Temporal and bidirectional associations of sleep-wake behavior in adolescentes

This study investigated the temporal and bidirectional associations between wake behaviors - sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) - and sleep patterns, including total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), sleep fragmentation (SF), time to bed (TTB), and time out of bed (TOB). A total of 178 adolescents (aged 15-18 years, 50.56% boys) were assessed using accelerometry over 24 hours for seven consecutive days. Multilevel linear models with random intercept were used for longitudinal analysis of bidirectional and temporal associations, adjusted for sex, age, body mass index, socioeconomic level, and day of the week. At the between-subject level, higher SB, LPA and MVPA were associated with lower TST, while higher LPA was associated with higher TTB. Higher TST was associated with lower SB, and higher TTB was associated with higher SB. At the within subject level, higher SB and LPA were associated with lower TST and WASO, and higher TST, TTB and TOB were associated with lower SB. A consistent routine for going to bed and getting up at appropriate times can enhance the availability of time for PA by reducing the time involved in SB.