Why Exercise Can Radically Improve Intelligence

In the late 1990s, researchers proved that human and animal brains produce new brain cells, and that exercise increases the process. But precisely exercise affects the intricate workings of your brain at a cellular level has remained mysterious. However, a number of new studies have begun to identify the specific mechanisms, and have raised new questions about just how exercise reshapes your brain.

In some studies, scientists have been manipulating the levels of bone-morphogenetic protein (BMP) in the brains of mice. The more active BMP becomes, the more inactive your brain stem cells become and the fewer new brain cells your produce. Exercise reverses some of the effects of BMP.

According to the New York Times:

“But there are caveats and questions remaining ... BMP signaling was found to be playing a surprising, protective role for the brain’s stem cells ... Without BMP signals to inhibit them, the stem cells began dividing rapidly, producing hordes of new neurons. But over time, they seemed unable to stop, dividing and dividing again until they effectively wore themselves out.”
Sources:
New York Times July 7, 2010