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The influence of room temperature on night sleep in man
Abstract
After preliminary experiments had determined that the night sleep (unclothed and uncovered) was subjectively undisturbed from 27 to 36°C, night sleep recordings were made on 10 healthy young men. 4 hrs before and after sleep, performance tests were made in constant room temperature. The subject slept at room temperatures of 27, 31 and 36°C in the climate chamber and were studied with polygraphic sleep recordings. The following results were obtained: The lower room temperature, the higher ther percentage of deep sleep and REM sleep was. Warm nights had higher percentages of wakefulness and higher latency of REM. Subjectively at 36°C no subject was 'refreshed', whereas 6 of the 8 students were 'refreshed' after sleeping at 27°C. Movements during sleep increased at higher temperatures and decreased at lower temperatures. This behavior is useful in terms of thermoregulation. Night sleep at 27°C leads to the greatest loss of body warmth (mean: 42 cal/m2), especially from the core of the body and increased of noradrenalin in the urine. The room temperature also excretion of the heart rate in all sleep stages. The minimal mean was found to be 52/min during the REM stage at 27°C. From the follow up observations, a carry over effect of the room temperature was noted in the morning. The excretions of 17 corticosteroids and total corticoids in the urine were decreased after the 36°C nights.
... A study in California found that setpoints found in Title 24 energy code compliance software (similar to those required for EnergyStar eligibility) overestimate the cooling setpoint and underestimate the heating setpoint (Woods, 2006). Similarly, the nighttime setup/setback default from EnergyStar does not reflect comfortable temperatures found in lab studies (Muzer, Libert, & Candas, 1984;Schmidt-Kessen & Kendel, 1973;Tsuzuki, Okamoto-Mizuno, Mizuno, & Iwaki, 2005). Yet these default temperatures found in programmable thermostats are used to determine energy savings in Title 24 compliance software programs (Woods, 2006). ...
... Several studies show better sleep at 26-27ºC (78.8-80.6ºF) compared to 31 or 36ºC (87.8 or 96.8ºF) (Schmidt-Kessen & Kendel, 1973). ...
Electrical utilities worldwide are exploring "demand response" programs to reduce electricity consumption during peak periods. Californian electrical utilities would like to pass the higher cost of peak demand to customers to offset costs, increase reliability, and reduce peak consumption. Variable pricing strategies require technology to communicate a dynamic price to customers and respond to that price. However, evidence from thermostat and energy display studies as well as research regarding energy-saving behaviors suggests that devices cannot effect residential demand response without the sanction and participation of people. This study developed several technologies to promote or enable residential demand response. First, along with a team of students and professors, I designed and tested the Demand Response Electrical Appliance Manager (DREAM). This wireless network of sensors, actuators, and controller with a user interface provides information to intelligently control a residential heating and cooling system and to inform people of their energy usage. We tested the system with computer simulation and in the laboratory and field. Secondly, as part of my contribution to the team, I evaluated machine-learning to predict a person's seasonal temperature preferences by analyzing existing data from office workers. The third part of the research involved developing an algorithm that generated temperature setpoints based on outdoor temperature. My study compared the simulated energy use using these setpoints to that using the setpoints of a programmable thermostat. Finally, I developed and tested a user interface for a thermostat and in-home energy display. This research tested the effects of both energy versus price information and the context of sponsorship on the behavior of subjects. I also surveyed subjects on the usefulness of various displays. The wireless network succeeded in providing detailed data to enable an intelligent controller and provide feedback to the users. The learning algorithm showed mixed results. The adaptive temperature setpoints saved energy in both annual and summertime simulations. The context in which I introduced the DREAM interface affected behavior, but the type of information displayed did not. The subjects responded that appliance-level feedback and tools that provided choices would be useful in a dynamic tariff environment.
... In contrast, nocturnal heat exposure causes very disturbed sleep. It has been found that humans sleeping in hot conditions exhibit a reduction in rapid eye movement sleep (REM), SWS, and marked increases in the number and duration of wakefulness episodes (5,6). ...
... The morning questionnaires, which examined subjective estimates of sleep quality, confirmed the EEG findings. Previous investigators have generally reported that heat induces an increase in the number of awakenings and the time spent awake and decreases in SWS and REM sleep (5,6,21,22). Our findings partly support these observations. ...
In a counter-balanced design, the effects of daytime and/or nighttime exposure to heat and/or traffic noise on night sleep were studied in eight healthy young men. During the day, the subjects were exposed to baseline condition (ambient temperature = 20 degrees C; no noise) or to both heat (35 degrees C) and noise. The duration of the daytime exposure was 8 h ending 5 h before sleep onset. The following nights, the subjects slept either in undisturbed (20 degrees C; no noise) or in noise, heat, or noise plus heat-disturbed environments. During the day, the various types of traffic noise were distributed at a rate of 48/h with peak intensities ranging between 79 and 86 dB(A). The background noise level was at 45 dB(A). At night, the peak intensities were reduced by 15 dB(A), the rate was diminished to 9/h, and the background noise was at 30 dB(A). Electrophysiological measures of sleep and esophageal and mean skin temperatures were continuously recorded. The results showed that both objective and subjective measures of sleep were more disturbed by heat than by noise. The thermal load had a larger impact on sleep quality than on sleep architecture. In the nocturnal hot condition, total sleep time decreased while duration of wakefulness, number of sleep stage changes, stage 1 episodes, number of awakenings, and transitions toward waking increased. An increase in the frequency of transient activation phases was also found in slow-wave sleep and in stage 2. In the nocturnal noise condition, only total number of sleep stage changes, changes to waking, and number of stage 1 episodes increased.(ABSTRACT TRUNCATED AT 250 WORDS)
... Further, increasing temperatures may strongly affect sleep because body thermoregulation is reduced during sleep (Carskadon et al. 2011;Heller et al. 1996), and a lower core body temperature is required for the onset and maintenance of sleep (Krauchi et al. 2000;van Someren et al. 2002). Many experimental human studies under laboratory conditions in the past 25 years have found that overly warm environments increase wakefulness and disturbance, and reduce sleep time (Bach et al. 2002;Haskell et al. 1981;Horne 1992;Lan et al. 2014;Schmidt-Kessen et al. 1973). Many epidemiological studies have also suggested that it may be the lack of nighttime relief from daytime heat that is particularly deleterious (e.g. ...
There has been little research into the thermal condition of the sleeping environment. Even less well documented and understood is how the sleeping thermal environment is affected by occupant behaviors such as the use of air-conditioning (AC) and electric fans, or window operations. In this paper we present results from a questionnaire survey administered to assess summertime bedroom thermal satisfaction and heat-coping strategies among New York City (NYC) residents. Specifically, we investigated current AC usage in bedrooms and examined alternate cooling strategies, cooling appliance usage patterns, and the motivations that drove these patterns during the 2015 summer.
Among survey respondents (n = 706), AC was the preferred heat-coping strategy, and for 30% of respondents was the only strategy used. Electric fan use and window opening were deemed ineffective for cooling by many respondents. Indeed, less than a quarter of all respondents ever opened windows to alleviate heat in their bedrooms. In general, people utilized strategies that modify the environment more than the individual person. Unsurprisingly, the frequency and overall use of AC were significantly associated with greater bedroom thermal satisfaction; however, setting AC to a lower temperature provided no additional benefit. In contrast, more frequent use of electric fans was associated with lower thermal satisfaction. In addition, 14.7% of all respondents did not have AC in their sleeping environment and 5.8% were without any AC at home. Despite the high penetration of AC ownership, usage cost was still a major concern for most.
This work contributes to a better understanding of bedtime heat-coping strategies, cooling appliance usage patterns, and associated thermal satisfaction in NYC. The findings of this study suggest resident AC usage patterns may not be optimized for thermal satisfaction. Potential alternative cooling approaches could be explored to better balance maximizing thermal comfort while reducing energy consumption and environmental impact.
... Candas et al. demonstrated that REM sleep more disturbed by the thermal transients than SWS. It was also in agreement with many studies [11]. From this, the fact that REM sleep share rate decreased suggests that REM sleep was disturbed by in-bed temperature control at 32 o C. ...
It is important to create a comfortable environment to restful sleep. In this study, we trial-produced an in-bed temperature control system. At first, we statically controlled the temperature in the subject's bed at 32°C by using the system, and examined how this control affected sleep. We were able to confirm that the ratio of slow-wave sleep (SWS) increased in comparison to cases in which the temperature in the bed was not controlled. Next, the temperature in the subject's bed was dynamically controlled at temperature change patterns according to sleep cycles that is as follows; Heating during the REM sleep period and cooling during the SWS sleep period were conducted n the range of 32±2°C, and the case of the opposite phase. The result showed that cooling during the REM period increased the REM sleep share rate. Based on these results, an increase of the REM sleep share rate at around 30°C could be confirmed, indicating a possibility that the REM period thermoneutrality zone shifted to a lower temperature, compared with that of SWS.
... On the contrary, heat exposure during the night leads to sleep disruption. Sleeping overnight in hot chambers at ambient temperatures (dry bulb temperature, Tdb) between 31 and 38°C reduces both SWS and REM sleep [8] or solely REM sleep [9] with frequent sleep interruptions [10]. Exposure to 36°C for 5 days and nights in a climatic facility [11] led to a decrease in SWS, compared to a similar 5-day exposure to 19°C. ...
Human sleep is sensitive to the individual's environment. The present review examines current knowledge of human sleep patterns under different environments: heat exposure, cold exposure, altitude, high pressure and microgravity in space. Heat exposure has two effects. In people living in temperate conditions, moderate heat loads (hot bath, sauna) prior to sleep provoke a delayed reaction across time (diachronic reaction) whereby slow-wave sleep (SWS) augments in the following night (neurogenic adaptive pathway). Melanoids and Caucasians living in the Sahel dry tropical climate experience diachronic increases in SWS throughout seasonal acclimatization. Such increases are greater during the hot season, being further enhanced after daytime exercise. On the contrary, when subjects are acutely exposed to heat, diachronic decreases in total sleep time and SWS occur, being often accompanied by synchronic (concomitant) diminution in REM sleep. Stress hormones increase. Nocturnal cold exposure provokes a synchronic decrease in REM sleep along with an activation of stress hormones (synchronic somatic reaction). SWS remains undisturbed as it still occurs at the beginning of the night before nocturnal body cooling. Altitude and high pressure are deleterious to sleep, especially in non-acclimatized individuals. In their controlled environment, astronauts can sleep well in microgravity. Exercise-induced sleep changes help to understand environmental effects on sleep: well-tolerated environmental strains may improve sleep through a neurogenic adaptive pathway; when this "central" adaptive pathway is overloaded or bypassed, diachronic and synchronic sleep disruptions occur.
This study aimed to clarify the body heat balance between the human body and its sleep environment. However, because heat transfer coefficients of sleeping positions have not been sufficiently studied, body heat balance of its positions cannot be accurately assessed. Therefore, the purpose of this paper is to propose the radiative heat transfer coefficient of the whole body and the empirical formula of convective heat transfer coefficient of the whole body in natural convection, with focus on the convective heat transfer area of the human body. Measurements were carried out with a thermal mannequin. Experimental posture was supine (floor contact) position. Thermal sensors directly measuring the heat flux and thermal radiation were employed. Experiments were conducted under the following conditions in an artificial climate chamber. Air temperature was set to six cases (ta=16, 18, 20, 22, 24, 26℃). Wall, floor and ceiling temperatures were set to equal air temperature (mrt=ta). Relative humidity and air velocity were kept constant level of 50% and less than 0.2m/s. The following results were obtained. The radiative heat transfer coefficient with supine (floor contact) posture was 3.235W/(m^2・K). The empirical formula of the convective heat transfer coefficient of the whole body with supine (floor contact) posture was represented hc=0.881ΔT^<0.368>[W/(m^2・K)] where the power of the difference between the mean skin temperature corrected by convective heat transfer area and air temperature (ΔT[K]).
When the Nobel Prize in Physiology/Medicine was awareded in 2017 to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young, the new era of chronobiology and medicine has deserved the world’s attentions, as every living organism on Earth seems to be controlled. Rhythmicity of physiological parameters is found in virtually all living systems. The circadian rhythm with its most obvious expression, the sleep–wake cycle, is closely tied to the diurnal rhythm of day and night. A disturbance of this highly regulated system can lead to circadian misalignment resulting in sleeping difficulties with consequences on many physiological functions like psychological and physical performance, the metabolism, and the immune system as it could be found in night shift workers or in people suffering from chronic jet lag. Stress in its many forms, generally perceived as an excessive demand on human psychological and/or physiological adaptive capabilities, can have a direct influence on the human sleeping pattern due to the integration of neuronal and hormonal pathways of the stress reaction and the circadian regulation. Thus excessive and/or chronic stress can lead to a disturbance of the circadian rhythm as it can be found in diseases like depression and posttraumatic stress disorder. Extreme environments such as high altitude, hot or cold environments, or microgravity also can alter human sleep patterns as well as during isolation and confinement—experimental setups that serve to simulate the isolated nature of long-term space travel.
Contexte : Le trafic aérien, en constante augmentation au cours de ces dernières décennies, n'est pas sans impact sur l'environnement et la population. En particulier, le bruit émis par les avions constitue une nuisance importante et un problème majeur de santé publique, notamment en termes de perturbations du sommeil. Pour autant, en France surtout, les conséquences de l'exposition au bruit des avions restent insuffisamment évaluées. Objectif : L'objectif de ce travail de thèse est de mieux connaître et de mieux quantifier les effets du bruit des avions sur la qualité du sommeil des riverains des aéroports en France, en distinguant qualité subjective et qualité objective. Méthodes : Pour répondre aux objectifs de cette thèse, nous avons utilisé les données recueillies dans un programme de recherche épidémiologique appelé DEBATS (Discussion sur les Effets du Bruit des Aéronefs Touchant la Santé). L'étude principale, dite « étude longitudinale », a inclus 1244 participants vivant à proximité de trois aéroports français d'importance : Paris-Charles de Gaulle, Lyon-Saint Exupéry et Toulouse-Blagnac. La qualité subjective du sommeil a été évaluée grâce à un questionnaire administré par des enquêteurs au domicile des sujets. Le niveau d'exposition au bruit des avions a été estimé à l'adresse du domicile de chaque participant à partir des cartes de bruit produites par la Direction Générale de l'Aviation Civile. Une étude complémentaire dite « étude sommeil » a permis d'évaluer la qualité objective du sommeil de 112 des 1244 participants à l'étude longitudinale grâce au port d'un actimètre pendant huit jours et d'un Actiheart (enregistreur de la fréquence cardiaque) pendant une nuit. Des mesures acoustiques ont été réalisées pendant ces huit jours en façade et à l'intérieur de la chambre à coucher des participants, afin de caractériser leur exposition au bruit des avions à l'aide d'indicateurs non seulement énergétiques (LAeq, LA90) mais aussi événementiels (nombre d'événements et niveau maximum de bruit de l'évènement ou LAmax). Résultats : L'analyse de « l'étude longitudinale » a permis de montrer une association entre l'exposition au bruit des avions la nuit (Lnight) et la qualité subjective du sommeil caractérisée par un risque de déclarer dormir moins de 6 heures par nuit (OR=1,63 pour 10 dB(A) ; IC 95% : 1,15-2,32) et de se sentir fatigué au réveil (OR=1,23 pour 10 dB(A) ; IC 95% : 1,00-1,54). Nous n'avons pas trouvé de relation significative avec les autres paramètres subjectifs de la qualité du sommeil rapportés par les sujets eux-mêmes, tels que le temps d'endormissement, les éveils nocturnes, la satisfaction du sommeil et la prise de médicaments pour dormir. Nous avons également montré une association entre l'exposition au bruit des avions et les paramètres objectifs de la qualité du sommeil avec une augmentation du temps d'endormissement et de la durée des éveils intra-sommeil, une diminution de l'efficacité du sommeil, mais aussi une augmentation du temps total de sommeil et du temps passé au lit (cette dernière pouvant être interprétée comme un mécanisme d'adaptation à la privation de sommeil). Les indicateurs énergétiques, mais plus encore les indicateurs liés aux événements de bruit, sont significativement associés aux paramètres objectifs de la qualité du sommeil. Par exemple, les événements de bruit d'avions détectés à l'intérieur de la chambre à coucher sont associés à une augmentation de la durée totale des éveils intra-sommeil supérieure à 30 minutes (OR=1,10 pour 10 événements ; IC 95% : 1,03-1,16). Enfin, nous avons observé une augmentation significative de l'amplitude de la fréquence cardiaque pendant un évènement sonore associé au passage d'un avion et le niveau maximum de bruit de cet évènement (LAmax) [etc...]
In the last few decades, there has been a decline in average sleep duration and quality that has adversely affected general health of the population. Increased use of artificial lighting, television, noise, and light emitting gadgets in the post-industrial society has led to an environment full of factors that can adversely affect sleep. Sleep is essential for the restoration of health and well-being, and has a direct effect on the quality of life of an individual. It is thus imperative to design constructions that provide a sleep permissive environment. In addition to environmental factors, sleep and wakefulness in humans is affected by a multitude of physiological parameters as well. The mechanisms and interplay between these factors that influence sleep permissiveness or promotion have received relatively little attention. The present review takes a holistic approach in explaining the basic circadian and homeostatic processes that influence sleep and sleepiness, and then delves deeper into how the thermal rhythms of the body affect these processes. It also discusses previous research and models in construction design that influence ambient temperature, skin surface temperature, and other thermoregulatory factors that can be controlled for optimal sleep.
Fast alle Lebewesen und so auch der Mensch zeigen rhythmische Veränderungen verschiedenster physiologischer Variablen. Der zirkadiane Rhythmus, also die Tagesrhythmik, wird hauptsächlich beeinflusst durch die äußere Einwirkung des Wechsels von Tag und Nacht. Dieser Rhythmus wird in Zentren des Hypothalamus generiert und beeinflusst seinerseits alle peripheren Zellen. Schlaf als aktiver Erholungsprozess und notwendige Voraussetzung für höhere Leistungen des ZNS wie Gedächtnis und Abstraktion wird initiiert entsprechend des Zusammenspiels der Regulatoren dieses zirkadianen Rhythmus. Eine Störung der Regulation, z. B. durch eine Verschiebung der inneren Uhr und der äußeren Einflüsse wie beim Jetlag kann zu Schlafstörungen und zu negativen Folgen für weitere Körperfunktionen führen. Verschiedene Umgebungseinwirkungen wie Stress, Hitze, Kälte etc. nehmen Einfluss auf den zirkadianen Rhythmus. Dieser wiederum ist eng verknüpft mit der Thermoregulation, dem Stoffwechsel, der Fibrinolyse und den Immunfunktionen.
Mit vielen Argumenten ist es zu rechtfertigen, daß ein Psychiater auf dem Internisten-Kongreß zum Thema „Störungen der Schlaf-Wach-Funktion“ zu Wort kommt. Lassen Sie mich bitte einleitend 6 soldier Argumente aufzählen:
1.
Die neurobiologische Grundlagenforschung in der Psychiatrie — insbesondere die biochemische Forschung auf dem Depressionsgebiet — konvergiert hinsichtlich der Untersuchungsgegenstände und der Methoden in immer gräßerem Maße mit der in den zurückliegenden zwei Jahrzehnten so erfolgreichen Erforschung der zentralen Schlaf-Wach-Regulation. So stehen z. B. biogene Monoamine wie Serotonin und Noradrenalin und deren Präkursoren ganz im Mittelpunkt des Interesses nicht nur der neurobiologischen Depressions-Forschung [43, 27]; Untersuchungen des Stoffwechsels, der Wirkungsweise, der Angriffsorte dieser zentralen Neurotransmitter sind ebenso auch ein Brennpunkt der modernen Schlafforschung [24, 11, 30]. Das gleiche gilt — um auch auf ein Beispiel aus der klinischen Neurophysiologie hinzuweisen — für die Erforschung der Bedeutung des sog. REM-Schlafs, der nicht nur als Konstituens des physiologischen Schlafs zu gelten hat, sondern dessen Störungen und Abwandlungen auch für das depressiven Verstimmungen zugrunde liegende pathophysiologische Geschehen bedeutungsvoll sind [25, 44].
Rhythmicity of physiological parameters is found in virtually all living systems. The circadian rhythm with its most obvious expression, the sleep-wake cycle, is closely tied to the diurnal rhythm of day and night. A disturbance of this highly regulated system can lead to circadian misalignment resulting in sleeping difficulties with consequences on many physiological functions like psychological and physical performance, the metabolism, and the immune system as it could be found in night shift workers or in people suffering from chronic jet lag. Stress in its many forms, generally perceived as an excessive demand on human psychological and/or physiological adaptive capabilities, can have a direct influence on the human sleeping pattern due to the integration of neuronal and hormonal pathways of the stress reaction and the circadian regulation. Thus excessive and/or chronic stress can lead to a disturbance of the circadian rhythm as it can be found in diseases like depression and posttraumatic stress disorder. Extreme environments such as high altitude, hot or cold environments, or microgravity also can alter human sleep patterns as well as during isolation and confinement - experimental setups that serve to simulate the isolated nature of long-term space travel. © 2012 Springer-Verlag Berlin Heidelberg. All rights are reserved.
one manner in which the neurophysiological and neuropharmacological substrates of rapid-eye-movement (REM) sleep have been studied has been to use a decrease in REM sleep as an index of whether a specific treatment directly affects it. The concept behind this approach is simple and appealing: if an area of the brain is damaged, or if a brain neurotransmitter system is blocked, and REM sleep decreases, then that area of the brain or that neurotransmitter system must be involved in generating or maintaining REM sleep. However, there is an error in this reasoning: one cannot determine much about the function of a particular part of the brain or a particular neurotransmitter system if the behavior under observation disappears or is diminished after the manipulation.
Sleep must be protected against aggressions and manipulations, made voluntarily or not, which tend to reduce its duration to the benefit of prolonged waking state. Sleep disturbances have various origins but only external factors of our environment, such as noise and extreme thermal ambient conditions, will be considered here. These disturbance factors generally lead to increasing the waking time and time spent in shallow sleep stages and to reducing time spent in slow wave sleep and REM-sleep. The consequences of these disturbances are mainly seen during the consecutive waking period. The sensation of fatigue due to the lack of sleep and the associated low vigilance level, together with the deterioration of mood and performance, modify the person's attitudes and in some cases can lead to serious consequences in terms of accident risks.
1.1.|The thermal response to heating and cooling transients was compared in man, during slow-wave sleep (SWS) and during rapid-eye-movement (REM) sleep.2.2.|Results showed that decreases in air temperature affected these sleep stages more frequently than did the air temperature increases and that stage changes that occurred during thermal stimulation were more frequent in REM sleep than in SWS.3.3.|Thermosensitivity was maintained during SWS as well as during REM sleep.
1.
Polygraphic night sleep recordings in eight healthy male volunteers with simultaneous measurement of rectal temperature, plasma growth hormone (HGH), cortisol, and TSH concentrations were performed during normal, raised, and lowered ambient and body temperature.
2.
There was a statistically significant increase in plasma cortisol and TSH levels during cold nights with a smaller rise during high temperatures.
3.
Growth hormone levels, measured as the mean highest plasma concentration in the first two NREM-REM sleep cycles, were slightly lower during hot and cold nights than corresponding baseline values. It is suggested that there may be an inverse relation between ACTH and HGH secretion by the anterior pituitary gland.
4.
During the nights of high ambient temperature, decreased total duration of sleep and particularly low values of paradoxical sleep were observed. Night sleep in low ambient temperature with a significant decrease of body temperature is not different from baseline conditions.
5.
The results suggest that a pronounced increase in stress hormone secretion may occur without changes in polygraphic EEG criteria.
The aim of the study was to investigate the effect of ambient temperature on sleep, sleep apnea, and morning alertness in patients with obstructive sleep apnea.
Randomized controlled trial.
In-hospital investigations.
Forty patients with obstructive sleep apnea naïve to treatment, with an apnea-hypopnea index of 10-30.
Three different nights in room temperatures of 16°C, 20°C, and 24°C.
Overnight polysomnography and Karolinska Sleepiness Scale.
The obstructive apnea-hypopnea index was 30 ± 17 at 16°C room temperature, 28 ± 17 at 20°C, and 24 ± 18 at 24°C. The obstructive apnea-hypopnea index was higher at 16°C room temperature versus 24°C (P = 0.001) and at 20°C room temperature versus 24°C (P = 0.033). Total sleep time was a mean of 30 min longer (P = 0.009), mean sleep efficiency was higher (77 ± 11% versus 71 ± 13% respectively, P = 0.012), and the patients were significantly more alert according to the Karolinska Sleepiness Scale (P < 0.028) in the morning at 16°C room temperature versus 24°C. The amount of sleep in different sleep stages was not affected by room temperature.
Untreated patients with obstructive sleep apnea sleep longer, have better sleep efficiency, and are more alert in the morning after a night's sleep at 16°C room temperature compared with 24°C, but obstructive sleep apnea is more severe at 16°C and 20°C compared with 24°C.
This study is registered in ClinicalTrials.gov number NCT00544752.
1.1. The study aimed at knowing how differently two kinds of room temperature could influence the core temperature during 8 h night sleep and subjective sleep sensation.2.2. Two kinds of room temperature used were (i) an increase from 27°C to 28.5°C over 4 h after the subjects went to bed and then a decrease from 28.5°C to 27°C over 4 h (Rise-Fall); (ii) a decrease from 27°C to 25.5°C over 4 h and then an increase from 25.5°C to 27°C over 4 h (Fall-Rise).3.3. Core temperature fell more deeply in Fall-Rise.4.4. Minimum value of core temperature was observed ca. 6 h later in Fall-Rise after the subjects retired, while it was not consistent in Rise-Fall.5.5. Subjective sleep sensation was better in Fall-Rise.
Studies on the interaction between sleep and thermoregulation are reviewed with regard to the processes underlying the ultradian evolution of behavioral states. The experimental evidence shows that thermoregulatory mechanisms influence the waking-sleeping cycle in both the absence or the presence of a thermal load. Such a control appears to be a functional necessity to maintain physiological homeostasis.
Six male subjects slept nude except for shorts on a bed made from nylon webbing at 5 different ambient temperatures (TaS): 21, 24, 29 (thermoneutrality), 34 and 37 degrees C. Standard electrophysiological recordings were obtained and analyzed for sleep stages. Temperature displayed a significant quadratic trends for nearly every sleep variable, such that TaS above or below thermoneutrality had similar effects on sleep patterns. Multiple comparisons showed that 21 degrees C was the most disruptive condition, and that cold TaS were generally more disruptive to sleep than warm TaS. There were marked individual differences in sensitivity of sleep to cold. Decreases in REM sleep in humans produced by heat or cold probably result from a general disruption of sleep processes rather than being specifically related to the status of the thermoregulatory system during REM sleep.
The sleep-waking cycle was studied in two strains of mice during continuous exposure over 3 weeks to an ambient temperature of 34 degrees C or 10 degrees C. As compared to the 25 degrees C control period, C57BL/6 mice showed at 34 degrees C a mean increase of 25% in slow-wave sleep (SWS) particularly during the night. Paradoxical sleep (PS) was also increased by 58% during the exposure period particularly during the night and this resulted from an increase in the number of PS episodes. At 10 degrees C SWS was decreased by 9% only during the first week of exposure, whereas PS was reduced by 24% throughout due to a decrease in the number of PS episodes, although their duration increased. The acrophase of the circadian rhythms was not affected by the changes in ambient temperature. In the BALB/c strain at 34 degrees C SWS and PS were increased only during the first week by 13% and 77%, respectively. At 10 degrees C SWS was decreased by 7% throughout and PS was decreased by 36% due to a reduction in the number of PS phases during the light period. On returning to 25 degrees C, a rebound in PS confirmed the PS deprivation in the cold in both strains.
Five young adult males slept two consecutive nights under each of the five ambient temperatures chosen within the usual range: 13 degrees C, 16 degrees C, 19 degrees C, 22 degrees C, and 25 degrees C. Bedding and other ambient parameters were kept constant under all five ambient temperature conditions. The average REM cycle length significantly decreased when the ambient temperature increased from 13 degrees C to 25 degrees C. Other REM sleep characteristics such as total duration of REM sleep, average REM period, and REM sleep latency did not significantly differ from one ambient temperature condition to another.
The frequency of body movement in the elderly and young people during sleep was measured in order to investigate the effect of hot thermal environments on sleep in summer. Simultaneously, room temperature and humidity were also measured. In the morning after measuring body movements, the subjects completed a questionnaire about their night's sleep. The results obtained were as follows: 1) The time of going to bed and rising in the elderly was significantly earlier than the young. 2) The elderly had a tendency to judge their sleep as "good", however, there were no significant differences between the two groups. 3) The room temperature for the elderly during sleep ranged from 25 to 28 degrees C (mean 26.5 degrees C). On the other hand, it was between 20 and 30 degrees C (mean 27.1 degrees C) in the young, which was significantly higher than that of the elderly. 4) Body movement in the elderly during sleep was significantly greater than those in the young. 5) A significant relation between body movement and room temperature was found within each group. Under conditions of less than 28 degrees C of room temperature, there were significantly higher rates of body movement in the elderly.
This study examined the effects of continuous heat exposure on sleep structure during a partial sleep-deprivation regime. The experimental protocol was divided into three periods. After a baseline period (5 days and nights at 20 degrees C), the sleep of the subjects was restricted to the second half of the night (3 a.m.-7 a.m.) for four consecutive nights. The restricted-sleep period was followed by two recovery days and nights. During the deprivation and recovery periods, the ambient temperature was 20 degrees C for six of the 12 subjects and 35 degrees C for the others. Sleep, esophageal and mean skin temperatures were continuously recorded. At 20 degrees C, the expected effect of sleep debt was apparent. There were significant reductions in time spent awake and in latencies for sleep and stage 4 sleep. The duration of stage 4 sleep significantly increased during the four successive restricted-sleep nights, whereas esophageal temperature significantly decreased over the successive days. When heat was added, esophageal temperature decrease was weakened, and the significant increase in stage 4 duration seen at 20 degrees C was not found. The findings suggest that the heat load imposed in our experimental condition has a suppressive effect on sleep stage 4 increase, which is induced by sleep restriction. The hypothesis that an increase in this sleep stage serves as a mechanism for energy conservation should be also considered.
We have conducted the first study of sleep in the platypus Ornithorhynchus anatinus. Periods of quiet sleep, characterized by raised arousal thresholds, elevated electroencephalogram amplitude and motor and autonomic quiescence, occupied 6-8 h/day. The platypus also had rapid eye movement sleep as defined by atonia with rapid eye movements, twitching and the electrocardiogram pattern of rapid eye movement. However, this state occurred while the electroencephalogram was moderate or high in voltage, as in non-rapid eye movement sleep in adult and marsupial mammals. This suggests that the low-voltage electroencephalogram is a more recently evolved feature of mammalian rapid eye movement sleep. Rapid eye movement sleep occupied 5.8-8 h/day in the platypus, more than in any other animal. Our findings indicate that rapid eye movement sleep may have been present in large amounts in the first mammals and suggest that it may have evolved in pre-mammalian reptiles.
1. In a moderately sweating condition pressure upon one side of the body evokes without exception a hemihidrosis of the opposite side.2. In similar conditions, pressure upon the soles or hip evokes the upper and lower sweating reflex.3. Pressure on one side of the body does influence sweating from mental origin.
Total urinary excretion of adrenaline, noradrenaline and of 3-methoxy-4-hydroxymandelic acid in normal and in hypertensive persons was determined. The results were compared with those obtained in pheochromocytoma cases.
The catecholamines were isolated by column chromatography on alumina and estimated fluorimetrically after conversion into trihydroxyindol derivatives. After thorough investigations of the procedure the total amount of catecholamines excreted in 41 normal subjects was determinend. 9 patients with nephrogenic and vascular hypertension ware also considered normal, as in these cases the catecholamine metabolism is not altered and other humoral and/or mechanical factors are responsible for the elevated blood pressure. Values obtained in this normal contingent ranged from 25–157 µg/day with an average of 69.4 µg/day and a standard deviation of ±28.2 These results are in close agreement with values obtained by other authors using similar and more recent methods.
In comparison to normal subjects the investigated 77 cases of essential hypertension revealed a tendency towards an increased excretion of catecholamines, this beeing particularely the case in paroxysmal hypertension. Statistically, however, there has been no significant difference between the values obtained in normal persons and those found in hypertension (mean values 74.2 µg/day;t-test 0.4>P>0.3). Comparison of normal values and values of paroxysmal hypertentension was also insignificant (t-test 0.2>P>0.1). These results appear to disagree somewhat with the findings of v.Euler [28], v.Studnitz [85] and others who observed an increased catecholamine and 3-methoxy-4-hydroxymandelic acid excretion in hypertensive subjects. Probably the increase of catecholamine excretion in our hypertensive material would show more clearly if all of the probands had been under standard conditions. The highest single values were found in permanent hypertension, whereas the group of patients with paroxysmal hypertension (14 cases) showed the highest mean value (81.7 µg/day).
3-methoxy-4-hydroxymandelic acid was coupled with diazotized p-nitroanilin and the purple staining complex was determined spectrophotometrically after extraction with chloroform-n-butanol.
In summary one can state that the simultaneous estimation of catecholamines and of 3-methoxy-4-hydroxymandelic acid gives a distinct parameter in diagnosis and differential diagnosis of pheochromocytoma.
1.
A new method of EEG interval spectrum analysis (EISA) is described. It is based on the development of an earlier interval analysis, proposed 1958/1961. In contrast to Fourier's analysis, only larger waves of more than a third of the average amplitude are selected and their interval is measured automatically. Each reciprocal value of these intervals, corresponding to frequencies of 1–30 per sec, is marked by a single point of the ordinate scale with slow paper speed (2.5–20 mm per minute). This allows a compression of long EEG spectral records on a very short time scale. In contrast to earlier frequency analyses which average certain frequency bands, the EISA apparatus records single EEG wave intervals continuously and aperiodically.
2.
The EISA method is suitable for long duration recordings of EEGs over several hours. A night sleep EEG of 8 hours is condensed for synopsis on a record of 1.2 m length. The advantages and limits of the method in comparison to other automatic EEG analysers are discussed.
3.
The practical application of the method is demonstrated by EEG recordings of night sleep and during anesthesia, partly with telemetry. The slowing and disappearance of alpha rhythms at the onset of sleep and the slow waves of deep sleep and anesthesia are clearly indicated in the synoptic EISA record. The different EEG stages of sleep are well distinguishable and their durations can be measured easily from the EISA record. Especially the paradoxical stage with rapid eye movements (REM sleep) stands out distinctly and shows different features from an arousal EEG and other sleep stages.
EEG, EOG, ECG and other physiological functions were continually recorded with healthy, sleeping subjects before, during and after an experimental increase of the ambient temperature (¯t
max=39 ‡C). The ascertained differences and the comparison with the data gained from the controls were tested by means of parametric and non-parametric methods. Among others, the following effects of the rising ambient temperature were significant:1.
increase in the heart rate and its variability,
2.
rise in the number and duration of changes in the body position,
3.
tendency towards a greater variability of the rectal temperature,
4.
changes in the frequency distribution of the EEG-activity patterns and
5.
reduction of sleep depth or interruption of sleep according to quantiative EEG-criteria.
Extent and course of the observed changes in the ascertained values give rise to the conclusion that a disturbance of sleep coordination, occur with increasing ambient temperature, already prior to the waking up due to the changed temperature.
Catheterized urology patients were shown to have increases in urinary 17-hydroxycorticoids regularly associated with REMS epochs when they were studied electrophysiologically all night, with their urinary catheter output connected to a volume driven fraction collector.
1.All experiments were carried out on unrestrained cats with chronically implanted electrodes.2.The sleep wakefulness pattern was studied over ten day periods. After five days the carotid sinus nerves were cut bilaterally. After the denervation the total duration of sleep and wakefulness remained unchanged. The only difference which could be observed was an increase of the number of short-lasting phases of wakefulness occurring during synchronized sleep.3.If the carotid sinus and depressor nerves were cut, the total duration of synchronized sleep was significantly diminished.4.Short-lasting rises of blood pressure were produced by an occlusion of the thoracic aorta or by strong rapid injections of saline. These mechanically produced elevations of blood pressure were immediately followed by an arousal.5.If the blood pressure was raised over a period of one or two hours by vasopressin, a marked increase of the number and the total duration of wakefulness was observed.6.A fall in blood pressure was produced by stimulation of the peripheral stump of the vagus. If the stimulus was applied during relaxed wakefulness, EEG synchronisation with behavioral signs of sleep occurred simultaneously with the fall in blood pressure.7.It can be concluded that the monotonous synchronous inflow from the baroreceptors is at least in part responsible for the onset and maintenance of synchronized sleep.8.The hypothesis is put forward that two feed backs, one through the baro-receptor discharge and another one through the blood pressure, are influencing the regulation of sleep and wakefulness.
During 7 hours of comfortably warm sleep, average metabolic rates of 11 Indian and 7 white men were alike. Since the Indians were 15% lighter their metabolic rates (MR's) referred to weight were greater. During a night at 0° with insufficient covering, MR's rose to 129% and 132% in the two groups. Cold caused equal myographic records of shivering (15% and 13% of records) and gross muscular movement appeared in 6.5% of the records for each group. Encephalograms showed that Indians slept more (51%) than whites (31%). Shivering was recorded in Indians and white men during encephalographic indications of sleep. Rectal temperatures of Indians declined about 0.5°. During cold nights skin on the bodies of all subjects cooled 3°–5° and about 15° on the feet. All subjects were disagreeably cold, but their cold sensations stimulated metabolic heat production only half as much as would be necessary to maintain fairly comfortable warmth.
Submitted on August 3, 1959
A method is presented for the determination of serotonin using a spectrophotofluorimeter. The method is suitable for platelet rich plasma and isolated platelet suspension. Serotonin is extracted from a protein free filtrate and the fluorescence measured in hydrochloric acid. Platelet rich plasma serotonin levels have been determined in 28 subjects.
Metabolic and thermal studies were conducted at night at Pangnirtung, N.W.T., on a group of ten Eskimo hunters from Cumberland Sound, Baffin Island, and on three white controls, to compare their reactions to cold (5 ± 1 C) with that of other racial groups. Cumberland Sound Eskimos maintained a resting metabolism that was elevated, according to DuBois standards, during sleep on warm nights. This elevation was not found in hospitalized men who had been living for an average of 6 months in Edmonton, Alberta. During exposure to moderate cold, the Cumberland Sound Eskimos and white controls had an elevated metabolism, shivering, and a disturbed sleep. Peripheral temperatures were maintained at a higher level in Eskimos than in whites. Because of the absence of marked physiological differences between Eskimos and whites, it is concluded that the principal adaptation of these Eskimos to their climate is technological.
Submitted on June 4, 1962
The acute exposure of dogs to an environmental temperature of 0 C evoked an elevation in plasma cortisol concentration which was apparent within 15 min and persisted for the 45 min of exposure. Gradual cooling of the environment over a 45-min period to a minimal temperature of 0 C failed to elevate plasma cortisol concentrations, although other compensatory mechanisms such as cutaneous vasoconstriction were active. Acute lowering of preoptic temperature also evoked a rise in plasma cortisol concentrations associated with lowering of pinna and elevation of rectal temperature. In this case the response was transient; plasma cortisol levels began to fall after 15 min of cooling even though cutaneous vasoconstriction was maintained. The results are interpreted to mean that acute lowering of environmental or preoptic temperature can activate the pituitary-adrenal system.
This chapter discusses an investigative study conducted to establish certain objective correlates of refreshing and unrefreshing sleep. Two groups consisting of 11 emotionally stable, and 11 emotionally labile subjects were selected from a larger sample of 127 randomly selected male students. Differentiation of these two study groups was made by a measure of emotional stability-lability established through factorial analyses of questionnaire data, body measurements, and measures of autonomic functions. In the investigation, average depth of sleep as evidenced by electroencephalogram (EEG)criteria failed to differentiate the two study groups. Findings of the present study, however, indicated that emotionally labile subjects manifest more movements of facial muscles during sleep, and as shown by actographic recordings, they display less body movements and less pronounced body movements during sleep than emotionally stable subjects. Multiple correlations of these indices with the questionnaire-scale utilized to assess subjective feelings of freshness following sleep yielded a highly significant coefficient of 0.80. Based on the results, objective correlates of sleep subjectively reported to be refreshing consist of minimal movements in facial muscles and a maximum of pronounced body movements during sleep. As measured by EEG potentials, depth of sleep appeared to be unrelated to the degree of freshness on waking.