Childhood physical activity, sedentary behaviours, and sleep in association with academic achievement: compositional data analysis

Background: Physical activity (PA), sedentary behaviours and sleep are codependent, because the time allocated to one behaviour inevitably replaces the time spent on the others within 24 hours. These behaviours have individual associations with learning outcomes but have rarely been studied together as a composite whole.

Purpose: The study examined the association of the 24-hour activity composition on arithmetic and reading fluency in children.

Methods: Volunteered third-grade children in central Finland (N=208, mean age: 9.5 years, 51% girls) participated in the study. Light PA, moderate-to-vigorous PA (MVPA) and sedentary time (ST) were measured using hip-worn accelerometers (ActiGraph GT3X+) and sleep time and screen time with self-reported diaries for seven consecutive days. By combining accelerometer and diary data, a composition of 24-hour activity behaviours (sleep time, non-screen ST, screen time, light PA, MVPA) was formed. Arithmetic fluency was measured with four tasks from the FUNA dyscalculia test battery and reading fluency with the Sentence Verification Task, LUKSU. Linear mixed-effect models were fitted to the data.

Results: The 24-hour activity composition was significantly associated with reading fluency, but not with arithmetic fluency. The ratio of sleep time to other activities was directly associated with reading fluency (β=0.73, p<0.05).

Conclusions: Replacing time spent on any other activities with sleep may enhance reading fluency.

Practical implications: In order to support reading fluency, parents should be educated about the important role of sufficient sleep in supporting children´s learning outcomes and encouraged to ensure that children get enough sleep.

Funding: Finnish Ministry of Education and Culture.