ArticleJournal of physiological anthropology2021
Is the use of high correlated color temperature light at night related to delay of sleep timing in university students? A cross-country study in Japan and China.
Article in Journal of physiological anthropology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.
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Who cites it
11 citing papers in PubMed, 23 citations in OpenAlex.
- Exploring the Effects of Blue Light on Circadian Rhythm in SD Rat.Nature and science of sleep · 2026Article
- Light at night and circadian rhythms: from the perspective of physiological anthropology research.Journal of physiological anthropology · 2024Article
- Improving adjustment to daylight saving time transitions with light.Scientific reports · 2024Article
- Time-Dependent Effects of Altered Prebedtime Light Exposure in Enclosed Spaces on Sleep Performance Associated with Human States.Nature and science of sleep · 2024Article
- Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning.Clocks & sleep · 2023Article
- Article
- Review on age-related differences in non-visual effects of light: melatonin suppression, circadian phase shift and pupillary light reflex in children to older adults.Journal of physiological anthropology · 2023Review
- The next stage of physiological anthropology.Journal of physiological anthropology · 2023Article
- Circadian phase advances in children during camping life according to the natural light-dark cycle.Journal of physiological anthropology · 2022Article
- Intake of L-serine before bedtime prevents the delay of the circadian phase in real life.Journal of physiological anthropology · 2022Article
- A review of the current state of research on artificial blue light safety as it applies to digital devices.Heliyon · 2022Review
Corrections and comments
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Authors and funding
8 authors at 4 institutions in 2 countries.
Funding
Abstract
backgroundBlue-enriched white light at night has the potential to delay the circadian rhythm in daily life. This study was conducted to determine whether the use of high correlated color temperature (CCT) light at home at night is associated with delay of sleep timing in university students.
methodsThe survey was conducted in 2014-2015 in 447 university students in Japan and 327 students in China. Habitual sleep timing and type of CCT light at home were investigated by using a self-administered questionnaire. The Japanese students were significantly later than the Chinese students in bedtime, wake time, and midpoint of sleep. They were asked whether the lighting in the room where they spend most of their time at night was closer to warm color (low CCT) or daylight color (high CCT). The amount of light exposure level during daily life was measured for at least 1 week by the use of a light sensor in 60 students in each country.
resultsThe percentages of participants who used high CCT lighting at night were 61.6% for Japanese students and 80.8% for Chinese students. Bedtime and sleep onset time on school days and free days were significantly later in the high CCT group than in the low CCT group in Japan. The midpoint of sleep in the high CCT group was significantly later than that in the low CCT group on free days but not on school days. On the other hand, none of the sleep measurements on school days and free days were significantly different between the high CCT and low CCT groups in China. Illuminance level of light exposure during the night was significantly higher in Japanese than in Chinese, but that in the morning was significantly higher in China than in Japan.
conclusionsThe use of high CCT light at night is associated with delay of sleep timing in Japanese university students but not in Chinese university students. The effects of light at night on sleep timing and circadian rhythm may be complicated by other lifestyle factors depending on the country.
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