Exercise Boosts Mind Power, Muscle Power

There are two kinds of good news about brain power: First, you aren't stuck with the number of brain cells you were born with. And second, it isn't true that brain cells will inevitably die off as you age and can never be replaced.

Pumping up your body and mind with extra oxygen from exercise is the magic that gives birth to more brain cells and keeps the ones you already have in top shape. It turns out that aerobic exercise is one key to "getting smart" and staying that way.

Neurologist Fred H. Gage was the first to challenge the "no new brain cells" doctrine. A professor at the Salk Institute in La Jolla, Calif., Gage discovered newborn cells in the brains of terminally ill cancer patients. The new cells appeared in the part of the brain associated with learning and memory.

In further experiments, Gage shows that the number of brain cells in mice will increase too, but only when the mice run. In 1999, he demonstrated that exercising mice had twice as many new brain cells as did mice that didn't.

At the institute for Brain Aging and Dementia at the University of California at Irvine, director Carl Cotman discovered that after workouts, lab animals had far higher levels of neurotrophic factor BDNF, which he calls the brain's wonder drug. He says it's like plant fertilizer. It encourages the growth of brain cells and protects them from injury.

Research with humans seems to support animal studies. A University of Illinois study, for example put healthy older adults to the test. They exercised with three 45-minute walks a week, while others in the study did only stretching and toning. The aerobic volunteers improved performance on cognitive tests by 15 to 20 percent. The stretchers saw no gain.  

Arthur Kramer, who led the Illinois study, says all it takes to generate new cells is an aerobic workout three or four times a week. Jogging, brisk walking, or swimming will do.