Edited by Kate Findley, The Great Courses Daily
As it turns out, when you go for your daily jog or weightlifting session, you’re not just getting your body in shape—you’re also enhancing your brain health. Dr. Richard Restak explains how exercise benefits the young and old alike, preventing dementia and enhancing executive function.
How Exercise Enhances Brain Health
Scientists now recognize that exercise plays an integral role in brain health. This wasn’t always the case, though.
“I’m, for instance, a member of a generation that made firm distinctions between the mental and the physical,” Dr. Restak said. “As a student you were either a good student or an athlete. It’s very rare that the two of them were combined.”
Now that has changed thanks to people like Bill Bradley, former U.S. Senator and professional basketball player; and Sebastian Coe, the British politician and runner who won four Olympic gold medals. The brain does not operate in isolation to other organs but has similar needs such as glucose, oxygen, and other nutrients.
The benefits of exercise include increased blood flow and new capillaries around neurons, increased production of new neurons, more interconnections between neurons, the protection of dopamine neurons from neurotoxins in the environment, and elevations in nerve growth factor.
Walking Leads to Dementia Reduction
Additionally, exercise enhances prefrontal executive processes, which are necessary for helping us to stay on task. In fact, a daily one-mile walk reduces dementia risk by 50 percent.
Older adults with a history of exercise have better-preserved brains than those of the same age who have not exercised, according to Arthur Kramer, Professor of Psychology and Director of the Center for Cognitive and Brain Health at Northeastern University. The frontal, parietal, and occipital lobes are most influenced.
The frontal and prefrontal lobes focus our attention on what we’re thinking about, and the parietal and temporal lobes concentrate on what we’re doing; this combination results in enhanced memory and focus.
According to Kramer, “The largest gains involve the executive processes…These are the processes that show substantial age-related decline.”
A short time frame is sufficient to establish improvement. Just six months of regular exercise increases brain volume. Three walks of 45 minutes per week is enough to reduce the likelihood of dementia by 50 percent.
A study published in Neurology by Kirk Erickson of the University of Pittsburgh revealed positive changes in the chemical messenger system along with an antidepressant effect. His group reported that walking six to nine miles a week may preserve brain size and consequently stop memory deteriorating in later life.
Fitness, Children, and Neurocognition
Nor are the effects of exercise on the brain confined to adults. Two separate studies of nine- and 10-year-olds at the Champaign-Urbana campus of the University of Illinois showed that exercise can alter brain structure and improve cognitive abilities.
MRIs showed that fitter children scored better on tests of attention. They had significantly larger basal ganglia, which is a key part of the brain that aids in maintaining attention, and the executive control needed to coordinate actions and plans.
In the second study, this time of complex memory, the hippocampus was found to be larger in the fitter children. In summary, researchers suggest that being fit may enhance neurocognition in young people by increasing the size of the hippocampus and basal ganglia and strengthening the connection between them.
Making Exercise Enjoyable
Think of exercise on a continuum model. At one end, exercise is no longer necessary for survival. We don’t have any lions we need to escape from. On the other end are the zealots; these people script their whole lives around compulsive exercise.
Research also points to some evidence of a genetic predisposition for exercise. Twin studies, based on pairs of identical twins who were separated at birth and then studied separately years later, show that identical pairs are more likely to share exercise patterns.
There are several variations and genes related in our response to fatigue, judgments about exercise as being mentally rewarding or not being mentally rewarding, as well as how efficiently the body regulates energy. The study implies that some people may be more drawn to exercise than others, but the choice to exercise is still ours to make for the sake of our brain health.
“My personal response to the genetic studies is, well, now I don’t feel so guilty since I rarely feel the urge to exercise, nor do I particularly enjoy it,” Dr. Restak said. “But I also recognize that if I had followed a path of only doing what I ‘felt like’ doing, I would never have written 20 books about the brain.
“So even if I’m genetically inclined not to exercise, I can and will overcome that limitation. … My personal exercise program consists of about a 35- to 45-minute brisk walk through different parts of Washington, D.C.”
You must decide for yourself, then, whether you want to engage in moderate or strenuous exercise. If you’re over age 50 and not in good physical shape, you should have a stress test and a physical before beginning any type of exercise program.
Also, decide what benefits are most important to you. Are you after weight loss, improved health, or enhanced cognition?
Look for ways to make fitness fun. Get together with friends and take long walks. You can try different walking routes and thus combine exercise with learning about your city or town.