title: Effects of a yearlong moderate-intensity exercise and a stretching intervention on sleep quality in postmenopausal women.
abstract: OBJECTIVE
  To examine the effects of a moderate-intensity exercise or stretching intervention and changes in fitness, body mass index, or time spent outdoors on self-reported sleep quality and to examine the relationship between the amount and timing of exercise and sleep quality.
  
  
  METHODS
  A randomized intervention trial.
  
  
  METHODS
  A cancer research center in Seattle, Washington.
  
  
  METHODS
  Postmenopausal, overweight or obese, sedentary women not taking hormone replacement therapy, aged 50 to 75 years, and recruited from the Seattle metropolitan area.
  
  
  METHODS
  A yearlong moderate-intensity exercise (n=87) and a low-intensity stretching (n=86) program.
  
  
  RESULTS
  Among morning exercisers, those who exercised at least 225 minutes per week had less trouble falling asleep (odds ratio [OR]: 0.3, P < or = .05) compared with those who exercised less than 180 minutes per week. However, among evening exercisers, those who exercised at least 225 minutes per week had more trouble falling asleep (OR: 3.3, P < or = .05) compared to those who exercised less than 180 minutes per week. Stretchers were less likely to use sleep medication (OR = 0.4, P < or = .05) and have trouble falling asleep (OR: 0.7, P < or = .10) during the intervention period compared with baseline. A greater than 10% versus a 1% or less increase in maximum O2 consumption over the year was associated with longer sleep duration (P < or = .05), less frequently falling asleep during quiet activities (P < or = .05), and less use of sleep medication (P < or = .05). Reductions in body mass index and increases in time spent outdoors had inconsistent effects on sleep quality.
  
  
  CONCLUSIONS
  Both stretching and exercise interventions may improve sleep quality in sedentary, overweight, postmenopausal women. Increased fitness was associated with improvements in sleep. However, the effect of moderate-intensity exercise may depend on the amount of exercise and time of day it is performed.
authors.affiliation: The Fred Hutchinson Cancer Research Center, Division of Public Health Sciences, Cancer Prevention Research Program, Seattle, Wash 98109-1024, USA.
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
authors.forename: Michael V
authors.initials: MV
authors.lastname: Vitiello
authors.forename: Robert S
authors.initials: RS
authors.lastname: Schwartz
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Aiello
authors.forename: Melinda L
authors.initials: ML
authors.lastname: Irwin
authors.forename: Deborah
authors.initials: D
authors.lastname: Bowen
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D000368:Aged; D015444:Exercise; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D017698:Postmenopause / Q000502:physiology*; D012026:Reflex, Stretch; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000175:diagnosis*; D011795:Surveys and Questionnaires