24-hour movement behaviour and executive function in preschoolers: a compositional and isotemporal reallocation analysis

Adherence to healthy behaviours promotes several health benefits in preschool children, including executive function (EF). Recently, the predictive power of the 24-hour movement behaviour (24h MB) composition on health outcomes has been evidenced; however, its relationship with EF in preschoolers is unknown. Thus, the present study had two objectives: 1) to analyze the associations between the 24h MB composition and EF of preschoolers; and 2) to investigate the theoretical changes in EF when time in different movement behaviours is reallocated. This cross-sectional study was carried out with 123 preschoolers (3-to-5-years-old) of low socioeconomic status. Physical activity (PA) and sedentary behaviour were assessed using an accelerometer for 7 days, sleep time was obtained through interviews with parents, and EF was measured using the Early Tool Box battery. To verify the association between 24h MB and EF, compositional data analysis was used, and for time reallocation, compositional isotemporal substitution analysis was utilized. It was observed that the 24h MB composition was positively associated with EF (p <0.0001; R² = 0.34), and that reallocating 5, 10, 15 or 20 minutes of the time spent on sleep and light PA to moderate-to-vigorous PA, respectively, was associated with significant improvements in EF (p < 0.05). These findings provide hitherto unseen insight into the relationship between 24h MB and EF in preschool children, and warrants consideration for researchers and practitioners seeking to improve EF and PA in preschool children.