Olfactory stimulation has been reported to trigger waking up during night sleep, and to affect the sympathetic nervous system and blood pressure of humans via the circadian clock system. Olfactory stimulation may promote better sleep health in Japanese students living in 24-hour society, but no studies have been done on this hypothesis. The purpose of this study is to make it clear what are the effects of makeup, perfume and skin care products on the circadian typology, sleep habits and mental health of female Japanese students aged 18 - 30 using an integrated questionnaire. Students who regularly used skin care products went to bed earlier on both weekdays and weekends and also got up earlier in the morning on weekdays than those who did not (p < 0.05). The students who wore makeup two or more days per week showed higher sleep quality than those who were makeup only one day a week or less (p < 0.05). The students who regularly carried out a hair care regimen showed a significantly lower frequency of becoming angry after a small trigger and of losing control due to anger than those who did not. Makeup, perfume and skin care products might be possible to be related to better sleep health for students. Moreover, hair care may help maintain mental health in female students. Makeup, perfume and skin care products might be implied to become chemical, mechanical and/or psychological stimuli as zeitgebers for circadian clock of students.
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