title: Age changes in timing and 24-hour distribution of self-reported sleep.
abstract: OBJECTIVE
  Aging has been associated with increased nocturnal awakenings, increased napping, earlier bedtimes and wake-up times, and more regular sleep-wake schedules. These patterns have often been ascribed to both psychosocial and medical factors, but nearly all studies to-date have been cross-sectional.
  
  
  METHODS
  The authors present self-reported sleep data from 31 elderly subjects followed over a decade.
  
  
  RESULTS
  With aging, the number of nightly awakenings and daytime napping increased over time. Exploratory analyses suggested that individuals who lived with another person had earlier bedtimes, later wake-up times, and greater daytime napping. Intervening medical comorbidities also appeared to be associated with increased napping.
  
  
  CONCLUSIONS
  These results confirm previous cross-sectional studies and suggest a complex biopsychosocial matrix for the timing and placement of sleep in elderly persons within the 24-hour day.
authors.affiliation: Program in Sleep, Aging, and Chronobiology, Wesley Woods Health Center, Emory University Medical School, 1841 Clifton Road NE, Atlanta, GA 30329, USA. dbliwis@emory.edu
authors.forename: Donald L
authors.initials: DL
authors.lastname: Bliwise
authors.forename: Farzaneh Pour
authors.initials: FP
authors.lastname: Ansari
authors.forename: Laura-Beth
authors.initials: LB
authors.lastname: Straight
authors.forename: Kathy P
authors.initials: KP
authors.lastname: Parker
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D020178:Sleep Disorders, Circadian Rhythm / Q000453:epidemiology*; D013997:Time Factors