Physical Activity Falls Sharply During Adolescence

Though 9-year-olds get plenty of activity, by age 15 youths get less than the daily hour needed

TUESDAY, July 15 (HealthDay News) -- Between the ages of 9 and 15, physical activity fell steeply for American boys and girls in a geographically diverse sample, according to research published in the July 16 issue of the Journal of the American Medical Association.

Philip R. Nader, M.D., of the University of California San Diego in La Jolla, Calif., and colleagues analyzed data from 1,032 youths whose moderate-to-vigorous physical activity (MVPA) was measured at ages 9, 11, 12 and 15. Participants wore accelerometers for four to seven days to record data for measurement.

At age 9, children participated in MVPA roughly three hours daily on weekdays and weekends -- well above the expert-recommended 60 minutes, the researchers report. However, weekday and weekend activity fell by 38 and 41 minutes per year, respectively. By age 15, participants only engaged in MVPA 49 minutes on weekdays and 35 minutes on weekend days, the investigators found. While boys were found to be more active than girls, boys and girls showed the same rate of decrease, the report indicates.

"The data in our cohort confirm a significant decrease of activity from ages 9 to 15 years in the United States. This decrease augurs poorly for levels of physical activity in U.S. adults and potentially for health over the course of a lifetime. Consequently, there is a need for program and policy action as early as possible at the family, community, school, health care, and governmental levels to address the problem of decreasing physical activity with increasing age," the authors conclude.

Full Text (subscription or payment may be required)

Physician's Briefing