title: Passive body heating ameliorates sleep disturbances in patients with vascular dementia without circadian phase-shifting.
abstract: OBJECTIVE
  This study investigated the sleep-promoting, thermoregulatory, and circadian phase-shifting actions of passive body heating (PBH) in elderly insomniac patients (IPs) with mild-to-moderate vascular dementia.
  
  
  METHODS
  Thirteen elderly IPs with vascular dementia (mean age 76.9 years; male/female ratio 2/11) were subjected to a PBH trial session. This session comprised a 3-day baseline period, 2-day PBH period, and 1-day post-PBH period. In the PBH period, the subjects received PBH (immersion in hot water about 40.0 degrees C to mid-thorax level) for 30 minutes beginning 2 hours before bedtime. Sleep-waking, estimated by actigraph, core body temperature (cBT), and heart rate variability were continuously monitored. Dim-light melatonin-onset time (DLMO) was determined in the baseline and post-PBH periods.
  
  
  RESULTS
  PBH significantly improved subjects' sleep quality; sleep latency decreased; sleep efficiency increased; and wake time after sleep onset decreased. These trends were more prominent in the latter half of the sleep time. PBH induced a rapid cBT elevation of approximately 0.80 degrees C, on average, followed by enhanced heat loss (DeltacBT: difference in cBT between just after the PBH and bedtime), lasting 1.5 hours before sleep. There was a significantly positive correlation between DeltacBT and sleep latency. PBH induced no significant phase shift in DLMO. Heart-rate variability data showed that PBH induced parasympathomimetic action during sleep time in the subjects.
  
  
  CONCLUSIONS
  PBH may have a sleep-promoting effect by intervening in the thermoregulatory and autonomic systems in elderly IPs with vascular dementia.
authors.affiliation: Department of Geriatric Psychiatry, Kyowa Hospital, Akita, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Mishima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hozumi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shimizu
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hishikawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Mishima
mesh_terms: D000368:Aged; D001833:Body Temperature Regulation / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D015140:Dementia, Vascular / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006361:Heating; D006801:Humans; D007101:Immersion / Q000503:physiopathology; D008029:Lighting; D008297:Male; D008550:Melatonin / Q000097:blood; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D017286:Polysomnography; D011930:Reaction Time / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology / Q000628:therapy*; D013223:Statistics as Topic; D016896:Treatment Outcome
chemical_list: D008550:Melatonin