This is the second in a three-part series of essays by UC Irvine pediatrician Dr. Dan Cooper on children and exercise. The photos are winners from this summer’s “Children at Play” photo contest, sponsored by UCI’s Pediatric Exercise Research Center, Children’s Hospital of Orange County and The Orange County Register.
Data from scientists, teachers and parents’ real-life experience provide growing evidence that physical activity influences the brain.
In lab animal studies, physical exercise causes new brain cell growth and releases chemicals involved in learning. Recent studies also show that exercise causes the production of substances that protect delicate neurons from free radicals and oxidants that damage living cells.
There also are studies showing how people suffering from chronic disease benefit from physical activity. A number of clinical trials suggest exercise can limit or modestly reduce the progression of Alzheimer’s disease, for example. Other studies show that exercise promotes growth of new “circuits” in brains of stroke victims, thereby restoring lost muscle function. And finally, researchers at the University of Maryland showed that a six-month treadmill program not only improved walking in stroke victims but also activated parts of the brain that control gait. These exciting findings provide new possibilities for therapy in adults suffering from chronic conditions involving the brain.
What about children? Can exercise influence how the brain grows when the rest of the body is developing rapidly? Can it make our kids smarter or, at least, learn better?
Lillian Wald, a pioneering nurse and public health official, championed that idea in the early 20th century when she advocated physical activity in schools. She concluded that healthy, active children learn better. Indeed, the fact that physical education is mandatory (though not always optimally implemented) in public schools in the U.S. and throughout the world, attests to a widespread belief that training the muscles and the brain are intertwined. But, scientific evidence to support Wald’s understanding has been difficult to find, and as school budgets focus on improving academic test scores, some argue that play activities or exercise are a waste of time. School resources are far more likely to be channeled toward basic academics than to physical education, music, or other programs considered marginal to the learning environment.
The challenges to studying the influence of physical activity on learning are enormous, and range from how to measure the time and intensity of the child’s exercise to how to define their academic success. Do we measure grades alone, time spent in studying to achieve a particular grade, or behavior in class? Also, influences such as neighborhood, socioeconomic status, and family play large, confounding roles in improved learning.
Given these hurdles, it is refreshing to see scientists becoming more interested in this tough question. One newly published study from the Centers for Disease Control and Prevention focused on more than 5,000 kindergartners and found that, “physical education did not appear to negatively affect academic achievement in elementary school students.” The researchers went on to note, “… among girls, higher amounts of physical education may be associated with an academic benefit.” A positive effect in boys in the CDC study was equivocal.
In the early 2000s, former California State Superintendent of Public Instruction Delaine Eastin compared standardized testing data obtained routinely from school-age children and adolescents and found:
- Higher academic achievement was associated with higher levels of fitness at each of the three grade levels measured.
- The relationship between academic achievement and fitness was greater in mathematics than in reading, particularly at higher fitness levels.
- Students who met minimum fitness levels in three or more physical fitness areas showed the greatest gains in academic achievement.
- Girls demonstrated higher achievement than boys, particularly at higher fitness levels.
These results were similar to the ones found by the CDC this year.
Finally, there has been renewed interest in using exercise as a learning aid for children with special needs, such as those with attention deficit hyperactivity disorder. Their inability to focus may be the result of sluggish production of adrenaline-like substances. Most of the successful drug therapies for ADHD use medicines that boost adrenaline-like functions in the brain and throughout the body. Adrenaline is released naturally with vigorous exercise, and likely causes the increased attention and awareness most people experience when they exercise. Can this natural property help children with ADHD learn better, reducing their need for medicines? The answer is not yet known.
The brain, like so many other organs, can be profoundly influenced by patterns of physical activity. Healthy children need the right amount of exercise for their optimal growth, development and health. There also is increasing evidence that exercise can, under the right circumstances, help children learn. It clearly does not impair academic performance as judged by standardized testing.
For parents and pediatricians the practical question becomes: At how young an age do patterns of physical activity begin to have long-term physical and mental health effects on the growing child. In next week’s final essay in this series, we will discuss whether we can influence activity levels in babies and, if so, whether the activity level of an infant or baby could change the subsequent development of their motor, cognitive and other critical physiological functions.