Falling asleep: the determinants of sleep latency

Arch Dis Child. 2009 Sep;94(9):686-9. doi: 10.1136/adc.2009.157453. Epub 2009 Jul 24.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Exercise / physiology
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Polysomnography
  • Prospective Studies
  • Regression Analysis
  • Seasons
  • Sleep Initiation and Maintenance Disorders / diagnosis
  • Sleep Initiation and Maintenance Disorders / etiology*
  • Sleep Initiation and Maintenance Disorders / psychology