Twenty minutes of daily, vigorous physical activity over as few as three months can reduce a childs risk of diabetes and dangerous abdominal fat, according to a study.
Not surprisingly, 40 minutes of daily exercise was even more effective, the researchers found.
Pediatric and adult studies have shown the metabolic benefits of aerobic activity but had yet to dissect the amount of activity needed to elicit a given benefit, the researchers noted.
For the latest study, researchers with Georgia Health Sciences University examined 222 overweight, previously inactive 7- to 11-year-olds in the Augusta, Ga., area. A third of the study participants maintained their typically sedentary lifestyle, a third began a 20-minute heart-rate raising exercise routine after school for three months, and a third exercised for 40 minutes after school.
Children who exercised for 40 minutes had a 22% reduction in insulin resistance compared with the control group, while the 20-minute group had an 18% reduction. The extra 20 minutes also helped the children lose more total body fat and visceral fat, while fitness, which appeared driven by intensity rather than duration, gained a similar boost from both time periods. Benefits were gained without restrictive diets and worked equally well regardless of race.
Catherine Davis, PhD, the studys lead author and a clinical health psychologist at the Institute of Public and Preventive Health at GHSU, said she hopes evidence of the health benefits of a fun, vigorous and relatively short exercise routine will be used to design public health interventions for a society in which a third of elementary school children are overweight.
“Its practical in the sense that we were able to quantify the dose required to make these changes,” Davis said in a news release. “If you are able to get kids active for 20 minutes every day in school, whether through physical education or taking a running break during lunch, that can make a real difference.” She noted that a 40-minute exercise routine may require after-school programs rather than school-time sessions.
“You can reach a lot of kids by making changes at school,” Davis said. “We dont want this to just be for athletic or coordinated kids but for all kids, especially the ones who are less likely to be on a sports team.”
The study appears in the Sept. 19 issue of JAMA. The study abstract is available at http://jama.jamanetwork.com/article.aspx?articleid=1360862.