The Daily Mile and children's physical activity, mental health and educational performance: a quasi-experimental study in Greater London primary schools.

Objectives To examine associations between The Daily Mile, a school-based active mile intervention, and pupils’ physical activity, mental health, and educational performance. Methods Year 1 pupils (aged 5-6 years) from Greater London primary schools were invited. Schools were allocated to The Daily Mile or non-Daily Mile group based on their reported Daily Mile participation. We measured weekday school hours mean minutes of moderate-to-vigorous physical activity (MVPA) using GENEActiv accelerometers. Other outcomes included time spent sedentary and in light activity, mental health, and educational performance. Multi-level linear regression models examined differences accounting for repeated measurements (day) clustered by pupils-, class-, and school-level, with adjustments for sex, ethnic group, area-level deprivation, and month of assessment. Results A total 1,004 pupils/40 schools were recruited and assessed between October 2021-January 2023; 21 schools/499 pupils comprised The Daily Mile group; 19 schools/505 pupils the non-Daily Mile group. Daily Mile pupils spent 2.2 minutes more in MVPA compared with non-Daily Mile pupils, but the difference was not significant (0.78, 95% CI: -2.14, 3.69). Daily Mile pupils spent less time sedentary and more time in light activity compared with the non-Daily Mile pupils, but not significantly (-5.06, 95% CI: -15.37, 5.26 and 3.27, 95% CI: -4.26, 10.81, respectively). There were no differences in mental health or educational performance. Conclusions We found no associations between The Daily Mile and pupils’ physical activity, mental health, and educational performance. Pupils in our study were in Year 1 with early exposure to the intervention; assessments over longer periods are needed to understand any benefits.