Background: Few longitudinal studies have examined seasonal variation in meeting physical activity (PA) recommendations in association with incident overweight among adolescents.
Methods: We assessed self-reported, season-specific PA among 12,949 adolescents in two US cohorts (Growing Up Today Studies 1 and 2). We examined the relationship between the number of seasons per year that adolescents met the recommended amount of moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA), respectively, and the development of incident overweight at the next survey period. The sex-specific analyses controlled for follow-up time, survey month, age, race/ethnicity, sexual maturation, television viewing, region of the country, and intakes of sugar-sweetened beverages and fried foods away from home.
Results: About one-third (34%) of adolescents met the MVPA recommendation of 60 minutes/day, and one-quarter (24%) the VPA recommendation of 3 hours/week, for four seasons of the baseline year. The risk of becoming overweight was 23% (95% confidence interval [CI]: 5%-45%) higher for girls who met the MVPA recommendation for 2 (vs. 4) seasons/year. The risk was similar for girls who met the recommendation for 1 (vs. 4) season/year (odds ratio = 1.23, 95% CI: 1.05-1.44). The number of seasons each year boys met the MVPA recommendation, or girls or boys met the VPA recommendation, was not associated with an increased risk of incident overweight.
Conclusions: Meeting the MVPA recommendation for 1 or 2 (vs. 4) seasons/year is related to higher risk of becoming overweight among adolescent girls but not boys. Interventions to increase PA levels each season may contribute to overweight prevention efforts among girls.
Keywords: exercise; health behavior; pediatrics; physical activity; weight status.