This paper conducts an experiment to explore the physiology response of a group of subjects during nightly sleep, after their exposure to red, green, and blue monochromatic light during the forenoon. Informed consent was obtained from the subjects, who were nine male college students with normal color vision. The subjects' eyes were exposed to 638nm, 523nm and 465nm monochromatic LED light sources, with irradiances of 73.4μW/cm^2, 74.2μW/cm^2, and 76.9μW/cm^2, respectively. The experiment measured the subjects' saliva melatonin, urinary melatonin, rectal temperature, OSA, and polysomonogram,. In statistical analysis, the methods of ANOVA (with the primary factor being the monochromatic lighting conditions) and Bonferroni were employed to make a multi comparison of the mean values of the varying measurements mentioned above. It can be found that the rectal temperature value under 465nm was significantly higher than that under 638nm (P<0.01). According to the Electroencephalogram during the whole sleeping process, the measurements under 465nm condition were significantly higher than those under 523nm condition during the 2nd sleep cycle (P<0.05). Moreover, through a comparison between the percentage of varied sleep stages on testing day and that of the contrasting day, it can be found that the duration of sleep stage 4 with exposure to the monochromatic light of 465 nm reduced significantly than that with exposure to the monochromatic light of 638 nm (p<0.1). Therefore, exposure to the monochromatic light with the wavelength of 465 nm has the effect of preventing the sharp drop of rectal temperature and reducing deep sleep.
View full abstract