Evidence continues to pour in on the importance of moderate exercise as we age.

From the Wall Street Journal article:

For the first time, scientists have found something that not only halts the brain shrinkage that starts in a person’s 40s, especially in regions responsible for memory and higher cognition, but actually reverses it: aerobic exercise. As little as three hours a week of brisk walking — no Stairmaster required — apparently increases blood flow to the brain and triggers biochemical changes that increase production of new brain neurons.