HEALTH JOURNAL

Exploring the Bicycle-Brain Connection:
How Exercise Boosts Cognitive Function

By KEVIN HELLIKER
Staff Reporter of THE WALL STREET JOURNAL
August 30, 2005; Page D1

In recent weeks, President Bush's active exercise regimen has come under fire. Lost amid the controversy is a growing body of evidence showing that exercise is good for the brain as well as the body.

Ever since a physical exam in July deemed the 59-year-old president to be extraordinarily fit, a series of columns and cartoons have portrayed him as riding a bike when he ought to be running the country. Adding force to the criticism was a report that the president asked a potential Supreme Court nominee to describe his exercise program.

This criticism would be unimportant if it were merely political. But anyone who works out an hour a day is likely to discover that many people in sedentary America regard exercise as the province of the vain and irresponsible. Those who engage in it are often seen as devoted more to their physiques than to their kids or their careers.

Yet the science behind exercise increasingly shows that it provides a short-term boost to the ability to process data, among other functions. Acute bouts of exercise have also been found to reduce depression and anxiety, illnesses that can dampen mental functioning. Over time, exercise has been shown to help ward off the mental effects of aging, perhaps even Alzheimer's.

Those findings suggest that exercise ought to be prized in any employee whose job requires quick thinking and good judgment. Of course, exercise doesn't guarantee that President Bush or anyone else will make good decisions. "There is no evidence that you are wiser if you are physically active," says Rod K. Dishman, a professor of exercise science at the University of Georgia.

Still, a flurry of studies has shown a link between exercise and mental performance. A 2005 study in the Journal of Exercise Physiology looked at how 884,715 fifth-, seventh- and ninth-graders scored on a state-mandated fitness test in California. Then it compared those numbers to the reading and math performance of those students on a standardized achievement test.

Guess what? The fittest students had the best test scores. For example, the average math score of students who achieved only three of six fitness goals was 48; kids who achieve all six fitness goals had an average math score of 60.

"Results indicate a consistent positive relationship between overall fitness and academic achievement," said the study. "As overall fitness scores improved, mean achievement scores also improved."

Of course, no researcher is suggesting that exercise can replace intellectual exertion. Rather, it can enhance it.

That effect can be quick. A 2003 article in the journal Acta Psychologica analyzed dozens of studies on the short-term cognitive consequences of exercise. "The empirical data provide compelling support for the view that aerobic exercise can facilitate cognitive functioning," specifically information processing, concluded the article, called "The Effects of Acute Bouts of Exercise on Cognition."

For some exercisers, the cognitive benefits often arrive even before the workout is over. When author and entrepreneur Thomas Boettcher swims, he keeps beside the pool a plastic bag containing pen and paper, to jot down inspirations that strike during his workout. "Swimming enhances my pattern of thinking," he says.

The evidence is even stronger for the long-term benefits of exercise. A study published last September in the Journal of the American Medical Association found that, among more than 18,000 older women studied, those who were most physically active had a 20% lower risk of cognitive impairment. "Long-term regular physical activity, including walking, is associated with significantly better cognitive function and less cognitive decline in older women," the study concluded.

In another study, researchers measured the ability of about 50 senior citizens to distinguish relevant from irrelevant data in a visual exam. The study, published last year in the Proceedings of the National Academy of Sciences, found that aerobic exercise yielded a 20% improvement in performance. "There were substantial effects of exercise on cognition," says Arthur Kramer, a University of Illinois psychology professor and a co-author of that and many similar studies. Dr. Kramer says evidence also suggests that exercise produces acute improvements in short-term memory.

Other research has shown that exercise can make the brain act younger. Dr. Kramer, who directs the Biomedical Imaging Center at the University of Illinois, has had seniors undergo magnetic resonance imaging scans before and after six months of aerobic exercise. The results of the tests suggest that exercise produces patterns of brain activity of the sort typically seen in 20-year-olds, Dr. Kramer says.

Now, researchers are trying to determine just how much and what type of exercise produces the greatest cognitive benefits. "How long do you need to exercise? At what intensity? And how long-lasting are the effects?" asks Jennifer Etnier, a University of North Carolina at Greensboro professor who is researching those questions.

Thus far, it seems likely that extreme amounts -- marathons, for instance -- can hurt as much as help, while modest amounts of activity as simple as walking can be beneficial.