Exercise Boosts Kids' Cognitive Performance, Brain Function

Deborah Brauser

October 01, 2014

Moderate to vigorous physical exercise may increase children's cognitive performance and brain function, new research shows.

Dr Charles Hillman

A randomized controlled trial (RCT) of 221 prepubertal children showed that those who participated in a structured afterschool exercise program for 9 months experienced improved executive function, including cognitive flexibility, compared with their counterparts who did not participate in the program.

"In cross-sectional studies, we can't really make causal statements. But with our RTC, we were able to use a causal design and show that this relationship between physical activity and cognition exists," lead author Charles Hillman, PhD, professor of kinesiology and community health at the University of Illinois at Urbana–Champaign, told Medscape Medical News.

"What's truly novel about our study is that through the course of this intervention, we were also able to show changes in brain function and cognition. And the relationship appears to follow a dose-response association as a function of time spent in the program," added Dr. Hillman.

The study was published online September 29 in Pediatrics.

Dose Response

"Physical activity programs have been shown to have positive implications for children's cognitive performance and brain structure and function," the investigators write. However, they note that "additional RCTs are needed to determine whether daily physical activity influences executive control and its neural underpinnings."

In the current study, 221 children between the ages of 7 and 9 years were randomly assigned to participate in the FITKids program for 9 months (n = 109, 51% boys) or to serve as "wait-list controls" (n = 112, 56% boys).

The FITKids intervention occurred for 2 hours every day after school and consisted of a variety of age-appropriate physical activities. All of the participants in this group completed at least 70 minutes of moderate to vigorous physical activity during each session.

Dr. Hillman explained that the intervention was designed to mirror the way children move. "They performed short bouts of exercise interspersed with rest over a 2-hour period."

In addition to changes in fitness, the study outcomes included changes in electrical activity in the brain, as measured by electroencephalography, as well as behavioral measures of executive control.

As expected, results showed that FITKids program participants had significantly greater improvement in aerobic fitness compared with control participants.

"We saw about a 6% increase in fitness in children in the FITKids intervention group," said Dr. Hillman, adding that the wait-list group improved less than 1% during the course of the study.

The intervention group also showed greater improvements in inhibition (3.2%; 95% CI, 0.0 - 6.5) and cognitive flexibility (4.8%; 95% CI, 1.1 - 8.4) compared with the control group.

Results showed that only the intervention group experienced increased attentional resources during tasks requiring increased inhibition (1.4 µV; 95% CI, 0.3 - 2.6) and cognitive flexibility (1.5 µV; 95% CI, 0.6 - 2.5).

Although attendance in the exercise program was positively correlated with change in performance on tasks demanding increased inhibition, working memory, and cognitive flexibility (P = .01), it did not have a significant effect on tasks requiring less executive control.

In addition, attendance results showed that "fitness-related benefits appear to follow a dose-response relationship."

Brain Health Boost

They add that the overall findings are particularly important for educators and policy makers because of the steep decline in exercise options at school.

"Specifically, policies that reduce or replace PA [physical activity] opportunities during the school day (eg, recess), in an attempt to increase academic achievement, may have unintended effect," the authors write.

"The current data not only provide causal evidence for the beneficial effects of PA on cognitive and brain health, but they warrant modification of contemporary educational policies and practices, and indicate that youth should receive more daily PA opportunities."

Dr. Hillman noted that all of this is especially important for children because their brains are still growing.

"These behaviors can shape brain development. That should have implications not just for improved cognitive performance but also for cognition underlying scholastic achievement," he said.

"It's important to point out that we weren't taking low-fit children and over the course of 9 months changing them into high-fit kids. We aren't asking to make all our kids into superstar athletes. Small changes in physical activity that lead to small improvements in fitness appear to have serious, positive implications for brain health."

Novel Finding

"I think this is a valuable study and is another piece of evidence that shows that time spent in physical activity rather than in classroom instruction does not damage children educationally, and may actually be helpful," Catherine L. Davis, PhD, professor of pediatrics and physiology at the Georgia Prevention Center, Medical College of Georgia, in Augusta, told Medscape Medical News.

Dr Catherine Davis

However, she noted some misgivings with the study's methodology and would like to see more information on the randomization procedures and intent-to-treat analysis.

Dr Davis, who was not involved with this research, was lead author of an RTC published in 2011 showing that exercise improved executive function and altered brain activation in overweight children. More recently, she and her colleagues have published studies examining exercise's effects on white matter integrity.

She noted that the current study is consistent with research from other laboratories showing some cognitive benefits from physical activity in children.

"The novel piece about this work for me was the cognitive flexibility results. I don’t believe that's been shown before in a clinical trial," said Dr Davis.

She added that its take-away message is that physical activity is just as necessary as good nutrition for children to grow up healthy.

"There are a lot of good reasons to enroll children in these programs. The key is to find a program that will also support healthy socioemotional development ― and is one that a child will enjoy."

The study authors have reported no relevant financial relationships.

Pediatrics. Published online September 29, 2014. Full article

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