Dr. Judy Cameron of the University of Pittsburgh School of Medicine found monkeys trained to use a treadmill -- an hour a day five days a week for five months -- performed a mental task twice as quickly as the control group that spent the hour sitting on an immobile treadmill.
The study, published in Neuroscience, found the exercising monkeys more engaged in the task and more willing to make mistakes. Later in the testing, the two groups had similar performances and Cameron suggested practice may eventually overshadow the impact of exercise on cognitive function.
Cameron noted fitness levels of exercising older monkeys quickly caught up to those of exercising middle-aged monkeys. Samples from the brain's motor cortex indicated exercising mature monkeys had greater vascular volume than both middle-aged exercisers and sedentary monkeys, the study said.
However, improved blood flow reversed in the half of the exercisers who became sedentary, Cameron said.
"These findings indicate that aerobic exercise at the recommended levels can have meaningful, beneficial effects on the brain," Cameron said in a statement. "It supports the notion that working out is good for people in many, many ways."