TLDR Bright light during the day doesn't change most human clock genes but may slightly increase Rev-erb-ß.
The study, conducted on seven healthy men, explored the impact of bright light exposure on the expression of clock genes in hair follicular and root cells. It concluded that a single day of bright light exposure during daytime did not significantly alter the expression of most clock genes, such as Per1, Per2, Per3, Cry1, Cry2, Rev-erb-a (Nr1d1), and Dec1. However, there was a tendency for increased expression of Rev-erb-ß (Nr1d2) under bright light conditions. The findings imply that more prolonged exposure to bright light might be necessary to affect clock gene expression in humans. The study's small sample size and infrequent sampling may have limited its ability to detect minor gene expression changes.
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January 2023 in “International Journal of Molecular Sciences” Hair follicles could be used to noninvasively monitor our body's internal clock and help identify risks for related diseases.
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September 2013 in “Journal of Investigative Dermatology” BMAL1 and Period1 genes can influence human hair growth.
