水野 一枝

BACKGROUND: We investigated the relationship between sleep, ambient climate, and bed climate in school-aged children during a one-night stay in a simulated shelter in a gymnasium to demonstrate the effect of ambient climate, and bed climate on sleep. METHODS: We obtained measurements during a one-night stay in a school gymnasium (C), days before C (BC), on the day after (A1), and on the second day after C (A2) in 13 healthy school-aged children during summer. Sleep was evaluated using an actigraph, and the temperature and humidity of the bedrooms in the participants' homes and in the gymnasium were monitored for 3 days before and after C. The bed climate of the chest and foot areas was measured for two nights before and after C. The participants were asked to report on their subjective sleep estimations and thermal sensations two nights before and after C. RESULTS: The ambient temperature in C was significantly higher than that in BC at the initial 180 min, while it significantly decreased compared to A1 and A2 in the last 100 min. The ambient humidity was significantly higher in both C and BC compared to A1 and A2. The sleep efficiency index decreased significantly in C (43±4.8%) compared to other conditions. Sleep time was significantly shorter in C than in other conditions during the initial 195 min. The increase in the bed climate temperature of the chest area in C was significantly delayed compared to that in the other conditions, around the initial 30 min after the lights were off. Subjective estimation revealed that in C, 85% of the participants were out of their sleeping bag at sleep onset, and their sleep was disturbed by heat (77%). CONCLUSIONS: Our study revealed that the disturbed sleep patterns observed with children in a simulated shelter may be related to a delayed increase in bed climate temperature in the chest area. This delayed increase could be related to the children not entering the sleeping bag and a delayed chest skin temperature increase during the sleep onset period.

【目的】SIDSの多い冬季に乳児と母親の寝室内照度,寝床内気候,睡眠の実態を比較し問題点を検討することを目的とした。【方法】生後2～3ヵ月の乳児と母親5組を対象に冬季に在宅で3夜,寝室内温湿度と照度,寝床内気候,アクチグラフによる睡眠を測定した。母親には睡眠日誌,寝具,寝衣の調査用紙の記載,起床時に寝床内温冷感,湿潤感の主観調査を実施した。【結果】就寝時の寝室内の照度は0.1±0.6lx,授乳時の最高照度は96.4lxであった。寝床内温湿度は,背部,足部ともに乳児が母親より有意に高かった(p<0.01)。睡眠変数は母子間で有意差はなかった。【結語】SIDS予防を含めた睡眠環境調整及び睡眠について養育者に情報提供や相談を行う必要性が示唆された。また,冬季において,乳児の寝床内温湿度は母親より高いことから,乳児の就寝時には発汗の有無の確認を推奨したいと考える。(著者抄録)

This study aimed to examine the sleep habits in pairs of Japanese high school students and their mothers in the summer and autumn. Nineteen pairs of high school students and their mothers participated in this study. Wrist actigraphy, subjective sleep evaluations, and bedroom environmental measurements (temperature, humidity, and light) were performed for a duration of one week. The results of a split-plot analysis of variance revealed no significant difference in the actigraphically evaluated time spent in bed (TIB) between the seasons and between the mothers and students. The TIB was approximately 6 h on weekdays, and significantly lengthened to approximately 7 h on weekends (p < 0.05). The average sleep efficiency values recorded were higher than 90%. The mothers showed significantly advanced sleep phases compared to those of the students (p < 0.05). In addition, the waking time on Monday morning was significantly correlated between the mothers and students in the summer and autumn (p < 0.05). A perceived sleep loss “almost every day” or “several times per week” was reported by approximately half of the mothers and students in each season. The students occasionally fell into nocturnal sleep with the room light turned on. These results suggest that sleep hygiene education considering life habit characteristics is required to ensure sufficient sleep time.

<p>夏期の睡眠温熱環境が子供の睡眠に及ぼす影響を検討することを目的とした．被験者は，健康な小学校低学年と高学年それぞれ12名であった．夏期と秋期に被験者の自宅でアクチグラフによる活動量，寝室内温湿度を7日間連続測定し，期間中の二晩に夜間就寝中の寝床内気候を測定し，就寝前，起床時の主観的睡眠感，温冷感，快適感を申告してもらった．寝室内温湿度は夏で秋よりも有意に温度と湿度が高かったが，学年差はなかった．睡眠では，夏期と秋期に差はなかったが，低学年では高学年よりも就寝時刻が早く，睡眠時間，睡眠時の活動量，覚醒時間，覚醒回数が有意に増加した．寝床内温度は睡眠後半で秋期は低学年が高学年よりも高く，夏期は低学年が高学年よりも低かった．就寝時の温冷感は低学年で高学年よりも有意に暖かい申告であった．低学年と高学年では寝室内温湿度に差はなくとも，睡眠や寝床内温度が異なり，高学年よりも低学年で寝室環境をより暖かく感じている可能性が示唆された．</p>

Eight healthy young female volunteers slept from 23:00 to 7:00 in a climate chamber that was controlled under the following conditions : 25℃/60% RH for the first hour, followed by an increase to 28℃/65% RH in the second hour, and then a decrease to 27℃/60% RH in the last six hours. The skin temperature (T_<Sk>) and bed climate were measured continually through the night at time intervals of 3 min. Body movement was measured continually by means of video taping. The covered area was scored from body movement recordings at time intervals of 1 min. The 17 body sites were scored visually. The time of body covering significantly differed depending on ambient temperature changes in the neck, shoulder, and upper extremities, while no change was observed in the trunk and lower extremities. The time of body covering was significantly shorter in the upper extremities, neck, and shoulder compared to the other sites of the body. No significant difference was observed in skin temperature and bed climate of the chest area, regardless of ambient temperature change. The bed climate of the foot area significantly increased when ambient temperature increased. These results indicate that body covering behavior, which is one of the mechanisms of behavioral thermoregulation, is active during sleep. The covering area may differ depending on the body site, which is more sensitive in the upper extremities compared to the lower extremities or trunk.

二つの異なる特別養護老人ホーム入所者の寝床内気候, 睡眠感, 主観的気分と眠気の日内変動を比較した.調査対象は, 介護体制の異なる東京都心(T)と長野県郊外(N)にある特別養護老人ホーム入所者計30名(東京22名, 長野8名)とし, さらにADL(日常生活活動)が自立している群(T-high, N-high)と自立していないねたきりの群(T-low, N-low)にわけて比較した.測定項目は寝室内, 寝床内温湿度, 起床時の睡眠感, 主観的眠気, 活力, 気分のリズムとした.夜間の室内温湿度は, Nで有意に温度が低く, 湿度が高かった.日中の背部の寝床内温度は, T-highでN-highよりも有意に低かった.夜間の寝床内気候に群による差はみられず, 32～34℃, 50～60%RHの間に保たれていた.日中の眠気はT-highでN-highより有意に低く, T-lowでもN-lowより低い傾向であった.睡眠感はT-high, T-lowでN-high, N-lowよりも有意に高かった.ADLは同じでも, ホームにより睡眠感は差がみられ, 介護体制を改善していくことで睡眠感が改善する可能性が示唆された.

The objective of this study was to confirm the effects of ADL (Activity of Daily Living) and gender on circadian rhythms of the elderly in a nursing home. Twenty-one elderly volunteers, aged over 65 years, were divided in four groups depending on their ADL and gender : subjects with almost no problem in ADL (H males, H females) and those who were almost bedridden (L males, L females). Oral temperature, heart rate, blood pressure, time of sleep and wake, subjective sleepiness, overall feeling and vitality were measured every 4 hours during the day continuously for six days. The circadian rhythm was calculated by using the least squares fit of cosine function. Subjective sleep quality was also surveyed. In the sleep / wake rhythm, the mesor was significantly higher in L males compared to the other groups and the amplitude was significantly lower in L females compared to other groups. The subjective sleepiness was higher in L males compared to the other groups and L females showed a higher sleepiness compared to H females. No significant difference among the group was observed in subjective sleep quality. In conclusion, these results indicate that the subjective sleepiness and sleep / wake rhythm differ depending on ADL and gender, although no significant difference was observed in physiological parameters. ADL and gender based difference in subjective sleepiness and sleep / wake rhythm should be taken into account with regard to the care of the elderly in nursing homes.

就寝前の寝床内の下肢部加温が, 睡眠中の生理反応および寝床内気候, 睡眠感に及ぼす影響を若年者と高年者で比較した。対象は, 健康な若年女性5名(平均年齢21.8歳), 高年女性5名(平均年齢60.3歳)とした。実験は, 二つの人工気候室を用い, 1室は居間を想定し20℃, 60%RH, 2室は寝室を想定し13℃, 60%RHに保った。就寝前に1室で30分安静を保ち, その後2室で電気敷毛布であらかじめ下肢部を加温した寝具で23:00～7:00まで就寝してもらった。電気敷毛布の電源は入床と同時に切った。寝床内気候, 体動, 皮膚温, 心拍数は連続測定し, 主観申告(温冷感, 快適感, 湿潤感, 睡眠感)は入床時と起床時に, それぞれ申告してもらった。胸部の寝床内温度に有意差は見られなかったが, 足部は有意に高年者の方が低かった。安静覚醒時の皮膚温は, 足先, 指は高年者で有意に高く逆に胸は若年者の方が有意に高かった。就寝時では胸部, 平均皮膚温が高年者で有意に低かった。心拍数には有意差は見られなかった。睡眠感は睡眠維持の因子が高年者で有意に良かった。就寝前の寝床内加温に対する胸部および平均皮膚温, 足部の寝床内気候, 主観的睡眠感に差が見られたことから, 年齢差を考慮した使用方法や温度設定の検討が必要であることが示唆された。

就寝前の下肢加温が, 睡眠中の生理反応および寝床内気候, 睡眠感に及ぼす影響を若年者と高年者で比較した.対象は, 健康な若年女性5名(平均年齢21.8歳), 高年女性5名(平均年齢60.3歳)とした.実験は, 2室の人工気候室を用い, 1室は居間を想定し20℃, 60%RH, 2室は寝室を想定し13℃, 60%RHに保った.就寝前に1室で炬燵を用いて30分下肢を加温し, その後2室で23:00～7:00まで就寝してもらった.心拍数, 皮膚温, 体動, 寝床内気候は連続測定し, 温冷感, 快適感, 湿潤感, 睡眠感は就寝前, 起床時にそれぞれ申告を行った.就寝時の心拍数に有意差はみられなかった.下肢加温時の皮膚温は, 指は高年者で有意に高く, 逆に胸, 下腿, 平均皮膚温は有意に低かった.就寝時では高年者で胸が有意に低い以外, 年齢による差はみられなかった.寝床内気候は若年者, 高年者ともに32～33℃, 35～50%RHに保たれ, 睡眠感もよく, 有意差はみられなかった.下肢加温後の睡眠では, 高年者は睡眠感, 胸以外の皮膚温, 寝床内気候は若年者と同じレベルを保つ可能性が示唆された.

The purpose of this study was to examine the effects of a truss mattress upon sleep and bed climate. The truss mattress which has been designed to decrease the pressure and bed climate humidity was tested. Six healthy female volunteers with a mean age of 23.3 years, served as subjects. The experiment was carried out under two conditions: a truss mattress (T) and a futon (F) (Japanese bedding). The ambient temperature and relative humidity were controlled at 19-20℃, and RH 50-60% respectively. Sleep was monitored by an EEG machine and the rectal temperature, skin temperature and bed climate were also measured continuously. Subjective evaluations of bed and sleep were obtained before and after the recording sessions. No significant difference was observed in the sleep parameters and time spent in each sleep stage. Rectal temperature was significantly lower in T than F. Although there was no significant difference in bed climate over the T/F, the temperature under T/F was significantly higher in T. No significant difference was observed in subjective sleep evaluation. The subjective feeling of the mattress was significantly warmer in F than T before sleep. These results suggest that although T does not disturb the sleep parameters and the bed climate is maintained at the same level as with F, it may affect rectal temperature which can be due to low thermal insulation.

Bedroom and bed climate of the elderly in a nursing home were surveyed. Twenty-two elderly subjects were divided into four groups depending on their Activity of Daily Living (ADL) and gender. The four groups were: male and female subjects with almost no problems in daily life and an ADL score higher than 5 [H males, H females] and male and female subjects who normally stayed in bed all day with an ADL score lower than 2 [L males, L females]. The temperature and humidity of the bedroom and bed climate were measured continuously for 24 hours. Bedding and clothing condition, subjective sensational vote and subjective sleep evaluation were surveyed before and after sleep for five days continuously. In the daytime, bedroom and bed climate temperature was significantly lower in H females than in the other groups. At night, no significant effect of gender and ADL was observed in bed climate, which was maintained at 33～35℃, RH50～60% in all the groups. Bedding under the body increased significantly in L males and L females compared with H males and H females. The number of underwear increased significantly in H females. Subjective sleep evaluation was significantly better in H females than the other groups. These results suggest that ADL and gender based differences should be taken into account with regard to the care of the elderly in a nursing home.