Effect of Continuous Heat Exposure on Sleep Stages in Humans

Libert, J. P.; Nisi, J. Di; Fukuda, Hideki; Muzet, Alain; Ehrhart, J; Amoros, Claire

doi:10.1093/sleep/11.2.195

Cited by 83 publications

(41 citation statements)

References 16 publications

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“…It is possible that thermal load is increased in summer, since increased wakefulness is a typical effect of heat-exposure conditions (Karacan et al 1978;Haskell et al 1981;Libert et al 1988). Wakefulness may be the only stage that can manage the increased thermal load, given that thermoregulation is less active during sleep than in wakefulness (Parmeggiani 1987).…”

Section: Discussionmentioning

confidence: 99%

Effects of season on sleep and skin temperature in the elderly

Okamoto-Mizuno

Tsuzuki

2009

Int J Biometeorol

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The effects of season on sleep and skin temperature (Tsk) in 19 healthy, elderly volunteers were investigated. Measurements were obtained in summer, winter, and fall, and activity levels were monitored using a wrist actigraph system for five consecutive days. The temperature and humidity of the bedrooms of the subjects' homes were measured continuously for five days. During actigraphic measurement, Tsk during sleep was measured for two nights. The bedroom temperature and humidity significantly increased in summer compared to winter and fall. In summer, the total sleep time decreased (mean +/- SE min; summer, 350.8 +/- 15.7; winter, 426.5 +/- 14.2; fall, 403.2 +/- 16.4) and wakefulness increased (P < 0.003) compared to those in fall or winter. The sleep efficiency index that was derived from wrist actigraphy was significantly decreased (P < 0.001) in summer (81.4 +/- 2.9%) compared with winter (91.6 +/- 1.3%) or fall (90.2 +/- 1.2%). The forehead Tsk significantly increased, while the chest and thigh Tsks were decreased in summer compared to those in fall or winter. These results suggest that, in the elderly, sleep is disturbed in summer more than in other seasons, and that this disturbance is related to fluctuations in Tsk.

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Section: Discussionmentioning

confidence: 99%

Effects of season on sleep and skin temperature in the elderly

Okamoto-Mizuno

Tsuzuki

2009

Int J Biometeorol

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“…The amount of REM sleep during summer remained almost at the basal level. The effect of acute exposure to warm ambient temperature on sleep has been studied extensively on human volunteers in controlled laboratory conditions (Karacan et al 1978;Muzet et al 1983;Libert et al 1988;OkamotoMizuno et al 1999;Okamoto-Mizuno et al 2004). These studies indicated that TST, stages 1 and 2, stages 3 and 4 and REM sleep decreased, with frequent and longer awakenings, greater shifting among sleep stages, and delayed onset of deep sleep (stages 3 and 4).…”

Section: Discussionmentioning

confidence: 99%

Changes in sleep patterns during prolonged stays in Antarctica

et al. 2008

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Various countries have permanent research bases in Antarctica that are manned year-round by a few members of an expedition team, facing extremes of temperature with the associated hardships. Acclimatisation to such an environment is associated with pyschophysiological changes along with alterations in sleep patterns. The present study was undertaken to explore the changes in sleep patterns of six members of the Indian expedition team during their winter stay at Maitri, the permanent research station of India in Antarctica. The mean (+/- SEM) age, height and weight of the subjects were 35.7 +/- 2.32 years, 168.3 +/- 2.37 cm and 71.0 +/- 1.88 kg, respectively. Polysomnographic sleep recordings were obtained as baseline data in November 2004 in Delhi (altitude 260 m, latitude 29 degrees N, longitude 77 degrees E); data on the same parameters were collected at Maitri, Antarctica (altitude 120 m, latitude 70 degrees 45' 39'' S, longitude 11 degrees 44' 49'' E) from January to December 2005. A one-way analysis of variance with repeated measures showed a significant variation with time (month effect) in most of the sleep parameters recorded. Total sleep time decreased from Delhi baseline values in all months, sleep efficiency decreased significantly during winter months, duration of waking period after sleep onset increased significantly in winter, sleep latency increased immediately after exposure in January, stages 3 and 4 (slow wave sleep) reduced during dark winter months, whereas stages 1 and 2 and rapid eye movement sleep increased during dark winter months. This study observed a prevailing general trend of sleep disturbances amongst overwintering members in a modern Antarctic station.

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“…INDIVIDUALS EXPOSED TO A THERMAL LOAD BEFORE 8,9,23,29,30,32,47 OR DURING 6,13,25,33,35,38,39,46 BED-TIME present alterations in their nocturnal sleep. Several adverse effects, which are known to reduce the subsequent vigilance level, have been determined, such as partial sleep deprivation and/or sleep fragmentation.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Nocturnal Environment Perceived as Warm on Subsequent Daytime Sleep in Humans

Dewasmes

Telliez

Muzet

2000

Sleep

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BED-TIME present alterations in their nocturnal sleep. Several adverse effects, which are known to reduce the subsequent vigilance level, have been determined, such as partial sleep deprivation and/or sleep fragmentation. Surprisingly, the influence of thermal stressors on subsequent daytime recovery sleep remains unknown, as only one such study has been made, 5 but it did not provide the magnitude of sleep changes. Moreover, the hypnic alterations provoked by thermal stressors may be enhanced by the unusual circadian placement and associated sleep deprivation.In the present study, we analyzed the daytime sleep patterns of individuals kept awake and exposed to a moderate warm stress during the preceding night. Because our interest was focused strictly on the influence of the thermal factor, we controlled the circadian placement and the duration of the diurnal sleep session, and thus also the sleepdeprived state of the volunteers participating in this study. MATERIALS AND METHODSSixteen young male subjects (20-25 years old) gave their informed consent to participate in the study, which had been approved by the local ethics committee. These volunteers were good sleepers, with sleeping habits intermediary between morning and evening types. 28 They had not been exposed and/or naturally adapted to a warm climate during the six months prior to the experiment.The subjects were randomly assigned to two equal independent groups (control and experimental) and were then studied in pairs. One pair was studied per week, with control pairs alternating with experimental pairs. Before starting the recordings, they were habituated to the experimental and sleep (00:00 -08:00) conditions for two successive nights and days. The habituation period was spent in a living room controlled in temperature. During the third night each subject went to an individual climatic (soundproof) chamber adjacent to the living room and was kept awake (23:00 -08:00). A light breakfast was served at 06:00 (<100kcal). Daytime sleep is usually shorter than nighttime sleep. In a previous experiment, thermally comparable to the present control condition, 10 subjects (also awake at night) slept ad lib (from 08:00) an average of 6.2hours (unpublished data). We thus limited the sleep duration in the present study to six hours (light switched off at 08:00). Throughout the experiment, subjects always slept partially Abstract: We studied the influence of a nocturnal environment perceived as warm on the subsequent daytime sleep of healthy human subjects (20-25 years old). From 00:00 to 8:00, they were kept awake and exposed to either a thermoneutral and comfortable (CN) or a warm and uncomfortable (EW) environment, as assessed by the predicted mean vote/percentage of persons dissatisfied questionnaire (PMV/PPD). The subjects then slept from 8:00 to 14:00 in a thermoneutral environment. Sleep was scored according to the Rechtschaffen and Kales criteria. Rectal temperature was recorded from 22:00 to the end of the sleep period. Compared to CN, a significant but mod...

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Effect of Continuous Heat Exposure on Sleep Stages in Humans

Cited by 83 publications

References 16 publications

Effects of season on sleep and skin temperature in the elderly

Effects of season on sleep and skin temperature in the elderly

Changes in sleep patterns during prolonged stays in Antarctica

Effects of a Nocturnal Environment Perceived as Warm on Subsequent Daytime Sleep in Humans

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