RT Journal Article SR Electronic T1 Falling asleep: the determinants of sleep latency JF Archives of Disease in Childhood JO Arch Dis Child FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 686 OP 689 DO 10.1136/adc.2009.157453 VO 94 IS 9 A1 G M Nixon A1 J M D Thompson A1 D Y Han A1 D M O Becroft A1 P M Clark A1 E Robinson A1 K E Waldie A1 C J Wild A1 P N Black A1 E A Mitchell YR 2009 UL http://adc.bmj.com/content/94/9/686.abstract AB Background: Difficulty falling asleep (prolonged sleep latency) is a frequently reported problem in school-aged children.Aims: This study aimed to describe the distribution of sleep latency and factors that influence its duration.Methods: 871 children of European mothers were recruited at birth. 591 (67.9%) children took part in the follow-up at 7 years of age. Sleep and daytime activity were measured objectively by an actigraph worn for 24 h.Results: Complete sleep data were available for 519 children (87.8%) with a mean age of 7.3 years (SD 0.2). Median sleep latency was 26 minutes (interquartile range 13–42). Higher mean daytime activity counts were associated with a decrease in sleep latency (−1.2 minutes per 102 movement count per minute, p = 0.05). Time spent in sedentary activity was associated with an increase in sleep latency (3.1 minutes per hour of sedentary activity, p = 0.01).Conclusions: These findings emphasise the importance of physical activity for children, not only for fitness, cardiovascular health and weight control, but also for promoting good sleep.