What’s the Big Idea?
The idea of “brain training” conjures up visions of children playing educational computer games and senior citizens solving Sudoku puzzles, but a great workout for the brain requires no more equipment than shorts and a T-shirt. People of all ages who get a moderate amount of aerobic exercise have better brain function than sedentary people.
Although parents sometimes worry that allowing children to run around might take time away from schoolwork, exercise does not hurt academic performance. Instead, research shows that fit children are smarter than couch potatoes. An analysis of multiple studies found that children (ages four to eighteen) who are physically active score higher on IQ tests, verbal ability, math ability, perceptual skills, and academic readiness.
Children who exercise have better self-control than children who don’t exercise. In one study, fit nine- and ten-year-olds (those in the top 30 percent on fitness) showed substantially stronger cognitive control in a demanding attention task than children whose fitness level was in the lowest 30 percent. Fit children also have greater volume in the dorsal striatum, a brain region involved in cognitive control and the resolution of conflicts among competing potential responses.
Correlational studies leave open the possibility that the children who became fit might have had better self-control in the beginning, so scientists give more weight to intervention studies, which support a causal relationship between exercise and self-control. For example, overweight sedentary children, ages seven to eleven, had improved self-control after being randomly assigned to three months of aerobic exercise for twenty or forty minutes per day, in a program that emphasized enjoyment rather than competition. Mathematics achievement was also higher in the forty-minute group. Functional magnetic resonance imaging showed more prefrontal cortex activation in both exercise groups than in children who don’t exercise.
There’s one caveat to the recommendation that exercise is good for children’s brains—the risk of head injury from contact sports. Children take longer than adults to recover from a concussion, and those who are injured again during recovery can develop serious complications. Athletes under age eighteen account for more than 90 percent of deaths due to sports-related head injury in the U.S. since 1945. Head injury also increases the risk of a neurodegenerative disease called chronic traumatic encephalopathy, which causes depression, memory loss, and problems with impulse control.
Martial arts that emphasize mindfulness may be a particularly effective form of exercise for promoting self-control. An intervention study showed that traditional tae-kwon-do training improves self-control in middle-class elementary school students, with an especially large effect in boys, perhaps because it combines physical activity with learning an increasingly difficult skill. In another intervention study, mindfulness training alone improved self-control in second and third graders. The program took thirty minutes twice a week for eight weeks and included exercises to promote awareness of the self, other people, and the surrounding environment.
What’s the Significance?
The brain benefits of exercise last a lifetime. Even people who start exercising in their 60s or 70s show improvements in self-control. Exercise also reduces the risk of dementia later in life. Regular exercise from middle age reduces the risk of developing Alzheimer’s disease in the 70s by a factor of three. Starting to exercise as late as the 60s can still reduce the risk by half.
In long-term studies, children who don’t exercise often turn into adults who don’t exercise. That’s why parents should take advantage of young children’s urges to run around to introduce them to organized sports and hobbies that may continue into adulthood, such as martial arts, dance, softball, or hiking. By encouraging their children to move their bodies regularly, parents can lay the groundwork for better brain function in adulthood—and save the money they could have spent on brain training games for college.
Big Think interviews Sandra Aamodt: