20 or 40 Minutes of Activity May Help Kids Improve Metabolic Markers
Twenty minutes of daily aerobic exercise is good, 40 minutes is even better, to help overweight children lose weight and reduce a handful of risk factors shared among both diabetes and cancer, finds a study published last month in the Journal of the American Medical Association.
For the study, researchers wanted to find out how different amounts of exercise affected several metabolic risk factors, including abdominal (visceral) fat, body fat, and insulin resistance.
The study was conducted among 222 sedentary children; most were obese and a quarter had prediabetes. The 7- to 11-year olds were randomly divided into one of three groups: One group was aerobically active 40 minutes every day after school; a second group for 20 minutes after school, and the third group continued their non-active lifestyle, acting as the control group. The activities were all designed to keep the heart rate up, including running games, jumping rope and playing soccer.
After 13 weeks, the children who were active 40 minutes a day showed the greatest reductions in insulin resistance, body fat, and visceral fat compared to the control group. Those who exercised 20 minutes a day also showed marked improvement in each category compared to the control. Both the 20-minute and 40-minute exercisers showed similar benefits in fitness.
Source: Catherine L. Davis, et al. “Exercise Dose and Diabetes Risk in Overweight and Obese ChildrenA Randomized Controlled Trial.” JAMA. 2012; 308(11):1103-1112. doi:10.1001/2012.jama.10762.