title: Influence of sleep duration on cortical oxygenation in elderly individuals.
abstract: OBJECTIVE
  Short sleep duration is a risk factor for cardiovascular diseases. Cerebral blood flow and its regulation are affected by pathological conditions commonly observed in the elderly population, such as dementia, atherosclerosis, diabetes mellitus (DM), stroke, and hypertension. The purpose of this study was to examine the influence of sleep duration on cortical oxygenated hemoglobin (OxyHb) using near-infrared spectroscopy (NIRS).
  
  
  METHODS
  Seventy-three individuals (age, 70.1 ± 3.9 years, 51 men and 22 women) participated in this study. Cortical OxyHb levels were measured with NIRS. We evaluated age, body mass index (BMI), smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia using a questionnaire. Blood pressure was measured using plethysmography.
  
  
  RESULTS
  Peak OxyHb and area under the NIRS curve significantly decreased in participants with sleep duration <7 h compared with those with sleep duration ≥7 h (0.136 ± 0.212 mM·mm vs 0.378 ± 0.342 mM·mm, P = 0.001; 112.0 ± 243.6 vs 331.7 ± 428.7, P  = 0.012, respectively). Sleep duration was significantly correlated with peak OxyHb level and area under the NIRS curve (r = 0.378, P  = 0.001; r = 0.285, P  = 0.015, respectively). Multiple regression analysis, including age, BMI, sex, smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia revealed that sleep duration was the only significant independent factor associated with peak OxyHb and area under the NIRS curve (β = 0.343, P  = 0.004; β = 0.244, P  = 0.049, respectively), and smoking status was independently correlated with time to the peak OxyHb (β = -0.319, P  = 0.009).
  
  
  CONCLUSIONS
  Sleep duration may be an important factor that influences cortical oxygenation in the elderly population.
authors.affiliation: Chubu University Graduate School of Life and Health Sciences, Aichi, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Sleep Medicine, Nagoya University Graduate School of Medicine, Aichi, Japan.|Education and Training Center of Medical Technology, Chubu University, Aichi, Japan.
authors.forename: Seiko
authors.initials: S
authors.lastname: Miyata
authors.affiliation: Education and Training Center of Medical Technology, Chubu University, Aichi, Japan.
authors.forename: Motoo
authors.initials: M
authors.lastname: Ando
authors.affiliation: Chubu University Graduate School of Life and Health Sciences, Aichi, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Matsuoka
authors.affiliation: Department of Internal Medicine, National Hospital Organization Suzuka Hospital, Mie, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Yasuma
authors.affiliation: Department of Psychiatry, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Iwamoto
authors.affiliation: Institutes of Innovation for Future Society, Nagoya University, Aichi, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kawano
authors.affiliation: Department of Psychiatry, Nagoya University Graduate School of Medicine, Aichi, Japan.|Seichiryo Hospital, Aichi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Banno
authors.affiliation: Department of Psychiatry, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Ozaki
authors.affiliation: Chubu University Graduate School of Life and Health Sciences, Aichi, Japan.|Education and Training Center of Medical Technology, Chubu University, Aichi, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Noda
mesh_terms: D000368:Aged; D000375:Aging / Q000378:metabolism / Q000502:physiology*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010108:Oxyhemoglobins / Q000378:metabolism*; D012890:Sleep / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D010108:Oxyhemoglobins
keywords: cerebral blood flow; cortical oxygenation; elderly; sleep duration; smoking