Aerobic exercises are good for the brain

Regular exercise speeds learning and improves blood flow to the brain, says a new study.

While there is ample evidence of the beneficial effects of exercise on cognition (mental condition) in animal models, it has been unclear whether the same holds true for people, said study author Judy L. Cameron, a psychiatry professor at the Pitt School of Medicine.

Testing the hypothesis in monkeys can provide information that is more comparable to human physiology.

”We found that monkeys who exercised regularly at an intensity that would improve fitness in middle-aged people learned to do tests of cognitive function faster and had greater blood volume in the brain’s motor cortex than their sedentary counterparts,” Cameron said.

”This suggests people who exercise are getting similar benefits,” he added.

For the study, the researchers trained adult female cynomolgus monkeys to run on a human-sized treadmill at 80 percent of their individual maximal aerobic capacity for one hour each day, five days a week, for five months.

Another group of monkeys remained sedentary, meaning they sat on the immobile treadmill, for a comparable time.

Half of the runners went through a three-month sedentary period after the exercise period. In all groups, half of the monkeys were middle-aged (10 to 12-year-old) and the others were more mature (15 to 17-year-old).

Initially, the middle-aged monkeys were in better shape than their older counterparts, but with exercise, all the runners became more fit.

During the fifth week of exercise training, standardised cognitive testing was initiated and then performed five days per week until week 24.

In a preliminary task, the monkeys learned that by lifting a cover off a small well in the testing tray, they could have the food reward that lay within it.

In a spatial delay task, a researcher placed a food reward in one of two wells and covered both wells in full view of the monkey. A screen was lowered to block the animal’s view for a second, and then raised again.

If the monkey displaced the correct cover, she got the treat. After reliably succeeding at this task, monkeys that correctly moved the designated one of two different objects placed over side-by-side wells got the food reward that lay within it, said a Pitts release.

”Monkeys that exercised learned to remove the well covers twice as quickly as control animals,” Cameron said. “Also, they were more engaged in the tasks and made more attempts to get the rewards, but they also made more mistakes.”

She noted that later in the testing period, learning rate and performance was similar among the groups, which could mean that practice at the task will eventually overshadow the impact of exercise on cognitive function.

The findings are available in Neuroscience.