Stronger, Faster, Smarter. By: Carmichael, Mary, Newsweek, 00289604, 3/26/2007, Vol. 149, Issue 13
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Stronger, Faster, Smarter
Section: Health for Life
Exercise does more than build muscles and help prevent heart disease. New science shows that it also boosts brainpower--and may offer hope in the battle against Alzheimer's.
The stereotype of the "dumb jock" has never sounded right to Charles Hillman. A jock himself, he plays hockey four times a week, but when he isn't body-checking his opponents on the ice, he's giving his mind a comparable workout in his neuroscience and kinesiology lab at ...view middle of the document...
Other scientists have found that vigorous exercise can cause older nerve cells to form dense, interconnected webs that make the brain run faster and more efficiently. And there are clues that physical activity can stave off the beginnings of Alzheimer's disease, ADHD and other cognitive disorders. No matter your age, it seems, a strong, active body is crucial for building a strong, active mind.
Scientists have always suspected as much, although they have not been able to prove it. The idea of the "scholar-athlete" isn't just a marketing ploy dreamed up by the NCAA; it goes back to the culture of ancient Greece, in which "fitness was almost as important as learning itself," says Harvard psychiatrist John Ratey. The Greeks, he adds, were clued into "the mind-body connection." And they probably intuited a basic principle that Western researchers also figured out long ago: aerobic exercise helps the heart pump more blood to the brain, along with the rest of the body. More blood means more oxygen, and thus better-nourished brain cells. For decades, that has been the only link between athletic and mental prowess that science has been able to demonstrate with any degree of certainty. "People have been slow to grasp that exercise can really affect cognition," says Hillman, "just as it affects muscles."
Now, however, armed with brain-scanning tools and a sophisticated understanding of biochemistry, researchers are realizing that the mental effects of exercise are far more profound and complex than they once thought. The process starts in the muscles. Every time a bicep or quad contracts and releases, it sends out chemicals, including a protein called IGF-1 that travels through the bloodstream, across the blood-brain barrier and into the brain itself. There, IGF-1 takes on the role of foreman in the body's neurotransmitter factory. It issues orders to ramp up production of several chemicals, including one called brain-derived neurotrophic factor, or BDNF. Ratey, author of the upcoming book "Spark: The Revolutionary New Science of Exercise and the Brain," calls this molecule "Miracle-Gro for the brain." It fuels almost all the activities that lead to higher thought.
With regular exercise, the body builds up its levels of BDNF, and the brain's nerve cells start to branch out, join together and communicate with each other in new ways. This is the process that underlies learning: every change in the junctions between brain cells signifies a new fact or skill that's been picked up and stowed away for future use. BDNF makes that process possible. Brains with more of it have a greater capacity for knowledge. On the other hand, says UCLA neuroscientist Fernando GÃ³mez-Pinilla, a brain that's low on BDNF shuts itself off to new information. In his experiments, rats were put through weeks of running on a wheel, a workout that increased their BDNF levels. GÃ³mez-Pinilla left half of the animals alone; in the other half, he blocked the chemical's effects with a...