Longitudinal associations of sedentary time and physical activity duration and patterns with cognitive development in early childhood

Importance: Sedentary behaviour and physical activity are important to consider for optimal cognitive development. Few studies have examined patterns (i.e., bouts/breaks) of these behaviours in early childhood and longitudinal associations with cognitive outcomes. Objectives: Examine: 1) changes in total duration and patterns of sedentary time and physical activity across three time-points, separated by approximately six-months; and 2) longitudinal associations of sedentary time and physical activity (i.e., duration and patterns) with cognitive development in early childhood. Method: Participants included 100 children aged 2.5-5.0 years at time-point 1. Participants wore ActiGraph accelerometers and completed measures of cognition: inhibitory control (Fish-Shark Go/No-Go task), working memory (Nebraska Barnyard task), and general cognitive ability (Woodcock-Johnson III test battery) at two/three time-points. Multilevel growth modelling was used to examine total duration and patterns (i.e., bouts and breaks) of sedentary behaviour and physical activity over time and longitudinal associations with cognitive outcomes. Results: Total sedentary time decreased (beta [95% CI] = -9.24 [-15.76, -2.72]; beta represents estimated change per year), whereas time spent in moderate-to-vigorous-intensity physical activity (MVPA; 5.65 [1.89, 9.41]) increased over time. A significant decrease in time spent in >= 10-min sedentary bouts (-9.76 [-13.56, -5.96]), and significant increases in sedentary breaks (13.41 [7.18, 19.63]) and time spent in 1-3-min (2.56 [0.96, 4.15]) and 3-5-min bouts of MVPA (0.86 [0.33, 1.38]) were also found. There was minimal evidence of longitudinal associations between the accelerometry variables and cognitive outcomes. Conclusions: The observed changes in sedentary time and MVPA over time are promising for child health. Nevertheless, no meaningful associations with cognitive outcomes were found. Future studies with larger sample sizes should investigate whether specific types of activities that children engage in are associated with cognitive development overtime. Overall, this body of evidence could help inform future updates of guidelines concerning patterns of activity and health in the early years.