).