Another cool post from http://www.runningnetwork.com/. They featured an article from the New York Times on how exercise increases brain activity. The study explained "an expanding body of research shows that exercise can improve the performance of the brain by boosting memory and cognitive processing speed. Exercise can, in fact, create a stronger, faster brain."
The main study discussed in the article focuses on the behavior of mice. However, another study focuses on the behavior of humans, and how change of diet and exercise increased blood flow to key areas of the brain.
So, for anyone out there who tells you running is crazy, you can cheerily come back with "no, running is smart!" And it is.