Smart exercise

Researchers found that exercise can help to replenish brain cells in a region of the brain that is linked with the age-related memory decline that begins for most people around age 30.

The study, published in the March 2007 early online edition of Proceedings of the National Academy of Sciences, tested mice to see the effects of exercise on the region of the brain called the dentate gyrus, which is linked to memory and memory loss.

After using MRIs to study the process in mice, researchers at Columbia University then used magnetic resonance imaging scans to compare the brains of people before and after exercise. They found the same patterns -- which suggest that people also grow new brain cells when they exercise.

"No previous research has systematically examined the different regions of the hippocampus and identified which region is most affected by exercise," said Scott Small, M.D., of Columbia University Medical Center and the study's lead author. "I, like many physicians, already encourage my patients to get active and this adds yet another reason to the long list of reasons why exercise is good for overall health."

In addition to MRI scans, researchers also measured the fitness of each participant by measuring oxygen volume before and after the training program.

Exercise generated blood flow to the dentate gyrus region, and the more fit a person got, the more blood flow the MRI detected, the researchers found. It took only three months of exercise for people with low levels of aerobic fitness to increase blood flow to that part of their brain and improve their scores on memory tests.

"Our next step is to identify the exercise regimen that is most beneficial to improve cognition and reduce normal memory loss, so that physicians may be able to prescribe specific types of exercise to improve memory," Dr. Small said in a Columbia news release.