The dependence of onset and duration of sleep on the circadian rhythm of rectal temperature

Abstract

Abstract. The sleep-wake cycle and the circadian rhythm of rectal temperature were recorded in subjects who lived sing[y in an isolation unit. In 10 subjects, the freerunning rhythms remained internally synchronized, 10 other subjects showed internal desynchronization. Times of onset and end of bedrest ("sleep") were determined in each cycle and referred to the phase of the temperature rhythm. In the synchronized subjects, onset of sleep occurred, on the average, 1.34 h before the minimum of temperature, and end of sleep 6.94h thereafter, with narrow distributions. The desynchronized subjects had a broad bimodal distribution of sleep onsets (peaks 6.3 and 1.3 h before the minimum); the duration of sleep varied between more than 15 h when sleep began about 10 h before the temperature minimum, and less than 4 h when sleep began several hours after the minimum. The dependence of sleep duration on body temperature is interpreted as a continuing action of the coupling forces between the two rhythms after mutual synchronization is lost.

Circadian rhythms in glucose and lipid metabolism in nocturnal and diurnal mammals

“…Adapted from Crumbley and Burris (2011) and Mohawk et al (2012). nocturnal rodents show elevated energy expenditure and body temperature in their wake/feeding period in association with behavioral arousal, increased locomotion and food consumption at night (Alberts et al, 2006;Yang et al, 2010). Both core body temperature and energy expenditure display rhythms over the daily 24 h periods that are oppositely phased between diurnal and nocturnal animals (Cuesta et al, 2009;Krauchi and Wirz-Justice, 2001;Piccione et al, 2005;Zulley et al, 1981). The other determinants of energy expenditure are behavioral arousal and physical exercise, two activities that are also in anti-phase between nocturnal and diurnal species.…”

Circadian Clues to Sleep Onset Mechanisms

“…Sleep is usually initiated on the declining portion of the CBT curve in the evening (Czeisler et al 1980;Zulley et al 1981). It is most likely to occur when CBT is declining at its maximum rate (Campbell and Broughton 1994).…”

Reduction of human sleep duration after bright light exposure in the morning

“…The circa&an influence on sleep duration is also present under Corre~pondeme D J D0k, Department of Biological Psychiatry and Department of Zoology. Umverslt~ conditions of temporal isolation Longest sleep episodes occur when sleep is mltmted near the maximum of the body temperature rhythm whereas shortest sleep eplsode,~ start near the minimum of the body temperature rhythm [6,20] In the two-process model of sleep regulation [5,9] both the homeostatic and the cxrca&an aspects of sleep duration are accounted for During wakefulness a regulatory variable (S) increases until an upper threshold is reached and sleep is imtiated During sleep S decays exponentially untd a lower threshold is reached This results m the transition from sleep to wakefulness. The time course of S as reflected in the EEG power density (0.25 15.0 Hz) during sleep Under normal condataons waking up occurs on the Nsmg part of the lower threshold which coincides with the rising part of the body temperature curve.…”