title: Children's sleep and autonomic function: low sleep quality has an impact on heart rate variability.
abstract: OBJECTIVE
  Short sleep duration and poor sleep quality in children have been associated with concentration, problem behavior, and emotional instability, but recently also with disrupted autonomic nervous function, which predicts cardiovascular health. Heart rate variability (HRV) was used as noninvasive indicator of autonomic function to examine the influence of sleep.
  
  
  METHODS
  Cross-sectional and longitudinal observational study on the effect of sleep on HRV.
  
  
  METHODS
  Belgian children (5-11 years) of the ChiBS study in 2010 (N = 334) and 2011 (N = 293).
  
  
  METHODS
  N/A.
  
  
  METHODS
  Sleep duration was reported and in a subgroup sleep quality (efficiency, latency, awakenings) was measured with accelerometry. High-frequency (HF) power and autonomic balance (LF/HF) were calculated on supine 5-minute HRV measurements. Stress was measured by emotion and problem behavior questionnaires. Sleep duration and quality were used as HRV predictors in corrected cross-sectional and longitudinal regressions. Stress was tested as mediator (intermediate pathway) or moderator (interaction) in sleep-HRV associations.
  
  
  RESULTS
  In both cross-sectional and longitudinal analyses, long sleep latency could predict lower HF (parasympathetic activity), while nocturnal awakenings, sleep latency, low sleep efficiency, and low corrected sleep duration were related to higher LF/HF (sympathetic/parasympathetic balance). Parental reported sleep duration was not associated with HRV. The significances remained after correction for stress. Stress was not a mediator, but a moderator (enhancer) in the relationship between sleep quality and HRV.
  
  
  CONCLUSIONS
  Low sleep quality but not parent-reported low sleep duration leads to an unhealthier heart rate variability pattern (sympathetic over parasympathetic dominance). This stresses the importance of good sleep quality for cardiovascular health in children.
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Michels
authors.forename: Els
authors.initials: E
authors.lastname: Clays
authors.forename: Marc
authors.initials: M
authors.lastname: De Buyzere
authors.forename: Barbara
authors.initials: B
authors.lastname: Vanaelst
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Henauw
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sioen
mesh_terms: D056044:Actigraphy; D001341:Autonomic Nervous System / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000503:physiopathology; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires
keywords: Sleep actigraphy; children; short-term heart rate variability; stress; sympathetic/parasympathetic balance