At 40, I still work out, not so serious about it any more, just had a lay-off of a couple of years, longest I have had since I was about 20 I think, hard getting going again, and like another poster said, injuries start piling up as you get older, my left shoulder is fucked and so is my lower back, you just learn to manage as best you can, gets harder to get in great shape and staying consistent can be tough also. But I always feel better when weight training is part of my life, over the years I have had long breaks from training only to eventually feel like shit and gravitate towards the gym again. I suppose for me it's about the only thing I don't mind doing that keeps me on an even keel.