Sleep Assessment and Research Institute

Tokyo, Japan

Sleep Assessment and Research Institute

Tokyo, Japan
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Okamoto-Mizuno K.,Tohoku Fukushi University | Mizuno K.,Tohoku Fukushi University | Shirakawa S.,Sleep Assessment and Research Institute | Shirakawa S.,National Institute of Mental Health
Behavioral Sleep Medicine | Year: 2016

The purpose of this study was to investigate and compare sleep and skin temperature (Tsk) of preschool children with those of their mothers. The subjects included 18 pairs of preschool children and their mothers. The actigraphic measurement of sleep, Tsk, heart rate, bedroom climate, and the microclimate temperature and humidity (bed climate) were measured. Proximal and distal Tsk, the temperature gradient of distal and proximal Tsk (DPG), and bed climate temperature were significantly lower in the children. Approximately 70% of the children slept without bed covering. Heat dissipation during sleep in preschool children may primarily rely on the proximal Tsk. The lower Tsk than adults, and behavioral thermoregulation, may be important for sleep in preschoolers. © 2016, Routledge. All rights reserved.


Okamoto-Mizuno K.,Tohoku Fukushi University | Mizuno K.,Tohoku Fukushi University | Matsuura N.,Sleep Assessment and Research Institute | Matsuo A.,IWATA Co. | And 4 more authors.
Journal of the Japan Research Association for Textile End-Uses | Year: 2013

Eight healthy male subjects slept from 13:30 to 15:30 under ambient temperature and humidity maintained at 29°C and RH70%, using cotton sheet and polyester bed pad (C) and linen sheet and bed pad (A). A polysomnography, skin temperature, microclimate, bed climate, and subjective sensations were obtained. The number of wakefulness and amount of sleep stage 1 for the C significantly increased compared to those for the A. The bed climate humidity at the waist area for the C was significantly increased than that for the A. The subjective thermal sensation was hotter and sweat sensation showed increased sweating in C compared to the A. These results suggest that material of bed-sheet and bed-pad can affect an increase in the hotter and sweating subjective sensation, number of awakenings, and amount of stage 1 by increasing the bed climate humidity at the waist area. © 2013 Jpn. Res. Assn. Text. End-Uses.


Okamoto-Mizuno K.,Tohoku Fukushi University | Mizuno K.,Tohoku Fukushi University | Matsuura N.,Sleep Assessment and Research Institute | Maruoka T.,Gunze Co. | And 4 more authors.
Journal of the Japan Research Association for Textile End-Uses | Year: 2015

Ten healthy male subjects slept from 13:00 to 15:00 under ambient temperature and humidity maintained at 29°C and 70%RH, respectively. They slept under two conditions: wearing a cotton pajama (C) and wearing a newly designed cold touch pajama (L). A polysomnography, skin temperature, microclimate, bed climate, and subjective sensations were obtained. The amount of stage 3 decreased significantly, while stage 4 tended to increase in L relative to C. Bed climate temperatures of the back area decreased significantly in the initial segment of sleep, and bed climate humidity in the waist area decreased in later sleep segments in L relative to C. Subjective thermal sensation during sleep was cooler in L relative to C. These results suggest that newly designed pajamas decreased bed climate temperature of the back area, reduced bed climate humidity in the waist area, and improved subjective thermal sensation during sleep onset period under mild heat exposure. © 2015 Jpn.Res.Assn.Text.End-Uses.


Komada Y.,Tokyo Medical University | Komada Y.,Neuropsychiatric Research Institute | Asaoka S.,Tokyo Medical University | Asaoka S.,Neuropsychiatric Research Institute | And 7 more authors.
Sleep Medicine | Year: 2012

Background: It has been suggested that the daytime napping patterns of children differ according to racial and cultural backgrounds. The objectives of this study were to describe the daytime nap durations of Japanese nursery school children and to elucidate their relationship to nocturnal bedtimes. Methods: The mothers of 967 children between 0 and 5 years of age recorded sleep logs for 9 consecutive nights. Considering the fact that the subject children were scheduled to take a nap on weekday afternoons, we investigated the proportion of children napping and the relationship between daytime nap duration and nocturnal bedtime on the basis of the data obtained on weekends when children were free from a specific nap schedule. Results: The percentage of children who habitually took a nap was 100% in those under 1 year old, and the percentages were 96.8%, 81.8%, 53.4%, 28.0%, and 9.0% in 1-, 2-, 3-, 4-, and 5-year-old children, respectively. There were significant relationships between nap duration and bedtime in the corresponding night in 2- to 5-year-old children. The " two hours or more" nap group showed a significantly later bedtime than the " no nap" and the " one hour or more but less than two hours" groups in the 2-year-old children (p<0.01 for both). The " two hours or more" nap group showed a significantly later bedtime than the other groups (p<0.01), and the " one hour or more but less than two hours" nap group showed a significantly later bedtime than the " no nap" group in the 3-year-old children (p<0.05). In the 4- to 5-year-old children, the " one hour or more but less than two hours" and " two hours or more" nap groups showed a significantly later bedtime than the " no nap" group (p<0.01 for both). Conclusion: Daytime naps naturally become less common after the third birthday among Japanese nursery school children. The longer the nap durations in 2- to 5-year-old children, the later they went to bed on the corresponding night. © 2011 Elsevier B.V.

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