The older you get the truer the principle, "Use it or lose it." Also, with age, all of your parts go off warranty. Don't forget, all the abuses of your youth catch up with you, the more of them there are/were, the worse it is. The meaning of "extreme" sports means just that--extreme debility later on in life with each accumulated crash & burn. I'm extremely active and agile at 56, but things break easier, take longer to heal, and that's after living a life of eating well, staying in shape, and STILL never having broken a bone or undergone any major surgery.
Do not live your life short-sighted, nor take for granted the principle "garbage in/garbage out". That covers all aspects of life from food/friends/environment/spirituality, etc. Treat your "vehicle" with great respect--you only get one at-bat.