Exercise and Your Brain

By Barbara C. Bourassa

You know your muscles need exercise to stay toned, as does your heart. But did you know that physical exercise also benefits your brain?

Cardiovascular exercise is considered one of four pillars of good brain health, in addition to good nutrition, stress management, and mental exercise. If you follow this prescription now, you may have a good chance of delaying such age-related brain maladies as dementia, Alzheimer's, and poor short-term memory, brain experts say.

For starters, it helps to understand what, exactly, happens to the brain during aging. "As we age, some areas of the brain get strengthened while others get weakened," says Alvaro Fernandez, CEO and cofounder of Sharp Brains (www.sharpbrains.com), an online fitness center, of sorts, for the brain. "Some functions get better, such as pattern recognition, emotional regulation, and vocabulary, while others typically decline (short-term memory, problem solving, and flexibility)." This theory is referred to as "cells that fire together wire together," meaning that as we age, the things we do more often become hardwired, while the areas we don't use as often decline, he explains.

The four pillars for maintaining good brain health and offsetting the effects of aging work as follows, says Fernandez. Physical exercise can help increase neuron, or brain cell, creation. Stress management helps offset the effects of stress hormones such as cortisol, which kill neurons and/or slow neuron creation. Mental exercises help influence where the new neurons go in the brain and how long they survive. And good nutrition provides the basic nutrients for all these processes to happen, says Fernandez.

Mental exercise also helps create more connections between neurons, and the more connections the better, says Fernandez. "Alzheimer's kills the connections between the neurons, in turn causing the neurons to die by declining oxygen, the life force of brain cells," he says. This is why many researchers are studying how mental exercises, such as puzzles, can possibly delay or prevent dementia.

One of the largest studies concerning brain stimulation and Alzheimer's took place in the 1990s at a convent in Minnesota. The nuns at the convent donated their brains to science, and upon examination, researchers were intrigued by what they found. "The brains without Alzheimer's were more dense and had more neurons and connections than the other brains," says Fernandez. "The researchers also saw that the lifestyle of the nuns without Alzheimer's were more mentally rich, with more stimulation such as playing chess and gardening."

Research showing how physical exercise benefits the brain is much newer. In a study published in the November 2006 issue of the Journal of Gerontology: Medical Sciences, Arthur F. Kramer and his colleagues at the University of Illinois at Urbana-Champaign revealed that moderate exercise increases brain volume in older adults.

The study put sedentary adults ages 60 to 79 in a six-month exercise program that met three times each week. Half of the participants did aerobic exercises such as walking, while the other half did non-aerobic stretching and toning exercises. By the end of the six-month program, the aerobic participants had more brain volume than their counterparts. In addition, the prefrontal and temporal cortices, the areas of the brain where age-related decline often occurs, had the greatest gains from aerobic exercise.

"Moderate levels of exercise—in particular, walking—are relatively easy to do and may result in increased cognitive flexibility and the ability to lead independent lives for longer periods of time," said Kramer in a prepared statement. "You don't have to be a marathon runner. Swimming, biking, and walking are all ways that people can get these anti-aging brain benefits."

Another new study conducted by researchers at the Medical College of Georgia in Augusta found that children who play vigorously for 20 to 40 minutes a day may be more well organized and better at learning math. "Time spent being physically active enhances, rather than detracts, from learning," said Catherine Davis, M.D., in a prepared statement about the results, which were presented at an annual meeting of the Obesity Society in November.

More specific information—such as how long you should exercise and how often—are newer questions that researchers are just beginning to answer, Fernandez says. "Cardiovascular exercise is best, as it brings more oxygen to the brain, and we think that people should exercise two or three times a week, for 20 to 30 minutes per session. Weight training, on the other hand, doesn't appear to have much effect."

As for mental exercise, Fernandez notes, "There is no specific prescription, but researchers do know that novelty is good for the brain, variety is good for the brain, and talent, or pushing yourself to the limit and getting better at something, is good for the brain."

There are a growing number of computer-based tools designed for exercising the brain, some of which can be found on www.sharpbrains.com.