My dad,77 at the time gave me his GT hybrid that he had put 15,000 miles on. He went and got a CD R600 and rode till he was 80. After bypass he was a little iffy so got a specilized hybrid for awhile but had to get back on his CD. Rode 5 to 6 days aweek 30-40 miles.He didnt take anything. He was the same as when he started at 72 or so. Thats all he did,no weights or pushups. The big C got him and i got his bikes but all to small. He's why i ride. He had alot of balls.Had them when he was at Pearl Harbor when they got bombed.