Passive body heating ameliorates sleep disturbances in patients with vascular dementia without circadian phase-shifting

Am J Geriatr Psychiatry. 2005 May;13(5):369-76. doi: 10.1176/appi.ajgp.13.5.369.


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.

Conclusion: PBH may have a sleep-promoting effect by intervening in the thermoregulatory and autonomic systems in elderly IPs with vascular dementia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Body Temperature Regulation* / physiology
  • Circadian Rhythm* / physiology
  • Dementia, Vascular / physiopathology
  • Dementia, Vascular / therapy*
  • Female
  • Heating*
  • Humans
  • Immersion / physiopathology
  • Lighting
  • Male
  • Melatonin / blood
  • Parasympathetic Nervous System / physiopathology
  • Polysomnography
  • Reaction Time / physiology
  • Sleep Initiation and Maintenance Disorders / physiopathology
  • Sleep Initiation and Maintenance Disorders / therapy*
  • Statistics as Topic
  • Treatment Outcome


  • Melatonin