By GRETCHEN REYNOLDS NYTIMES JUNE 16, 2017
Better grades might be found on the playground. A new study of elementary-age children shows that those who were not part of an after-school exercise program tended to pack on a particular type of body fat that can have deleterious impacts on brain health and thinking. But prevention and treatment could be as simple as playing more games of tag.
Most children do not meet the federal health guidelines for exercise, which call for at least an hour of it a day for anyone under the age of 18. Physical inactivity can result in weight gain, especially around the midsection — including visceral fat, a type of tissue deep inside the abdomen that is known to increase inflammation throughout the body. It is also linked to heightened risks for diabetes and cardiovascular complications, even in children, and may contribute to declining brain function: Obese adults often perform worse than people of normal weight on tests of thinking skills.
But little has been known about visceral fat and brain health in children. For a soon-to-be-published study, researchers from Northeastern University in Boston and the University of Illinois at Urbana-Champaign tracked hundreds of 8-to-10-year-old children in a nine-month after-school exercise program in Urbana. Every day, one group of children played tag and other active games for about 70 minutes. The subjects in a control group continued with their normal lives, with the promise that they could join the program the following year. All the children completed tests of fitness, body composition and cognitive skills at the start and end of the program. The researchers did not ask the children to change their diets.
After the trial, the exercising children who were obese at the study’s onset had less visceral fat relative to their starting weight, even if they remained overweight. They also showed significant improvements in their scores on a computerized test that measures how well children pay attention, process information and avoid being impulsive. Notably, a similar effect was observed in children whose weight was normal at the start. Across the board, the more visceral fat a child shed during the nine months of play, the better he or she performed on the test.
The children in the control group, in contrast, had generally added to their visceral fat; this was particularly true among those who were already obese. They gained, on average, four times as much visceral fat as the normal-weight children in the control group, and also did not perform as well on the subsequent test.
Lauren Raine, a postdoctoral researcher at Northeastern University who conducted the study with Charles Hillman and others, says that the trial was designed to study aerobic fitness and children’s ability to think, not the relation of abdominal flab to inflammation. But a reduction in overall inflammation very likely plays a role, because it is thought to be unhealthy for the brain. More broadly, Raine says, the study suggests that getting children to run around won’t just enhance their bodies — it might also improve their report cards.