A nine-month after-school exercise program helped young kids lose body fat and improve heart and lung strength compared to kids who didn't do the program, according to a new trial.
It's clear that activity is good for kids, lead author Naiman A. Khan told Reuters Health. But he was surprised at just how much of a difference this program made.
"We saw their overall body fat, abdominal fat go down, and in the absence of the program kids actually increased in overall body fat," said Khan, from the University of Illinois at Urbana-Champaign.
For their study, the researchers randomly divided 220 kids ages eight and nine into two groups. One group participated in the FITKids program, which includes 70 minutes of moderate to vigorous physical activity five times per week for nine months, and the other group did not.
In the exercise group, kids did 20 to 25 minutes of health-related fitness activities plus 50 minutes of organized noncompetitive games meant to keep their hearts beating at 55 to 80 percent of their maximum heart rate.
That's higher than most previous exercise studies have aimed for, which may be why this study got such good results, according to Dianne Stanton Ward of the University of North Carolina Gillings School of Global Public Health in Chapel Hill.
Ward studies obesity prevention in children. She was not involved in the new research.
During exercise, kids wore heart rate watches so the researchers could monitor their activity levels.
After nine months, the kids in the exercise group had lost an average of close to one percent of their total body fat and more than one percent of the fat around their belly area, as reported in Pediatrics.
Both kids who were a healthy weight and overweight or obese kids lost fat mass, but overweight or obese kids tended to lose a bit more relative to their starting size.
Kids in the comparison group gained a small amount of fat over the nine-month period, and didn't get any more or less fit.
The researchers "did a lot of things right in this study," including measuring physical fitness as well as body composition, Ward told Reuters Health. The results indicate that staying active at this age influences the development of body fat and produces measurable changes in physical fitness.
"And the kids must have had fun, because they didn't have to do this," she said, noting that few kids skipped days of the program.
"It doesn't really matter