$Preschool math$

The cognitive benefits of exercise for children

© 2008 Gwen Dewar, Ph.D., all rights reserved

Here's intriguing news:

Exercise reshapes the brain and boosts cognitive performance.

Consider this evidence of the benefits of exercise for children.

Lessons from mice: A key study

At the Salk Institute, Henriette van Pragg and her colleagues compared sedentary mice with mice that ran an average of 3 miles each night on a running wheel (van Pragg et al 1999).

Compared with the couch potatoes, the aerobically-challenged mice showed dramatic brain growth.

Specifically, the hippocampus—-a brain region associated with learning and memory--was twice as large.

In addition, the brain cells of the aerobic mouse could sustain longer bouts of “long-term potentiation,” the increased efficiency of communication between neurons that occurs after neurons fire.

Better learning, too

Did these changes translate into better learning? Indeed they did. Mice who exercised performed better on a spatial learning task (finding their way through a water maze).

Why does it work?

Sure, exercise improves mood…and being in a good mood may make it easier for people (and mice) to focus on learning. But it seems pretty clear that much more is going on.

Since the late 1990s, research has revealed that aerobic exercise

• boosts levels of brain-derived neurotrophic factor (BDNF), a substance important for a substance essential for the growth of brain cells

• stimulates neurogenesis—the birth of new neurons

• mobilizes the expression of genes that are believed to enhance brain plasticity—i.e., the ability of the brain to change its neural pathways

and

• prevents brain tissue loss in older adults

(For reviews, see Cotman and Berchtold 2002 and von Pragg 2008).

What about kids?

Admittedly, most of what we know about exercise comes from research on rodents, not humans. Ethical considerations prevent us from running the van Pragg experiments on kids.

But some studies have attempted to directly measure the benefits of exercise for children.

For example, one experiment on overweight kids found that 40 minutes a day of aerobic exercise improved executive function—-that aspect of intelligence that helps us pay attention, plan, and resist distractions (Davis et al 2007).

There is also evidence that exercise for children enhances academic performance.

Consider what happens when primary schools cut back on academic instruction in order to make more time for physical play. We might expect academic performance to suffer. But instead, kids either maintain or improve their academic performance (Trudeau and Shephard 2008).

In addition, there is a positive correlation between physical fitness cognitive performance.

An experiment presented school-aged kids with a stimulus discrimination task—asking kids to quickly distinguish pictures of cats and dogs (Hill et al 2005). As each kid responded, his brain activity was recorded in the form of event-related potentials (ERPs)—the electrical activity that accompanies thoughts and perceptions.

The results?

The brains of physically fit kids showed evidence of more extensive processing during the task. And, compared to sedentary kids, fit kids had faster reaction times.

Exercise for children:

A safe bet...but make it fun

Correlations don’t tell us about causation. It’s possible, for instance, that smarter kids are more likely to seek out physical activity. And that could explain the results of the stimulus discrimination experiment.

But based on the evidence from rodent research, I think that exercise for children is probably beneficial for the brain. Given that physical fitness is also good for the body, it seems we have nothing to lose by encouraging kids to exercise.

But there’s a catch: Exercise should be fun. The mouse experiments are based on voluntary wheel-running. When rodents are forced to exercise, they don’t always reap the benefits.

So it’s important to find form(s) of aerobic exercise that your child really enjoys. Structured activities—-like team sports or dance lessons—-may be fine options. But so are nature walks, tree-climbing, roller-skating, and playing hide-and-seek.

In fact, play--like exercise--is good for the brain. Perhaps the most effective exercise for children is free, unstructured, physical play.

References: Cognitive benefits of exercise for children

Colcombe, S. & Kramer, A.F. 2003. Fitness effects on the cognitive function of older adults: A meta-analytic study. Psychological Science, 14, 125-130.

Cotman, C.W. & Berchtold, N.C. 2002. Exercise: a behavioral intervention to enhance brain health and plasticity. Trends in Neurosciences, 25 (6), 295-301.

Dietrich, A. & Sparling, P.B. 2004. Endurance exercise selectively impairs prefrontal-dependent cognition. Brain and Cognition, 55 (3), 516-524.

Hillman CH, Castelli DM, and Buck SM. 2005. Aerobic fitness and neurocognitive function in healthy preadolescent children. Medicine and science in sports and exercise 37(11): 1967-1974.

Molteni, R., Wu, A., Vaynman, S., Ying, Z., Barnard, R.J. & Gómez-Pinilla, F. 2004. Exercise reverses the harmful effects of consumption of a high-fat diet on synaptic and behavioral plasticity associated to the action of brain-derived neurotrophic factor. Neuroscience, 123 (2), 429-440.

Tomporowski, P.D. 2003. Effects of acute bouts of exercise on cognition. Acta Psychol (Amst), 112, 297-324.

van Praag H, Christie BR, Sejnowski TJ, Gage FH 1999. Running enhances neurogenesis, learning, and long-term potentiation in mice. Proc Natl Acad Sci USA, 96, 13427-31.