title: Excessive daytime sleepiness does not correlate with sympathetic nervous system activation and arterial stiffening in patients with mild-to-moderate obstructive sleep apnoea: A proof-of-principle study.
abstract: BACKGROUND
  Increased arterial stiffness and sympathetic nervous system activity, independent markers of cardiovascular risk, are common in patients with severe obstructive sleep apnoea, who have excessive daytime sleepiness. Among patients with mild-to-moderate obstructive sleep apnoea, however, it remains unknown whether arterial stiffness and/or increased sympathetic nervous system activity correlate with excessive daytime sleepiness.
  
  
  METHODS
  We measured heart rate variability, as an index of autonomic nervous system activity, and arterial stiffness index, as a marker of vascular damage and cardiovascular risk, in 56 men aged 18 to 75years, with mild-to-moderate obstructive sleep apnoea, and matched into two groups, "sleepy" (Epworth Sleepiness Scale≥10) and "non-sleepy" (Epworth Sleepiness Scale<10).
  
  
  RESULTS
  We found no association of excessive daytime sleepiness with sympathetic nervous system activation (very low frequency power 18,947±11,207ms2vs 15,893±8,272ms2, p=0.28; low frequency (LH) power 17,753±8,441ms2vs 15,414±5,666ms2, p=0.26; high frequency (HF) power 7,527±1,979ms2vs 8,257±3,416ms2, p=0.36; LF/HF ratio 3.04±1.37 vs 2.55±1.01, p=0.15) and mean arterial stiffness index (6.97±0.83 vs 7.26±0.66, p=0.18) in mild-to-moderate obstructive sleep apnoea patients.
  
  
  CONCLUSIONS
  Symptoms of excessive daytime sleepiness are not associated with sympathetic nervous system activation and arterial stiffness in male subjects with mild-to-moderate obstructive sleep apnoea.
authors.affiliation: Clinica dell'Ipertensione Arteriosa, Dept. of Medicine-DIMED, University of Padua, Italy. Electronic address: valeria.bisogni@hotmail.it.
authors.forename: Valeria
authors.initials: V
authors.lastname: Bisogni
authors.affiliation: Clinica dell'Ipertensione Arteriosa, Dept. of Medicine-DIMED, University of Padua, Italy.
authors.forename: Martino F
authors.initials: MF
authors.lastname: Pengo
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Lane Fox Respiratory Unit/Sleep Disorders Centre, London, UK.
authors.forename: Panagis
authors.initials: P
authors.lastname: Drakatos
authors.affiliation: Clinica dell'Ipertensione Arteriosa, Dept. of Medicine-DIMED, University of Padua, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maiolino
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Lane Fox Respiratory Unit/Sleep Disorders Centre, London, UK.
authors.forename: Brian
authors.initials: B
authors.lastname: Kent
authors.affiliation: Clinica dell'Ipertensione Arteriosa, Dept. of Medicine-DIMED, University of Padua, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Rossitto
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Lane Fox Respiratory Unit/Sleep Disorders Centre, London, UK; King's College London, Faculty of Life Sciences and Medicine, London, UK.
authors.forename: Joerg
authors.initials: J
authors.lastname: Steier
authors.affiliation: Clinica dell'Ipertensione Arteriosa, Dept. of Medicine-DIMED, University of Padua, Italy.
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017156:Photoplethysmography / Q000379:methods; D000075082:Proof of Concept Study; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D059289:Vascular Stiffness / Q000502:physiology*; D055815:Young Adult
keywords: Arterial stiffness; Daytime sleepiness; Heart rate variability; Obstructive sleep apnoea