Associations Between Physical Activity and Sedentary Time with Sleep Duration and Sleep Quality in Adolescents

Background: To examine the cross-sectional associations between objectively assessed physical activity and sedentary time, and both objectively and subjectively assessed sleep parameters (e.g., duration and quality) among Australian adolescents, including weekdays and weekends. Methods: Baseline data from the TransformUs Secondary effectiveness trial involved 193 adolescents (mean age 14.8 years) from Victoria, Australia. Participants self-reported bedtime and wake-up times on school nights and weekends, as well as sleep quality using the Adolescent Sleep Wake Scale. The wrist-worn ActiGraph GT9X was used to collect 24-hour activity data for over 1 week (minimum of 16 hours, at least 3 days) to assess moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary time, and sleep parameters, including total sleep time (TST), sleep efficiency, sleep latency, and wake after sleep onset (WASO). Linear regression models examined associations between physical activity, sedentary time, and sleep parameters. Results: Sedentary time was inversely associated with self-reported sleep quality, and with objectively assessed weekday sleep duration and TST. No significant associations were observed between LPA, MVPA, and sleep parameters. Conclusions: These findings highlight the detrimental link between higher sedentary time and poor sleep quality and duration among adolescents, reinforcing the need to reduce sedentary behavior as a key intervention strategy for improving sleep health. Future prospective studies are needed to better understand temporal associations and the types of behaviour adolescents are engaging in when they are sedentary.