Before you take away their TV, take them to the park.

RODALE NEWS, EMMAUS, PA—A child’s screen time is a legitimate parental concern. But according to a study just published in the American Journal of Clinical Nutrition, it may not be the best target for fighting obesity in childhood. In the study, the time kids spent getting vigorous exercise was more indicative of their weight than the time they spent planted in front of a screen.

THE DETAILS: Researchers at the Medical Research Council Epidemiology Unit in Cambridge, England, used data from the SPEEDY (Sport, Physical Activity and Eating Behavior, Environmental Determinants in Young people) study to investigate factors that contribute to obesity in childhood. They looked at 1,892 9- to 10-year-old British children, all of whom wore devices on their hips for 12 weeks to assess how physically active they were, and whether their activity was light-intensity, moderate-intensity, vigorous-intensity, or moderate-plus-vigorous intensity. The children’s waist circumference, body mass index, and body fat index was also measured, and the children themselves reported the time they spent in front of TV, computer, and video screens.

The researchers found that the children who spent the most time being sedentary weighed the most. But the time children spent being vigorously physical active was actually more indicative of their weight than the time they spent sedentary. “Overall sedentary time is a risk factor [for overweight], whereas total active time is a ‘health’ factor,” explains Ulf Ekelund, PhD, professor and program leader at the Medical Research Council Epidemiology Unit in Cambridge, England, and author of the study. “But according to our study, the association between vigorous-intensity activities and adiposity was stronger than that between sedentary time and adiposity.”