title: Age difference in heart rate changes associated with micro-arousals in humans.
abstract: OBJECTIVE
  Heart rate (HR) is known to change in association to micro-arousals (MA) during sleep. The aim of the present study was to evaluate the effect of age on HR variations associated with MA.
  
  
  METHODS
  Thirty-two healthy subjects underwent one night of polysomnographic recording. They were divided into two groups of 16 subjects according to age i.e. young (20-35 years) and middle-aged (50-65 years). The R-R intervals were calculated for 11 heart beats (10 intervals) before and 15 heart beats after the onset of MA.
  
  
  RESULTS
  HR changes associated with MA were characterized by a tachycardia followed by a bradycardia in both young- and middle-aged subjects. However, middle-aged subjects showed a significant reduction in the amplitude of both tachycardia and bradycardia as compared to young subjects.
  
  
  CONCLUSIONS
  This study revealed an age-related reduction in the amplitude of the HR changes associated with MA. These results may reflect a decline in parasympathetic functions and a higher risk of cardiovascular diseases with advancing age.
authors.affiliation: Centre d'étude du sommeil et des rythmes biologiques, Hôpital du Sacré-Coeur de Montréal, 5400 boul. Gouin Ouest, Quebec, Montreal, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Gosselin
authors.forename: M
authors.initials: M
authors.lastname: Michaud
authors.forename: J
authors.initials: J
authors.lastname: Carrier
authors.forename: G
authors.initials: G
authors.lastname: Lavigne
authors.forename: J
authors.initials: J
authors.lastname: Montplaisir
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001143:Arousal / Q000502:physiology*; D004562:Electrocardiography; D004569:Electroencephalography; D004585:Electrooculography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012016:Reference Values; D012890:Sleep / Q000502:physiology*