Sleep and Body Temperature in “Morning” and “Evening” People

Abstract

Summary: Three groups of young, normal sleepers were selected as morning types (MTs).1 evening types (ETs), and neither types (NTs) as determined by the Horne and Ostberg questionnaire. Sleep and rectal temperatures were recorded under three conditions: baseline nights (Cond. 1), sleep on the recovery day after 1 night of sleep deprivation (Cond. 2), and sleep on the recovery night after I night and 1 day of sleep deprivation (Cond. 3). During Conds. 1 and 3, when sleep schedules were self-determined, sleep structure and body temperature were similar in MTs, and ETs, and NTs. During Condo 2, however, MTs had poorer sleep, i.e., a smaller percentage of REM sleep and more awakenings, than ETs. This difference can be related to the evolution of temperature during Condo 2; i.e., a temperature increase in the MT and NT and a decrease in the ET. Key Words: Human sleep--Morning type-Evening type-Sleep deprivation-Temperature evolution.Classifying individuals as morning types (MTs), evening types (ETs), and neither types (NTs) is based, in addition to everyday observations, on (a) reported sleep schedules (1), (b) subjectively assessed arousal (2,3), and (c) the time of temperature peak (1). Other circadian variables, such as the excretion of catecholamine (norepinephrine) (2), are not significant indicators of type.All studies differentiating MTs from ETs have utilized diurnal measurements. As far as we know, only Webb and Bonnet (4) have studied nocturnal sleep. However, they clearly differentiated only two groups, MTs and ETs, and studied these two groups only in relation to their sleep schedules and the subjective quality of their sleep. Except for the work of Breithaupt et al. (5), few studies have been devoted to the influence of MT/ET typology on sleep when sleep is delayed.The present study investigates the internal sleep structure of MTs and ETs in relation to the temporal evolution of body temperature. METHODSNineteen healthy young subjects (aged from 20 to 26 years) selected by means of a questionnaire (1) participated as paid volunteers. All subjects were satisfied with both their sleep and diurnal vigilance and had agreed to keep a 2-week sleep log.

Increased Homeostatic Response to Behavioral Sleep Fragmentation in Morning Types Compared to Evening Types

“…All-night spectral power was calculated over NREM sleep stages (excluding stage 1) for 24 one-Hz frequency bins identified by their lower boundary value. Spectral power was averaged for 6 frequency bands (SWA [1-5 Hz], theta [4][5][6][7][8], alpha [8][9][10][11][12], low sigma [12][13][14], high sigma [14-16 Hz], and beta [16][17][18][19][20][21][22][23][24]) and then averaged in 2-hour periods for the sleep episode of each night. Two-hour periods were calculated according to real time (clock time) and are also identified by their lower boundary value.…”

“…In chronotypes, differences in daytime sleep have been evaluated following a night of sleep deprivation. Some researchers have found that daytime sleep was more affected in morning types than in evening types, 20,21 while another study found larger changes between nighttime and daytime sleep cycles and EEG activity in evening types than in morning types. 22 In all these studies, the relationship between circadian phase and the timing of the sleep episode was modified; such modification is known to alter both sleep structure and expression of SWA.…”

Individual differences in the phase and amplitude of the human circadian temperature rhythm: with an emphasis on morningness–eveningness

“…Several studies have shown that M‐type subjects have an earlier sleep schedule ( Horne and Ostberg 1976; Foret et al . 1982 , 1985; Mecacci and Zani 1983; Kerkhof 1991; Kerkhof and Lancel 1991; Carrier et al . 1997 ) and an earlier circadian temperature phase as measured by rectal temperature ( Kerkhof 1991; Lack and Bailey 1994; Kerkhof and Van Dongen 1996; Duffy et al .…”

Association of intrinsic circadian period with morningness–eveningness, usual wake time, and circadian phase.

“…One factor thought to contribute to interindividual differences in the timing of circadian rhythms is the preference for morning or evening activity patterns (Horne & Östberg, 1977). Although the timing of many physiological and behavioral rhythms are reported to differ between morning- and evening-type individuals (Bailey & Heitkemper, 1991; Foret, Touron, Benoit, & Bouard, 1985; Horne, Brass, & Pettitt, 1980; Horne & Östberg, 1976; Kerkhof, 1991; Kerkhof & van Dongen, 1996; Lack & Bailey, 1994; Lavie & Segal, 1989; Pátkai, 1971), many of those studies were confounded by the very differences in behavior used to define individuals as morning or evening types (Bailey & Heitkemper, 1991; Foret et al, 1985; Horne et al, 1980; Horne & Östberg, 1976; Kerkhof, 1991; Pátkai, 1971). For example, many studies did not collect data throughout the complete circadian cycle, limiting data collection to waking hours (Bailey & Heitkemper, 1991; Horne et al, 1980; Horne & Östberg, 1976; Pátkai, 1971), or they collected data from freely ambulatory individuals whose level or pattern of activity may have affected the physiological measures (Bailey & Heitkemper, 1991; Foret et al, 1985; Horne et al, 1980; Horne & Östberg, 1976; Kerkhof, 1991; Pátkai, 1971).…”