ABSTRACT
STUDY OBJECTIVES: Population-based studies on the association of objectively assessed physical activity (PA) with sleep among adolescents are rare. We examined this association by applying accelerometry and accounting for the day-by-day variability. METHODS: Accelerometers (Actigraph GT3X) were worn for one week by 1223 participants during the 15-year follow-up of the German birth cohorts (German infant study on the Influence of Nutrition Intervention plus air pollution and genetics on allergy development, GINIplus) and (Influence of Lifestyle factors on the development of the Immune System and Allergies in East and West Germany, LISA) to measure PA and sleep. PA was categorised into sedentary, lifestyle and moderate-to-vigorous physical activity (MVPA) referring to Sasaki and Romanzini. Sleep was analysed according to the algorithm developed by Sadeh. Sleep quality was represented by sleep efficiency (SE), sleep onset latency (SOL) and time awake per hour after sleep onset (TAPH). Sleep and activity were additionally reported by diaries. Linear and generalized mixed-effects-models with logit-link with subject specific random intercepts were used stratified by sex and adjusted for confounding variables. RESULTS: Physical activity appears to be associated only with sleep quality the following night. Among female participants, SE improved (ß = 0.12 [95% CI = (0.05; 0.18)]) per 10 minutes increase of MVPA. SOL decreased (OR = 0.83 [95% CI = (0.69; 0.99)]) among male participants with at least 60 min of MVPA per day. Engaging in leisure sport MVPA was associated with higher SE among female (ß = 0.70 [95% CI = (0.22; 1.17)]) and male participants (ß = 0.76 [95% CI = (0.18; 1.34)]). Also, TAPH among female (ß = -0.37 [95% CI = (-0.65; -0.09)]) and SOL among male subjects (OR = 0.70 [95% CI = (0.57; 0.85)]) decreased. Increasing lifestyle activity was related to longer SOL among female (OR = 1.36 [95% CI = (1.15; 1.62)]) and male subjects (OR = 1.32 [95% CI = (1.10; 1.58)]). CONCLUSIONS: In this large population-based sample of German adolescents MVPA and leisure sport improved short term sleep quality, supporting regular PA in adolescents for their health benefit.
