title: Influence of the severity of obstructive sleep apnea on nocturnal heart rate indices and its association with hypertension.
abstract: OBJECTIVE
  Both heart rate (HR) and blood pressure parameters provide important information on the pathophysiology of the cardiovascular regulatory mechanisms, and are mainly affected by the autonomic nervous system. We sought to clarify whether the severity of obstructive sleep apnea (OSA) affects nocturnal HRs and whether there is a relationship between nocturnal HRs and the presence of hypertension.
  
  
  METHODS
  We retrospectively reviewed medical records of all patients who performed nocturnal polysomnography with monitoring of HRs, and examined whether there is a relationship among the nocturnal HRs, the severity of OSA and the presence of hypertension.
  
  
  RESULTS
  A total of 540 patients were included in the study. Nocturnal mean and maximal HRs were significantly higher in severe OSA group than in moderate (p=0.002 and p>0.05 in females; p<0.049 and p=0.044, in males, respectively) and mild OSA groups (p<0.001 and p=0.003, respectively in females, p<0.001 and p=0.004, respectively in males); and there was a positive correlation between the nocturnal mean HR and apnea-hypopnea index (Pearson's p=0.504, p<0.001 in female group; Pearson's p=0.254, p<0.001 in male group) and again the nocturnal mean HR and the presence of HT (Spearman's p=0.090, p=0.394 in female group; Spearman's p=0.272, p<0.001 in male group) in both gender groups.
  
  
  CONCLUSIONS
  We found that nocturnal mean and maximal HRs to be associated with severity of OSA and the presence of hypertension. We speculated that increased nocturnal mean and maximal HRs caused by sympathetic nervous system activation in OSA might be one of the mechanisms in explaining the hypertension and OSA association.
authors.affiliation: Clinic of Cardiology, Bayındır Hospital, Ankara, Turkey. ozcanozeke@gmail.com
authors.forename: Ozcan
authors.initials: O
authors.lastname: Ozeke
authors.forename: Mutlu
authors.initials: M
authors.lastname: Güngör
authors.forename: Serap Bilen
authors.initials: SB
authors.lastname: Hızel
authors.forename: Dilek
authors.initials: D
authors.lastname: Aydın
authors.forename: Ozcan
authors.initials: O
authors.lastname: Ertürk
authors.forename: Mehmet Kutlu
authors.initials: MK
authors.lastname: Celenk
authors.forename: Hazım
authors.initials: H
authors.lastname: Dinçer
authors.forename: Gürler
authors.initials: G
authors.lastname: Iliçin
authors.forename: Fuat
authors.initials: F
authors.lastname: Ozgen
authors.forename: Can
authors.initials: C
authors.lastname: Ozer
mesh_terms: D001794:Blood Pressure; D002940:Circadian Rhythm; D005260:Female; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D017286:Polysomnography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*