Overweight Kids Who Exercise Improve Thinking, Math
FRIDAY, Feb. 11 (HealthDay News) -- When overweight, sedentary
kids start to exercise regularly, their ability to think, to plan
and even to do math improves, a new study suggests.
In addition, exercise was linked to increased activity in the
parts of the brain associated with complex thinking and
self-control, according to brain imaging scans analyzed by the
"This implies that chronic sedentary behavior is compromising children's ability and achievement," said lead researcher Catherine Davis, a clinical health psychologist at the Georgia Prevention Institute at Georgia Health Sciences University in Augusta.
"We know that exercise is good for you, but we didn't have very good evidence [before this] that it would help children do better in school," said Davis.
Although this study was done among overweight children, she
believes that similar results would be seen in normal-weight
Davis speculates that these positive changes are a result of a
combination of biological and environmental factors. "There are
some neural growth factors that have been identified in mice that
exercise," she said. These benefits may include more brain cells
and more connections between them.
But there are also social and environmental factors, she noted.
"[There's] more stimulation when things are moving faster and when
you're moving. So it is cognitively stimulating to move," Davis
With one-third of U.S. children overweight, Davis thinks that
exercise needs to become an essential part of children's lives.
"Make sure your child has a balanced life -- not only that they study, but that they learn to take care of their bodies as well," she said.
The report is published in the January issue of
For the study, Davis's team randomly assigned 171 overweight
children 7 to 11 years old, to either 20 minutes or 40 minutes of
vigorous exercise every day after school or to no exercise. The
exercise program focused on fun and safety rather than competition
and skill, and included running games, hula hoops and jump ropes.
Researchers found it raised their heart rates to 79 percent of
maximum, which is considered vigorous.
The researchers evaluated the children using standard
achievement tests known as the Cognitive Assessment System and
Woodcock-Johnson Tests of Achievement III. Some children also had
magnetic resonance imaging (MRI) scans of their brains.
The MRIs found that children who exercised had increased
activity in the so-called executive function area of the brain --
associated with self-control, planning, reasoning and abstract
thought -- as well as the prefrontal cortex. The latter is the part
of the brain linked with complex thinking and correct social
behavior, the researchers noted.
There was also decreased activity in an area of the brain that's
behind the prefrontal cortex. The shift seems to be tied to faster
developing of cognitive skills, Davis said.
In addition, the more the kids exercised, the more the
intelligence-test scores went up. An average increase of 3.8 points
on scores in cognitive planning skills was noted in kids who
exercised 40 minutes a day for three months, the researchers
Children who exercised 20 minutes a day experienced smaller
There were also improvements in math skills, but not reading
ability. "The finding of improved math achievement is remarkable,
given that no academic instruction was provided, and suggests that
a longer intervention period may result in more benefit," the
Commenting on the study, Samantha Heller, a dietitian,
nutritionist and exercise physiologist, said: "Take a bunch of
kids, put them outside, give them some balls, jump ropes and street
chalk, and they will be running, jumping and playing hopscotch in
They become happier, more energetic, smarter kids, she said.
"Children's bodies know intuitively that exercise is essential for healthy brain and body function. But when we deny children their natural instincts and allow them to stultify in front of a TV or computer, they become lethargic [and] moody," Heller said, adding that sedentary kids are also prone to being overweight and may do poorly in school.
"It seems a no-brainer to me that for kids' brains to be healthy, they should be encouraged to participate in regular exercise and given the time and place for it," Heller concluded. "We need to turn off the computers, TVs, cell phones and iPads and let kids do what they do naturally: Run around and play."
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