Exercise Is Critical, Study Suggests
This from http://psychology.about.com/
Past research has shown plenty of great reasons to stay physically fit. Aside from being good for your physical health, regular exercise has been shown to be good for your brain. Some research shows that it might even make you smarter. And, as if you needed one more reason to hit the gym, one study has shown that being fit can help minimize the inevitable brain shrinkage that stems from the aging process.
Full about education article: What Can You Do to Prevent Your Brain From Shrinking As You Age?