VERY relative. I'm in my mid-50's and before I got hurt in 2003, I didn't feel old (except when I got up at 0230 with 4 hours of sleep...and had done it 6 days a week for the past 6 months...THEN I felt old enough to fart dust) but since I got hurt, the body FEELS and acts old...
(I had one guy explain, "When you're young, you think you're bullet-proof and shake off minor injuries, but as you get older, you realize those "bullets" actually penetrated and did damage, and you start to feel every one." The older I get, the more I agree with that.
When I was young, 30 was old...till I hit 30 and my wife rented me a wheel chair to go to birthday parties. (new year's eve parties) Then 45 was the "new old"...till I hit 45. Then, I said old is 65...and the closer I get, the more I think I'm right...
