Moderate to vigorous aerobic exercise in the morning may reduce symptoms of attention-deficit/hyperactivity disorder (ADHD) in young children at risk for the illness, new research suggests.
A randomized study of 202 kindergarteners, 1st graders, and 2nd graders showed that those who completed 12 weeks of before-school physical activity had significantly higher reductions in inattention and moodiness than those who completed a sedentary classroom-based intervention.
In addition, the subgroup of children with elevated ADHD symptoms who went through the before-school exercise program showed reduced impairment associated with ADHD risk in both their school and home settings.
"To our knowledge, this is the first large-scale, randomized trial looking at physical activity as a management strategy for ADHD symptoms," lead author Betsy Hoza, PhD, professor of psychological sciences and the Bishop Joyce Chair of Human Development at the University of Vermont in Burlington, told Medscape Medical News.
"We need more studies to replicate the results, but I think the take-home message is that aerobic exercise is a health-producing activity ― and there are really no negative side effects from it," added Dr. Hoza.
The study was published online September 10 in the Journal of Abnormal Child Psychology.
Past research has shown some positive effects from exercise on patients with ADHD, providing evidence that it may be "a viable strategy for improving symptoms, behavior, achievement, inhibitory control, and neurocognitive function in youth with elevated ADHD symptoms," write the investigators.
However, they add that these studies have had several shortcomings, including small sample sizes and often no control group.
In the current study, the researchers enrolled 94 children at risk for ADHD and 108 children deemed "typically developing" to act as their control group.
All participants were randomly assigned to participate for 31 minutes each school day in either a before-school program of moderate to vigorous physical activity (n = 104, 56% boys, 47% at risk for ADHD) or a sedentary classroom-based intervention consisting of art projects (n = 98, 51% boys, 46% at risk for ADHD). Both programs lasted 12 weeks.
The physical activity involved continuous movement requiring children to breathe hard and included a variety of age-appropriate activities and games.
The investigators collected both parent- and teacher-rated reports of ADHD symptoms (including hyperactivity/impulsivity and inattention), symptoms of oppositional behavior and moodiness, and behavior toward and reputation with peers.
These measures included the home and school versions of the ADHD-IV Rating Scale and the Oppositional/Defiant subscale of the Pittsburgh Modified Conners Parent and Teacher Rating Scale.
Wide Range of Improvements
Results showed that all of the children had some improvements no matter which intervention they were assigned to. Parents reported significant decreases in their children's ADHD symptom severity, including hyperactivity/impulsivity and inattention (both, P < .001), as well as oppositional behavior (P < .001) and moodiness (P = .002). There were more decreases in the ADHD-risk group vs the typically developing group.
Plus, they reported that inattention and moodiness severity reductions were significantly greater for the children who participated in the physical activity vs the sedentary activity (P = .01 and .03, respectively).
Teachers also reported overall reductions in hyperactivity/impulsivity and inattention (P < .001), with greater decreases in the ADHD-risk group. "However, these findings did not vary as a function of intervention," write the investigators. And there was no change in severity of oppositional symptoms.
Follow-up analyses showed that parent reports of ADHD and oppositional symptom severity changed significantly for the children at risk for ADHD after completing either of the interventions. Teachers also reported this for the decrease in ADHD symptoms but, again, not in oppositional symptoms.
In the follow-up, parents also reported significant decreases in moodiness only for the ADHD-risk children who completed the physical activity intervention. The only symptom reductions they reported for children in the typically developing group who completed the sedentary intervention was hyperactivity/impulsivity. Teachers reported decreases in both hyperactivity/impulsivity and inattention in this subgroup.
When assessing problematic peer functioning, parent reports showed an overall reduction in both problematic peer behavior (P < .001) and problematic peer reputation (P = .008) during either intervention, again with greater effects found in the ADHD-risk group vs the typically developing group.
Follow-up showed that parents reported only improved peer reputation for the ADHD-risk children who participated in physical activity, and teachers reported significant improvement in peer behaviors in this subgroup.
"Although our findings indicated that all participants showed improvements, children with ADHD risk receiving exercise benefitted across a broader range of outcomes than those receiving the sedentary activities," said coinvestigator Alan Smith, PhD, chair of the Department of Kinesiology at Michigan State University in East Lansing, in a release.
"Despite the number of remaining questions, physical activity appears to be a promising intervention method for ADHD with well-known benefits to health overall," added Dr. Smith.
Dr. Hoza noted that although more research is now needed to better explore what the results mean, exercise is an important activity to promote in general. "It's really a no-lose situation to promote physical activity among America's youth, especially in light of the rising obesity rate," she said.
Asked for comment, John J. Ratey, MD, clinical associate professor of psychiatry at Harvard Medical School, told Medscape Medical News, "This was a good study but didn't show all I would have liked for it to show."
He noted that although the results point out the critical benefits of exercise in promoting better mood and attention, he was disappointed that the findings were not more statistically significant ― especially in reference to the children at risk for ADHD.
Dr. Ratey, who was not involved with this research, has written the book Spark: The Revolutionary New Science of Exercise and the Brain and is Reebok's Ambassador for Active Kids.
He noted that there has been recent research from Taiwan that has looked at using different types of exercise to treat kids with ADHD, as well as a big study from China suggesting that balance training can help youth with the disorder.
"So there's been a lot of good noise going on around it, and there's a whole lot of stuff we know now about what exercise does," said Dr. Ratey.
"I've said for many years that exercise is one of the top three additional treatments for all ADD people, because we've seen that it is so helpful. We're now getting more and more data on that, and I'm more convinced than ever with my patients."
Dr. Ratey added that exercise increases dopamine and norepinephrine levels, which in turn can help decrease symptoms of ADHD. "It also raises serotonin and all these other factors in the brain that really make for a nice recipe for an exercise pill, if we had such a thing," he said.
The study authors and Dr. Ratey have reported no relevant financial relationships.
J Abnorm Child Psychol. Published online September 10, 2014. Abstract
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Cite this: Before-School Exercise May Reduce ADHD Symptoms - Medscape - Sep 18, 2014.