• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.7
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• pp.535-540
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• 2006

This study was performed In evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of Physiological signals under variations in thermal conditions. Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. It was checked whether they had a good sleep before the night of experiment. EEGs were obtained from C3-A2 and C4-A1 electrode sites and EOGs were acquired from LOC (left outer canthus) and ROC (right outer canthus) for REM sleep detection. Sleep stages were classified, then TST (total sleep time), SWS (slow wave sleep) latency and SWS/TST were calculated for the evaluation of sleep efficiencies on thermal conditions. TST was defined as an amount of time from sleep stage 1 to wakeup. SWS latency was from light off time to sleep stage 3 and percentage of SWS over TST was calculated for the evaluation of sleep quality and comfort sleep under thermal conditions. As result, the condition which raise a room temperature provided comfortable sleep.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.1-6
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• 2006

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of EEGs and MST under four thermals conditions. Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber of $4.1\times4.9\times2.7m$ size. EEGs were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then TST, SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, it was concluded that indoor thermal environments of $24\~26^{\circ}C$ was the best for comfortable and deep sleep.

• Journal of Life Science
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• v.12 no.4
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• pp.375-382
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• 2002

The purpose of this experiment was to examine influence of acute exercise on nocturnal sleep which had been disrupted by caffeine(400mg$\times$3) thought the daytime. Six healthy young males aged 21.0$\times$0.2 yr with a history of low caffeine use. Subjects completed three conditions in a within-subject. At three conditions Sleep EEG were investigated: (1) nocturnal following quiet rest, (2) nocturnal sleep following the consumption of 1200mg of caffeine (3) nocturnal sleep following cycling at 60 min of 60% V $O_{2peak}$ with 1200mg of caffeine consumption. Sleep data were calculated for REM sleep, REM latency, sleep onset latency, sleep efficiency, sleep stages, SWS. Those data were analyzed using repeated-measures ANOVA of change scores. A main effect to, drug(caffeine) indicated that caffeine elicited sleep disturbance that is, TST and sleep onset latency increase and sleep efficiency and stage 4 decrease. The effects of exercise on sleep following caffeine intake generally improve sleep that is, stage 2, 3 and SWS increase and sleep onset latency decrease. A condition effect for sleep indicated sleep improvement after exercise Therefore The data supported a restorative theory of slow-wave sleep and suggest that acute exercise may be useful in promoting sleep and reducing sleep disturbance elevated by a high dose of caffeine.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.307-312
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• 2007

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of sleep efficiency and MST under four thermals conditions ($22^{\circ}C,\;24^{\circ}C,\;26^{\circ}C,\;30^{\circ}C$). Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber using thermo-hygrostat. The physiological signal (EEG) for sleep stage were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, mean skin temperature for comfort sleeping was $34.5{\sim}35.4^{\circ}C$. Considering sleep efficiency and mean skin temperature, indoor room temperature of upper limit was $28.1^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.808-813
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• 2008

The study was to evaluate the air-conditioning of sleep algorithm. The algorithm was developed through the analysis of brain waves and MST, the experiments using air conditioner was performed in a apartment bedroom. Five female subjects were participated for the experiment. Eight hours of data collection a day was performed under different algorithm, case A, case B and case C. Physiological signals, EEG, ECG, EOG, and EMG, were obtained using polygraph and converted into digital signal. Then, subjects were asked to answer the questionnaire about their thermal sensation after experiment in bedroom. Sleep stages were classified, then TST, Sleep latency and Sleep efficiency were calculated for the three different air conditioner algorithm. As results, TST, Sleep efficiency, questionnaire showed the higher values for Case B algorism than that for other algorism. On the other hand, SWS latency was lower than for other conditions. Therefore, it was concluded that Case B of the algorithm was the best for comfortable and deep sleep.

• Proceedings of the ESK Conference
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• 1992.10a
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• pp.96-103
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• 1992

To get a comfortable sleep, the most improtant thing is how well we do thermorgulate during the rest in bed before sleeping as well as during sleep. In other works, the ambient temperature of the sleeping room is very improtant in the organization of human sleep. In recent years, the effect of ambient temperature on human sleep has been increasingly stueided. These studies were primarily concerned with the relation between thermorgulatory processes and sleep, and more precisely with the findings that various thermoregulatory processes are inactivated or severly curtailed during REM sleep in a number of animals, also that panting and shivering in heat and cold, respectively, cease during REM sleep in cats. Haskel et al. noted that although REM sleep latency was increased at thigh and low temperature. REM sleep was depressed to a greater extent by lower than by higher temperatures whereas the reverse was obseved for SWS. It has also been found that a load omposed upon thermoregulatory mechanisms should markedly affect sleep processes, and that conversely, sleep in conditions of thermic stress should interfere with adequate thermorgulatory reactions. Sleep in an animala under thermic stress is, on the whole, both shorter and less deep than under normal thermic conditions.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.38-42
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• 1999

문명의 발달과 함께 인간은 사회생활의 증가와 부족한 수면으로 인한 스트레스와 병이 증가하고 있다. 따라서 수면에 대한 관심이 증가하면서 편안하고 쾌적한 수면을 위한 수면환경에 대한 연구가 진행되어지고 있다. 본 연구는 쾌적한 온열환경 제시를 위한 방법으로서 여름철 실내환경이 수면에 미치는 영향을 알아보기 위해 22$^{\circ}C$, 26$^{\circ}C$, 3$0^{\circ}C$의 3가지 온도조건을 제시하고 5명의 피험자를 대상으로 수면다원검사를 실시하여 EEG, EOG, ECG, EMG 등의 생리신호를 측정하였다. 측정된 생리신호를 통해 수면단계분석과 수면효율을 분석한 결과 총 수면시간, SWS latency, 총 수면시간에 대한 SWS 시간의 비율이 26$^{\circ}C$의 조건에서 가장 좋은 결과를 나타내었으며, 22$^{\circ}C$, 3$0^{\circ}C$의 순서로 나타났다. 이러한 분석을 통해 온도차에 따라 수면상태가 달라짐을 관찰할 수 있었고, 여름철에 26$^{\circ}C$ 정도의 실내온도가 편안하고 쾌적한 수면을 위한 실내온열환경임을 알 수 있었다.

• Fashion & Textile Research Journal
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• v.8 no.6
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• pp.713-720
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• 2006

Heat conductivity, height, size, elasticity of pillow, stability of shape, hygroscopicity, ventilation, temperature and easy movability, and so on, are considered to be some of major conditions that affect the comfortable sleep. Considering those factors together, the thermal properties, height, shape and feeling of touch, etc, of pillow must be taken into account. Though studies have been conducted to figure out the physical properties of mattress or pillows from the perspective of factors related to the environment of sleep, they are not enough to be used as an index to evaluate the qualitative aspect of sleep. This study tries to consider the effect of pillow filling materials on the comfortable sleep, for which EEG, ECG, EOG, EMG, RT, etc, are to be measured in an attempt to provide the basic data required in proposing the condition that may lead to a sound and comfortable sleep. Three types of pillows that are sold in the market were used for this research in order to evaluate the quality of sleep depending on the filling materials of pillow. All data were statistically processed and the following conclusions were drawn. It was found that the pillow with feathers provided the best comfort as the pillow A turned out to have the shortest sleeping latency(SL) from the perspective of comfort. The pillow B which used the polyethylene is deemed to be suitable for fatigue relieving purpose as it turned out to have the highest slow wave sleep(SWS), but no statistically significant difference was validated. Moreover, the pillow C which used the natural wool was found to have the narrowest contacting area of the pillow and head and provide a great warm heat comfort that may led to a sound sleep because the temperature below the pillow took the longest time to rise.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.291-297
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• 2010

The sleep homeostatic response significantly affects the state of anesthesia. In addition, sleep recovery may occur during anesthesia, either via a natural sleep-like process to occur or via a direct restorative effect. Little is known about the effects of isoflurane anesthesia on sleep homeostasis. We investigated whether 1) isoflurane anesthesia could provide a sleep-like process, and 2) the depth of anesthesia could differently affect the post-anesthesia sleep response. Nine rats were treated for 2 hours with $ad$ $libitum$ sleep (Control), sleep deprivation (SD), and isoflurane anesthesia with delta-wave- predominant state (ISO-1) or burst suppression pattern-predominant state (ISO-2) with at least a 1-week interval. Electroencephalogram and electromyogram were recorded and sleep-wake architecture was evaluated for 4 hours after each treatment. In the post-treatment period, the duration of transition to slow-wave-sleep decreased but slow wave sleep (SWS) increased in the SD group, but no sleep stages were significantly changed in ISO-1 and ISO-2 groups compared to Control. Different levels of anesthesia did not significantly affect the post-anesthesia sleep responses, but the deep level of anesthesia significantly delayed the latency to sleep compared to Control. The present results indicate that a natural sleep-like process likely occurs during isoflurane anesthesia and that the post-anesthesia sleep response occurs irrespective to the level of anesthesia.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.57-65
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• 1997

As jet lag of modern travel continues to spread, there has been an exponential growth in popular explanations of jet lag and recommendations for curing it. Some of this attention are misdirected, and many of those suggested solutions are misinformed. The author reviewed the basic science of jet lag and its practical outcome. The jet lag symptoms stemed from several factors, including high-altitude flying, lag effect, and sleep loss before departure and on the aircraft, especially during night flight. Jet lag has three major components; including external de synchronization, internal desynchronization, and sleep loss. Although external de synchronization is the major culprit, it is not at all uncommon for travelers to experience difficulty falling asleep or remaining asleep because of gastrointestinal distress, uncooperative bladders, or nagging headaches. Such unwanted intrusions most likely to reflect the general influence of internal desynchronization. From the free-running subjects, the data has revealed that sleep tendency, sleepiness, the spontaneous duration of sleep, and REM sleep propensity, each varied markedly with the endogenous circadian phase of the temperature cycle, despite the facts that the average period of the sleep-wake cycle is different from that of the temperature cycle under these conditions. However, whereas the first ocurrence of slow wave sleep is usually associated with a fall in temperature, the amount of SWS is determined primarily by the length of prior wakefulness and not by circadian phase. Another factor to be considered for flight in either direction is the amount of prior sleep loss or time awake. An increase in sleep loss or time awake would be expected to reduce initial sleep latency and enhance the amount of SWS. By combining what we now know about the circadian characteristics of sleep and homeostatic process, many of the diverse findings about sleep after transmeridian flight can be explained. The severity of jet lag is directly related to two major variables that determine the reaction of the circadian system to any transmeridian flight, eg., the direction of flight, and the number of time zones crossed. Remaining factor is individual differences in resynchmization. After a long flight, the circadian timing system and homeostatic process can combine with each other to produce a considerable reduction in well-being. The author suggested that by being exposed to local zeit-gebers and by being awake sufficient to get sleep until the night, sleep improves rapidly with resynchronization following time zone change.