Insufficient physical activity and excessive television viewing among US high school students, 1999-2005

Purpose: To examine secular trends in physical activity (PA) and television (TV) viewing among high school students in the United States. Significance: Overweight among adolescents has increased dramatically in recent years. A physically active lifestyle is an essential element of efforts to promote healthy weight among youth. Procedures: As part of the Youth Risk Behavior Surveillance System, 4 national school-based surveys were conducted between 1999 and 2005. Each survey employed a three-stage cross-sectional sample of students in grades 9-12. Black and Hispanic students were oversampled. Each survey provided self-report data from approximately 14,000 students. Secular trends in insufficient PA (i.e., failure to meet national health objectives for both vigorous PA [20 minutes, ≥ 3 days/week] and moderate PA [30 minutes, ≥ 5 days/week]) and excessive TV viewing (i.e., >2 hours/day) were analyzed using logistic regression models that controlled for sex, race/ethnicity, and grade in school. Findings: From 1999-2005, the overall prevalence of insufficient PA among female (37.6% to 38.5%) and male (23.6% to 23.9%) students did not change significantly. However, among Hispanic females, the prevalence of insufficient PA decreased significantly (45.8% to 37.4%). The prevalence of excessive TV viewing decreased significantly among black females (74.4% to 64.5%) and Hispanic females (51.6% to 45.8%), and among black males (73.0% to 63.5%), Hispanic males (52.7% to 45.8%), and white males (37.2% to 30.2%). Conclusion: These findings suggest increasing participation in moderate to vigorous PA among Hispanic females and decreased TV viewing among female and male adolescents.