Many studies have shown that exercise improves memory and learning in both mice and humans. Now we know more about how and why that is.

Exercise causes high-frequency brain waves called ripples. These waves, researchers found using electrodes implanted in the brains of mice, start in the hippocampus, the region of the brain responsible for memory and learning, then spread to the cortical regions of the brain.

Studies that looked at changes in the flow of oxygenated blood in the human brain seemed to support the idea that exercise also causes ripples starting in the human hippocampus.

“By directly recording brain activity, our study shows that even a single bout of exercise can rapidly alter the neural rhythms and brain networks involved in memory and cognitive function.”

The findings of a recent study led by researchers at the University of Iowa add more evidence for this theory.

The study used intracranial electroencephalography (iEEG) to record electrical activity in the brains of patients with epilepsy who were undergoing a presurgical evaluation. The recordings showed ripples starting in the hippocampus following exercise.

“By directly recording brain activity, our study shows that even a single bout of exercise can rapidly alter the neural rhythms and brain networks involved in memory and cognitive function,” Michelle Voss, corresponding author on the study, said in a statement.

The 14 patients with epilepsy enrolled in the University of Iowa study were between 17 and 50 years old. After a short warmup period, each participant rode a stationary bike at a pace they could maintain for 20 minutes. The researchers recorded their brain activity before and after the cycling session.

The findings should be applicable to people without epilepsy, Voss explained, because the patterns the team observed were similar to the patterns seen in the brains of healthy adults using noninvasive methods such as functional MRI.

“That similarity across very different methods is a strong indicator that these effects are not specific to epilepsy, but reflect a general human brain response to exercise,” said Voss, a professor and Ronnie Ketchel Faculty Fellow in psychological and brain sciences at Iowa.

The effects seen were immediate, so even those who don't get moving until later in life will reap the brain benefits of exercise.

The World Health Organization recommends 150 minutes of moderate intensity exercise a week for adults between the ages of 18 and 64. Even those who don't get moving until later in life can still benefit.

What you eat makes a difference in brain health, too. A diet rich in flavonols can improve the function of the hippocampus. Drinking caffeinated coffee and tea has also been found to slow cognitive decline.

The study is published in Brain Communications.