Studies get closer to understanding how exercise benefits the Brain

A recent article from the New York Times Health Section by GRETCHEN REYNOLDS  outlines how recent studies have new evidence that short bursts of intense exercise may increase a  protein known as brain-derived neurotrophic factor, or BDNF, in the brain.  BDNF is known to promote the health of nerve cells in the brain.   One recent study in Ireland suggests that increases in BDNF prompted by exercise may play a particular role in improving memory and recall. 
Reynolds article went on to describe a recent experiment involving aging pilots. "The experiment, published last month in the journal Translational Psychiatry, scientists at Stanford University School of Medicine asked 144 experienced pilots ages 40 to 65 to operate a cockpit simulator three separate times over the course of two years. For all of the pilots, performance declined somewhat as the years passed. A similar decline with age is common in all of us. Many people find it more difficult to perform skilled tasks — driving an automobile, for instance –  as they grow older, says Dr. Ahmad Salehi, an associate professor of psychiatry and behavioral sciences at Stanford and lead author of the study. "

" These aging pilots carried a common genetic variation that is believed to reduce BDNF activity in their brains. The men with a genetic tendency toward lower BDNF levels seemed to lose their ability to perform complicated tasks at almost double the rate of the men without the variation.

While the pilot experiment wasn’t an exercise study, it does raise the question of whether strenuous exercise could slow such declines by raising BDNF levels, thereby salvaging our ability to perform skilled manual tasks well past middle age.

“So many studies have shown that exercise increases levels of BDNF,” says Dr. Salehi. While he notes that other growth factors and body chemicals are “upregulated” by exercise, he believes BDNF holds the most promise.

“The one factor that shows the fastest, most consistent and greatest response is BDNF,” he says. “It seems to be key to maintaining not just memory but skilled task performance.”

Dr. Salehi plans next to examine the exercise histories of the pilots, to see whether those with the gene variant, which is common among people of European or Asian backgrounds, respond differently to workouts.

In people who have the variant and less BDNF activity, “exercise is probably even more important,” he says. “But for everyone, the evidence is very, very strong that physical activity will increase BDNF levels and improve cognitive health."

http://well.blogs.nytimes.com/2011/11/30/how-exercise-benefits-the-brain/?smid=tw-nytimeshealth&seid=auto