Movement behaviors in short versus adequate nocturnal sleepers: A compositional analysis of preschoolers

Background: Accruing adequate daily amounts of time spent on movement behaviors (physical activity (PA), sedentary behavior (SB), and sleep) in childhood has been associated with positive short and long-term health outcomes. Nonetheless, how waking time is distributed across PA and SB among preschoolers who are short and adequate sleepers at night is unknown. Aim: This study investigated: (1) if there are differences in a movement behaviors composition among adequate and short nocturnal sleepers; and (2) the association between preschoolers' time spent in PA, SB, and sleep among adequate and short nocturnal sleepers. Methods: A total of 270 preschoolers (132 boys; 3.97 ± 0.81 years old; 15.48 ± 1.62 kg/m²) participated in this study. PA and SB were assessed using accelerometry (model wGT3X). Sleep duration was assessed through a parental-proxy interview, and preschoolers were stratified as short and adequate sleepers, according to attendance to international sleep duration guidelines. Compositional data analysis was used to explore the time-use patterns of behaviors among adequate and short sleepers. Results: Short sleepers spent 64 min less time asleep, accumulated 32 min in more sedentary time (p =.005, Cohen's d = 0.36, Bayes Factor: 6.17), and 24 min more in light PA (p =.0005, Cohen's d = 0.44, Bayes Factor: 46.37) compared to adequate sleepers. Conclusions: Being a short sleeper was associated with greater time spent in SB and light PA during their waking hours. The health implications of movement behaviors composition among short sleep preschoolers should be further investigated.