Step to it – can physical activity improve kids’ cognition? A six-month longitudinal study

Background Identifying the relationships among physical activity, cognition, and academic performance in children is important for targeted public health and education initiatives. However, the majority of research has been cross-sectional in nature; we have a limited understanding of the causal direction of these associations. Therefore, aim of this study was to utilise longitudinal data to explore causal relationships among physical activity, cognition and academic performance in elementary school children. Methods Data were sourced from 675 New Zealand children aged 5–11 years. Weekday home, weekday school, and weekend physical activity was measured by multiple pedometer step readings, cognition by four measures from the CNS Vital Signs assessment, and academic performance from the New Zealand Ministry of Education Assessment Tools for Teaching and Learning (asTTle) reading and maths scores. Measures were taken at baseline, two months, and six-month intervals. Data were analysed for 632 students identified with data for at least half of the 27 variables. A generalised linear mixed model was used to investigate changes in physical activity, cognition and academic performance over those three time periods while adjusting for gender, school, age, and socioeconomic status. Results No significant relationships were identified between physical activity and three of the cognitive domains. However, significant, positive relationships were observed between physical activity change at two-months and (1) composite memory change at six-months, (2) maths proficiency change at two-months, and (3) math proficiency change at six-months. Regression coefficients suggest that a child who doubles step count - a 100% increase in PA - will affect a 3.7% improvement in maths proficiency after two months, and after six months affect a 2.6% improvement in maths proficiency and a 4.7% improvement in composite memory. Conclusions This six-month longitudinal analysis identified that an increase physical activity led to small but significant improvements in composite memory and maths proficiency. The small associations suggest that substantial improvements in PA would be required to generate meaningful improvements in cognition and academic achievement. However, timeframes longer than six-months are recommended to identify long-term changes.