University research links exercise to mind power

By Rob Warren

Exercise helps the mind maintain cognitive ability, preserves brain structure and may also delay the effects of dementia, such as Alzheimer’s disease, University researchers reported in a recent review.

The American Psychological Association presented this review, which was compiled by postdoctoral student Kirk Erickson, Beckman Fellow Stanley Colcombe and professor Arthur Kramer, at their annual convention in New Orleans.

“Older brains, as a natural part of the aging process, experience shrinkage and changes in functioning and structure,” Erickson said. “Exercise seems to have a big effect on these outcomes for older adults.”

One study the researchers reviewed showed not only the growth of new capillaries in the brain structure, but also new neurons.

“It’s not like your eighth grade science teacher said, ‘You can never get brain cells back,’ Erickson said. “Research has shown at least two regions of the brain where neurons grow.”

The review looked at research from dozens of human and animal studies.

The human studies focused more on cognitive test performance, looking at response times and memory capacity. Animal studies focused more on brain chemistry, Erickson said.

“We’re interested in bridging the gap between human and animal studies,” Erickson said. “Pinpointing the mechanisms of exercise’s benefits and finding how it’s working.”

Animal studies have the advantage of being able to dissect a subject’s brain, Erickson said. One chemical animal researchers observe in animals is called brain-derived neurotrophic factor, which is associated with preventing brain damage.

Researchers could compare the amount of the chemical in an exercising animal to that of a non-exercising animal.

Human studies, however, are observational and can focus on statistical studies or long-term experiments.

One of the epidemiological studies collected hundreds of types of data from thousands of older adults, such as socioeconomic status, profession, education and frequency of exercise, Erickson said. Researchers found that increased physical activity decreased the probability of dementia.

Some of the reviewers’ longitudinal human studies at the Beckman Institute were included in the review.

In one study, the team asked elderly subjects to perform aerobic exercises for six months. They were tested before and after, with noticeable improvement performing cognitive tasks.

“Not only was there an improvement in cognitive performance but greater activation within the cortical areas,” said Ruchika Wadhwa, a graduate research assistant for the study.

Kramer’s lab is currently working on a one-year version of the study. The researchers are testing the subjects before the aerobic program, six months later, and afterward hoping to see if performance continues to improve, Erickson said.

“How far can we push the envelope with exercise?,” Erickson said. “How much can performance on cognitive tasks increase?”