Thirty is just when you start to see some signs of aging try hitting 45 and things really start falling apart. In your thirties you can compensate by taking care of yourself but after 40 you are just plugging holes in a sinking ship. I had to buy reading glasses this year and the hardest part of staying in shape isn't motivation it is injuries. There is a reason so few athletes are still playing at 40 and it isn't just loss of speed.