title: The heart rate response to exercise is blunted in patients with sleep-related breathing disorder.
abstract: BACKGROUND
  This study addressed the hypothesis that cardiovascular reactivity during graded bicycle exercise is influenced by a coexisting sleep-related breathing disorder (SRBD).
  
  
  METHODS
  Blood pressure and heart rate were assessed at rest and during graded exercise (110 W and maximal load) in 1,149 patients of a Sleep Disorders Center. The degree of SRBD, and potential confounders, including blood gases and pulmonary function, were determined.
  
  
  RESULTS
  Maximal exercise capacity tended to decrease with SRBD activity (p = 0.07). The heart rate reactivity was blunted and reduced by -0.07 and -0.09 beats/min for every SRBD unit at 110 W (p < 0.001) and at maximal load (p < 0.001), respectively. Systolic and diastolic blood pressure reactivity at maximal load were positively associated with SRBD severity. These associations were independent of possible confounders.
  
  
  CONCLUSIONS
  SRBD is associated with reduced physical working capacity and a modified hemodynamic response to exercise.
authors.affiliation: Sleep Disorders Center, Pulmonary Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden. ludger.grote@lungall.gu.se
authors.forename: Ludger
authors.initials: L
authors.lastname: Grote
authors.forename: Jan
authors.initials: J
authors.lastname: Hedner
authors.forename: Jörg Hermann
authors.initials: JH
authors.lastname: Peter
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*