By Marc Sorenson, EdD, Sunlight Institute
Recently I ran across two interesting scientific papers that related to each other in a way that was probably unknown to the investigators and authors of either paper. Both papers had to do with circadian rhythms, which are biological cycles that recur in approximately 24-hour intervals. On awakening to sunlight, the chemical serotonin—a natural mood enhancer—is increased in blood circulation, and at night, when the sun sets, melatonin—a natural relaxer—takes over and helps us to sleep soundly; at least that is the way it should work. There are many other circadian rhythms that operate throughout our daily life, and when they are operating properly, we feel better and function at a higher level of health and happiness.
The first of the scientific papers was called “Electric light, particularly at night, disrupts human circadian rhythmicity: is that a problem?”[i] In that study the authors make the point that almost all life forms have developed circadian rhythms in which daily oscillations in physiology occur, and that disruptions of those rhythms can result in depression, cancers, obesity, diabetes and depression. The physiology, they report, is meant to work on a sunrise to sunset cycle, and that that cycle is becoming increasingly disrupted by electric lighting, which may be responsible for disease.
The second paper was called, Circadian clocks optimally adapt to sunlight for reliable synchronization.[ii] In it, the authors explain that circadian rhythms are best synchronized by sunlight. It therefore occurs to me that to escape the ravages of electric light disease, it would be a good idea to reset our biological clocks daily by being out in the morning sunlight when possible, and avoiding long hours of electric light exposure at night. This could be on of the best therapies possible when we feel “out of synch.” And, catching some sunlight throughout the day would also keep serotonin levels higher and keep our moodiness in check. All of us know that we feel better when we are in the sunlight. This, coupled with enhancement of health, demonstrates that our friend, the sun, is an essential companion for optimal living.
[i] Stevens RG, Zhu Y. Electric light, particularly at night, disrupts human circadian rhythmicity: is that a problem? Philos Trans R Soc Lond B Biol Sci. 2015 May 5;370(1667).
[ii] Hasegawa Y, Arita M. Circadian clocks optimally adapt to sunlight for reliable synchronization. J R Soc Interface. 2013 Dec 18;11(92):20131018.