title: High or increasing levels of physical activity protect women from future insomnia.
abstract: OBJECTIVE
  There is a lack of evidence about the impact of physical activity on insomnia based on representative samples with a long-term follow-up. The aim of this study was to assess the impact of physical activity on insomnia incidence, as well as the impact of changes in leisure-time physical activity on insomnia in women.
  
  
  METHODS
  The study included a population-based sample of 5062 women aged >20 years who responded to questionnaires in 2000 and 2010. Insomnia was defined as experiencing severe or very severe problems in falling asleep, maintaining sleep, or experiencing early morning awakenings, together with daytime sleepiness or fatigue. Physical activity was categorized as low, medium, or high level at baseline and at follow-up.
  
  
  RESULTS
  After adjusting for age, body mass index, smoking, alcohol dependence, snoring status, level of education, and psychological distress, the adjusted odds ratio (OR) (95% confidence interval) for incident insomnia in women who increased from a low to a medium or high level of physical activity was 0.53 (0.3-0.94) and 0.17 (0.03-0.81), respectively, as compared to women with a low activity level on both occasions. Women remaining on a medium activity level or increasing to a high activity level had an OR of 0.53 (0.35-0.83) and 0.36 (0.21-0.64) and the OR of those decreasing from a high level to a medium level or remaining on a high activity level on both occasions was 0.37 (0.21-0.66) and 0.3 (0.16-0.54) respectively.
  
  
  CONCLUSIONS
  Women maintaining higher levels or increasing their level of leisure-time physical activity over the 10-year period were partly protected from self-reported insomnia.
authors.affiliation: Department of Neuroscience, Physiotherapy, Uppsala University, Box 593, 75124 Uppsala, Sweden. Electronic address: soren.sporndly-nees@neuro.uu.se.
authors.forename: Søren
authors.initials: S
authors.lastname: Spörndly-Nees
authors.affiliation: Department of Neuroscience, Physiotherapy, Uppsala University, Box 593, 75124 Uppsala, Sweden.
authors.forename: Pernilla
authors.initials: P
authors.lastname: Åsenlöf
authors.affiliation: Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Lindberg
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008875:Middle Aged; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D011795:Surveys and Questionnaires
keywords: Epidemiology; Physical activity; Public health; Risk factors; Sleep disorder