Exercise affects the brain as well as the body. I've acquired the habit of running around the block 1-2 times per day as a way to get up, get the blood to circulate, and to focus my attention on what I'm working on. It turns out, recent research says this makes me smarter! Especially if I do distance jogging, and I'm a rat.
I'll stick to running around the block.
NYT: Which Type of Exercise Is Best for the Brain?