Exercise increases activity in the part of the brain that is central to memory and learning. It is already known that people who take regular exercise do better on memory tests.

Now researchers at Columbia University Medical Center have shown more specifically what impact exercise has on the brain. It appears to target an area called the dentate gyrus within the hippocampus, a region known to be important in memory and learning.

The study is the first ever to reveal neurogenesis, the growth of neurons, within the living brain. Using a magnetic resonance imaging (MRI) method developed at Columbia, the researchers showed that after exercise, there is more neurogenesis in the dentate gyrus. The new study build on previous research in mice, showing that exercise stimulates neurogenesis in the dentate gyrus. It is the first one that shows the same happens in humans. Therefore, there are sound scientific reasons why it's a good idea to get moving if you want to keep your memory active.

Source

Proceedings of the National Academy of Sciences online March 12-17 2007