Skip to main content

Free Content Changes in sleepiness and body temperature precede nocturnal sleep onset: Evidence from a polysomnographic study in young men

Download Article:

You have access to the full text article on a website external to Ingenta Connect.

Please click here to view this article on Wiley Online Library.

You may be required to register and activate access on Wiley Online Library before you can obtain the full text. If you have any queries please visit Wiley Online Library

Abstract:

Recent research has shown a close temporal relationship between the nocturnal decrease in rectal core temperature and the initiation of sleep. However, there is not yet a clear temporal relationship between changes in peripheral and core temperatures and nocturnal sleep onset. We recorded body temperatures in 14 adult males (age±SEM=22.1±0.6 y), who attended the sleep laboratory for an adaptation night and two counterbalanced experimental sessions. Subjects self-selected lights-out on one experimental night (the Habitual Sleep condition). To determine the relationship between body temperature changes and sleep onset, lights out was delayed until after 01.00 hours on the other experimental night (Delayed Sleep condition). Individual datasets in both conditions were expressed relative to the time of sleep onset in the Habitual Sleep condition only, so that they were aligned at identical clock times. Saliva samples confirmed that mean dim light melatonin onset (DLMO) occurred at 00.10±00.16 hours in the Delayed Sleep condition, which was after habitual sleep onset at 23.44±00.08 hours. Rectal core temperature (Tc) decreased significantly over time only in the Habitual Sleep condition ( P < 0.01). For the 20 min before habitual sleep onset, Delayed Sleep Tc was on average 0.1°C higher than Tc in the Habitual Sleep condition ( P < 0.01). The greater decline in Habitual Sleep Tc was associated with significantly increased peripheral hand and foot skin temperatures before sleep (both P < 0.05). Subjective sleepiness measures were higher in the Habitual Sleep onset condition from 150 min prior until sleep onset ( P < 0.01). From these results it is reasonable to infer that a sequence of thermoregulatory and sleep propensity changes occur before, but are associated with habitual sleep onset, as the changes are significantly attenuated if sleep is delayed.

Keywords: body temperature; dim light melatonin onset; human; polysomnography; sleep onset; sleep propensity

Document Type: Original Article

DOI: https://doi.org/10.1046/j.1365-2869.1998.00112.x

Affiliations: 1: Department of Physiology, University of Adelaide, South Australia, Australia 2: Centre for Sleep Research, The University of South Australia, South Australia, Australia

Publication date: 1998-09-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more