The circadian rhythm is a variation in physiology and behavior persistent with a cycle length close to 24 hours, and regular sun exposure and dark exposure are is necessary to keep the cycle intact.[1] The circadian cycle in humans is approximately 24-hours in length and must be reset on a daily basis in order to remain in synchronization with the external environment. Sun exposure at the correct times of day is exceptionally important to human health, and when the cycle is disrupted by lack of light, such as that experienced by shift workers, or by those who live constantly indoors, it leads to a feeling of being “out of sync.” Disruption of the circadian rhythm may lead to increased breast-and/or-colorectal cancer risk in women,[2] [3] and research has demonstrated that disruption of circadian rhythms may lead to a profound increase in the risk of heart disease, metabolic syndrome, lung cancer[4] and other cancers.[5] [6]
According to the Journal Sleep Health, morning daylight exposure helps to reset the circadian rhythm or properly maintain it, which leads to better sleep at night.[7] The authors and researchers used a specialized device to measure the type of light that keeps the circadian rhythm of the human body properly set. By comparing workers in different buildings for sleep quality, they determined that those who received higher levels of morning light had considerably better sleep quality. They stated this conclusion: “The present study is the first to measure personal light exposures in office workers using a calibrated device that measures circadian-effective light and relate those light measures to mood, stress, and sleep. The study’s results underscore the importance of daytime light exposures for sleep health.” See also this link: http://sunlightinstitute.org/sleep-quality-is-improved-by-exposure-to-nature-and-sunlight/
Insomnia is a terrible problem in our modern life. To a great extent, that problem could be solved by arising early and taking advantage of an hour of morning sun exposure.
Safely enjoy your sun exposure, sleep tight and improve your health!
[1] Jeanne F. Duffy, M.B.A., Ph.D. and Charles A. Czeisler, Ph.D., M.D. Effect of Light on Human Circadian Physiology. Sleep Med Clin. 2009 Jun; 4(2): 165–177.
[2] Davis S, Mirick DK. Circadian disruption, shift work and the risk of cancer: a summary of the evidence and studies in Seattle. Cancer Causes Control 2006;17:539-45.
[3] Reparto di ChirurgiaGenerale A/D, PoliclinicoSant’Andrea, Sapienza Università di Roma. [Night work as a possible risk factor for breast cancer in nurses. Correlation between the onset of tumors and alterations in blood melatonin levels]. Prof Inferm. 2007;60:89-93
[4] Papagiannakopoulos T, Bauer MR, Davidson SM, Heimann M, Subbaraj L, Bhutkar A, Bartlebaugh J, Vander Heiden MG, Jacks T. Circadian Rhythm Disruption Promotes Lung Tumorigenesis. Cell Metab. 2016 Jul26;(16)30312-2016.07.001.
[5] Vignesh Shanmugam, Amro Wafi, Nawaf Al-Taweel and Dietrich Büsselberg. Disruptions of circadian rhythm
Increase the risk of cancer, metabolic syndrome and cardiovascular disease. Journal of Local and Global Health Science, 2013:3.
[6] Bratsun DA, Merkuriev DV, Zakharov AP, Pismen LM. Multiscale modeling of tumor growth induced by circadian rhythm disruption in epithelial tissue. J Biol Phys. 2015 Aug 21. [Epub ahead of print]
[7] Mariana G. Figueiro, Bryan Steverson, MA, Judith Heerwagen, PhD, Kevin Kampschroer, MA, Claudia M. Hunter, PhD, Kassandra Gonzales, MS, Barbara Plitnick, RN, Mark S. Rea, PhD. The impact of daytime light exposures on sleep and mood in office workers. Sleep Health June 2017;3:204-215.