Activity behaviours in British 6-year-olds: cross-sectional associations and longitudinal change during the school transition

BACKGROUND: To explore activity behaviours at school entry, we describe temporal/demographic associations with accelerometer-measured physical activity in a population-based sample of British 6-year-olds, and examine change from age 4-6. METHODS: 712 6-year-olds (308 at both ages) wore Actiheart accelerometers for ≥3 (mean 6.0) days. We derived minutes/day sedentary (<20cpm) and moderate-to-vigorous physical activity (MVPA, ≥460cpm), also segmented across mornings (06:00-09:00), school (09:00-15:00) and evenings (15:00-23:00). Using mixed-effects linear regression, we analyzed associations between temporal/demographic factors and children’s activity intensities at age 6, and change between ages 4-6. RESULTS: 6-year-old children engaged in mean(SD) MVPA: 64.9(25.7) minutes/day (53% met UK guidelines). Girls did less MVPA than boys, particularly during school hours. Children were less active at weekends (vs. weekdays) and more active on spring/summer evenings (vs. winter). Longitudinally, 6-year-old children did less LPA (-44.7 [95%C.I.:-49.9,-39.6] minutes/day) but were more sedentary (30.0 [24.5,35.5]) and engaged in greater MVPA (7.6 [5.6,9.7]) compared with when aged 4. CONCLUSION: Half of 6-year-old children met current activity guidelines; MVPA levels were lower in girls and at weekends. UK children became more sedentary but did more MVPA as they entered formal schooling. PA promotion efforts should capitalise on these changes in MVPA, to maintain positive habits.