0014 Time to Step Up: The Role of Circadian Misalignment on Adolescent Physical Activity Metrics

Abstract Introduction Circadian misalignment, the discrepancy between internal circadian timing and sleep timing, impacts overall health and well-being. While past research emphasizes the connection between physical activity and sleep duration, we aim to examine differences in physical activity levels and abilities in adolescents experiencing experimentally manipulated circadian-aligned versus misaligned sleep conditions. Methods 29 night-owl adolescents underwent both aligned (12:30am-9:30am) and misaligned sleep (9:30pm-6:30am) for five nights each, with order randomized. To determine adherence to study protocols, wrist accelerometers tracked sleep duration and timing and waist accelerometers measured physical activity. After each experimental period, participants completed the 6-minute walk test and a sit-to-stand test. Repeated measures t-tests were used to assess the impact of the circadian timing condition on minutes in sedentary behavior, minutes in moderate-to-vigorous physical activity (MVPA), 6-minute walk distance, and sit-to-stand repetitions. Results Participants in the aligned condition significantly outperformed the misaligned group in sit-to-stand repetitions (M=24.10, SD=8.978; M=19.72, SD=6.524, respectively; p=0.003, d=0.616). Additionally, 6-min walk results revealed a significant difference, with participants in the aligned condition walking significantly farther than the control group (M=0.2952, SD=0.13095; M=0.2331, SD=0.10674, respectively; p=0.011, d=0.503). There was no significant difference between aligned and misaligned conditions in MVPA or sedentary behavior. Conclusion Participants undergoing circadian alignment had significantly better performance in walking and sitting tasks compared to when they were misaligned; there was no impact of circadian timing on physical activity levels across the week. These results could have significant implications for how teen athletes train and compete. Specifically, aligning teen athlete’s school and sport training and competition schedules with their circadian rhythm might lead to better performance. Support (if any)