The purpose of this study was to comprehensively evaluate sleep and to investigate ways to improve the sleep environment in the disaster situation. We experimentally reproduced a sleep environment that simulates staying in evacuation shelter (evacuation shelter trial) or in car seats (car trial) during a disaster in nine young healthy males and conducted sleep experiments during the winter. As a result, compared to the control trial conducted at home (control trial), we were unable to confirm the effect of the sleep environment that simulated staying at an evacuation shelter or in a car on falling asleep, but it was suggested objectively and subjectively that coldness and difficulty in turning over interfered with sleep maintenance in the evacuation shelter and car trials. It was suggested that the quality of sleep might be secured objectively and subjectively by devising bedding such as cardboard beds to prevent coldness when staying in evacuation shelters, and by using cushions to eliminate steps to make turning over easier when staying in cars.

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The purpose of this study was to investigate that the effect of different types of spectral distributions on psychophysiological states during light exposure and the succeeding sleep. Participants were 20 young male adults without problems of sleep. Light conditions were five; incandescent lamp, incandescent lamp color or day white light color polychromatic LEDs using violet or blue excitation light. The light of violet excitation LEDs has more broad spectral distribution similar to natural light than that of blue excitation LEDs. Participants slept for seven hours after light exposure for about 100 minutes. The calculated non-visual effect from the short wavelength component was maximum in the day white light color LEDs using violet excitation light (P-LED_C). However, the falling rate of rectal temperature during light exposure in the day white light color LEDs using blue excitation light (B-LED_C) was worst of the five. Moreover, the sleep latency in B-LED_C was longest of the five. Therefore, B-LED_C showed the effect which was the most undesirable for sleep. The present study suggested that not only the optical characteristics of the short wavelength component but also the difference between the excitation light and the long wavelength component should be considered.

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