Lifestyle Matters: Exercise

Even single bouts of exercise benefit.

Posted Dec 29, 2020

 Clique Images/Unsplash
Source: Clique Images/Unsplash

Be healthy. Be smart.

Exercise is not only good for the body; it is good for the brain. The idea that exercise might benefit memory originally came from animal research revealing exercise increases learning and memory capability, presumably because exercise stimulates the birth of new nerve cells in the hippocampus, the part of the brain that is crucial for forming long-term memory. I have posted many articles on the benefits of exercise for the brain at http://thankyoubrain.blogspot.com (type “exercise” into the search field).

It is now clear that exercise benefits memory capability in humans too, both old and young. In addition, the state of exercise is tied to memory; that is, state-dependent memory can be demonstrated with exercise. For example, in a study of humans exercising on a bicycle, word lists learned during the exercise were recalled best during another exercise episode, while words learned not riding on a bike were recalled best under that same condition. State-dependent learning has been demonstrated in other contexts too, such as with alcohol and with school-room environments.

Even when I was a kid, which was long before the whole notion of aerobic exercise, people said that being physically active could help you perform better in school. But this was mostly anecdotal, with very little research evidence. Now there is much solid evidence. Sadly, it may have come too late. Many schools have done away with or minimize physical education. Many girls think it’s not cool to sweat.

Charles Hillman and colleagues at the University of Illinois recently reported a study on the effects of exercise on cognitive function of 20 children aged 9 to 10. They administered some stimulus discrimination tests and academic tests for reading, spelling, and math. On one day, students were tested following a 20-minute resting period; on another day, students walked on a treadmill before testing. The exercise consisted of 20 minutes of treadmill exercise at 60% of estimated maximum heart rate. Mental function was then tested once the heart rate returned to within 10% of pre-exercise levels. Results indicated improved performance on the tests following aerobic exercise relative to the resting session. Tests of brain responses to stimuli suggested the difference was attributable to improved attentiveness after just this one bout of exercise.

Note this is just from a single aerobic exercise experience. How can that be beneficial? The most obvious explanation is that exercise generates more blood supply to the brain, but I don't know that this has been documented. Actually, what is known is that exercise diverts blood to the muscles. The generally accepted view is that the body tightly regulates blood flow to the brain and that the brain always gets what it needs.

A more likely explanation is that single bouts of exercise relieve anxiety and stress, which are known to disrupt attentiveness and learning. Maybe the repetitive discipline of exercises like treadmill-walking help entrain the brain into a more attentive mode, akin perhaps to meditation. We need a study that compares treadmill walking with a different kind of exercise regimen (like a vigorous and competitive basketball game, for example).

As for what goes on in a typical school recess, I doubt that such activities as gossiping, text messaging, or whatever else goes on these days with kids at recess markedly interfere with learning.

There is also the possibility a continuing aerobic exercise program could produce long-lasting beneficial effects in young children. My own prejudice is that schools and parents ought to get serious about requiring aerobic exercise programs. It should not only improve the quality of school work but also help combat the epidemic of obesity and diabetes. One caveat: excessive running to achieve aerobic levels of exercise may not be advisable in children. My own experience with jogging, for example, might have been great for my heart and brain, but I now have two artificial knees and an artificial hip joint to show for it.

Here is another caveat you may have thought about: If exercise is so good for academic performance, why do varsity athletes generally make poorer grades than their classmates? Well, there are many other factors, of course. One prevailing attitude among athletes is that academics are less important to them than their sport. Athletes tend to devote their time and energy to their sport, not school work. They also have more incentive to focus on their sport. Students idolize athletic stars. But students who make all As are not considered heroes; they are often considered nerds or otherwise abnormal. What should be normal is to exercise both body and brain.

References

Hillman, C. H., Pontifex, M. B., Raine, L. B., Castelli,, D. M., Hall, E. E., and Kramer, A.F. (2009). The effect of acute treadmill walking on cognitive control and academic achievement preadolescent children, Neuroscience, 159 (3), 1044-1054, https://doi.org/10.1016/j.neuroscience.2009.01.057.

Miles, Christopher, and Hardman, Elinoir. (2010). State-dependent memory produced by aerobic exercise. Ergonomics. 41(1), doi.org/10.1080/001401398187297