Circadian Shifts (07-26-21)

Khodasevich and teammates investigated how artificial light can support circadian rhythms.  They “measured light exposure and wrist temperature among residents of an urban area during each of the four seasons. . . . Our results demonstrate that humans are minimizing natural seasonal differences in light exposure, and that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized. . . . . Our evaluation of light exposure, and how it is partitioned among daytime and night-time hours, supported our hypothesis that individuals living in urban environments dim out their days and light up their nights. . . . Seasonal biology in humans is not well-understood, therefore, it is unknown what downstream effects this disconnect from natural light cycles may have on physiology and health. . . . our study revealed that differential light exposure, within the range seen in everyday life, can lead to shifts in circadian physiology within the general population.”

Dennis Khodasevich, Susan Tsui, Darwin Keung, Debra Skene, Victoria Revell, and Micaela Martinez. 2021.  “Characterizing the Modern Light Environment and Its Influence on Circadian Rhythms.”  Proceedings of the Royal Society B, https://doi.org/10.1098/rspb.2021.0721