Purpose: This study aimed to examine the effects of substituting sedentary time with sleep or physical activity on adiposity in a longitudinal sample of adolescents.
Methods: Adolescents (10-16 yr) were recruited for a prospective observational cohort. Parents and adolescents reported demographic characteristics and pubertal development. Accelerometry was used to measure sleep, physical activity, and sedentary time. Adiposity was quantified with imaging techniques. Isotemporal substitution modeling was conducted to examine the effect of substituting 10 min of sedentary time with sleep or differing intensities of physical activity. Results were stratified by sex and race and adjusted for covariates.
Results: A total of 217 adolescents provided complete measures at both baseline and 2 yr later (58.1% White, 51.8% girls; 12.9 ± 1.9 yr at baseline). Sleep was negatively related to adiposity 2 yr later when considering other movement behaviors, but substituting baseline sedentary time with sleep was not related to future adiposity ( P > 0.05). In boys and non-White adolescents, substituting sedentary time with vigorous-intensity physical activity was related to lower adiposity 2 yr later ( P < 0.05). Substituting sedentary time for moderate- to vigorous-intensity physical activity was not associated with future adiposity.
Conclusions: Substituting sedentary time with vigorous-intensity physical activity was related to lower adiposity in later adolescence in certain groups. Opportunities to promote an adequate balance of sleep, sedentary time, and physical activity in all adolescents are encouraged for optimal development.
Trial registration: ClinicalTrials.gov NCT02784509.
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