I'm 50ish.

Yea, I notice a difference. I don't recuperate as quickly nor do I heal as quickly. I take vitamins and anti-oxidants. The only thing I can say for sure is Glucosamine with Chondroiton really does work for me and helps my back.

Sometimes it's depressing knowing that no matter how much I train I'll never be as good as I was when I was 35...but that's life and you learn to maximize what God gives you.