Twenty minutes of exercise may help kids with attention-deficit hyperactivity disorder (ADHD) settle in to read or solve a math problem, new research suggests.
The small study, of 40 eight- to 10-year-olds, looked only at the short-term effects of a single bout of exercise. And researchers caution that they are not saying exercise is the answer to ADHD.
But it seems that exercise may at least do no harm to kids' ability to focus, they say. And further studies should look into whether it's a good option for managing some children's ADHD.
"This is only a first study," said lead researcher Matthew B. Pontifex, of Michigan State University in East Lansing.
"We need to learn how long the effects last, and how exercise might combine with or compare to traditional ADHD treatments" like stimulant medications, Pontifex explained.
He noted that there's been a lot of research into the relationship between habitual exercise and adults' thinking and memory, particularly older adults'. But little is known about kids, even though some parents, teachers and doctors have advocated exercise for helping children with ADHD.
So for their study, Pontifex and his colleagues recruited 20 children with diagnosed or suspected ADHD, and 20 ADHD-free kids of the same age and family-income level.
All of the children took a standard test of their ability to ignore distractions and stay focused on a simple task at hand - the main "aspect of cognition" that troubles kids with ADHD, Pontifex noted. The kids also took standard tests of reading, spelling and math skills.
Each child took the tests after either 20 minutes of treadmill exercise or 20 minutes of quiet reading (on separate days).
Overall, the study found, both groups of children performed better after exercise than after reading.
On the test of focusing ability, the ADHD group was correct on about 80 percent of responses after reading, versus about 84 percent after exercise. Kids without ADHD performed better - reaching about a 90 percent correct rate after exercise.
Similarly, both groups of kids scored higher on their reading and math tests after exercise, versus post-reading.
It's hard to say what those higher one-time scores could mean in real life, according to Pontifex, who published his results in The Journal of Pediatrics.
One of the big questions is whether regular exercise would have lasting effects on kids' ability to focus or their school performance, he said.
And why would exercise help children, with or without ADHD, focus? "We really don't know the mechanisms right now," Pontifex said.
But there is a theory that the attention problems of ADHD are related to an "underarousal" of the central nervous system. It's possible that a bout of exercise helps kids zero in on a specific task, at least in the short term.
Parents and experts alike are becoming more and more interested in alternatives to drugs for ADHD, Pontifex noted. It's estimated that 44 percent of U.S. children with the disorder are not on any medication for it.
And even when kids are using medication, additional treatments may help them cut down their doses. Pontifex said future studies should look at whether exercise fits that bill.
"We're not suggesting that exercise is a replacement, or that parents should pull their kids off of their medication," Pontifex said.
But, he added, they could encourage their child to be active for the overall health benefits, and talk with their doctor about whether exercise could help manage ADHD specifically.
"Exercise is beneficial for all children," Pontifex noted. "We're providing some evidence that there's an additional benefit on cognition."