Meeting the 2008 Physical Activity Guidelines for Americans among U.S. youth

Background: Participation in physical activity brings health benefits for adolescents. However, limited data are available on the percentage of U.S. adolescents who engage in levels of aerobic and muscle-strengthening activities recommended in the 2008 Physical Activity Guidelines for Americans (2008 Guidelines). Purpose: To examine the prevalence at which U.S. adolescents aged 12-17 years meet the 2008 Guidelines, and whether demographic and BMI variables influence that prevalence. Methods: Using data from an interviewer-administered self-report questionnaire in the 1999-2006 National Health and Nutrition Examination Survey (analyzed in 2011), estimates were made of the percentage of adolescents who engaged in recommended levels of aerobic and muscle-strengthening activities (≥60 minutes of aerobic activity/day and participation in muscle-strengthening activities ≥3 days/week). Results: Among 6547 U.S. adolescents aged 12-17 years, 16.3% (95% CI=14.9%, 17.9%) met both aerobic and muscle-strengthening guidelines; 14.7% (13.3%, 16.2%) met the aerobic guideline only, 21.3% (19.4%, 23.3%) met the muscle-strengthening guideline only, and 47.8% (45.4%, 50.1%) met neither guideline. Adjusted for covariates, odds of meeting either the aerobic or muscle-strengthening guideline only or both guidelines versus meeting neither guideline were (p<0.05) higher among boys than girls. The odds of meeting the aerobic guideline only were higher among underweight/normal-weight adolescents than among obese adolescents. No clear pattern was observed by family groups according to poverty-to-income ratio. Conclusions: Less than 20% of adolescents reported engaging in recommended levels of both aerobic and muscle-strengthening activities.