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Characterizing the modern light environment and its influence on circadian rhythms

Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, w...

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Autores principales: Khodasevich, Dennis, Tsui, Susan, Keung, Darwin, Skene, Debra J., Revell, Victoria, Martinez, Micaela E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8292753/
https://www.ncbi.nlm.nih.gov/pubmed/34284625
http://dx.doi.org/10.1098/rspb.2021.0721
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author Khodasevich, Dennis
Tsui, Susan
Keung, Darwin
Skene, Debra J.
Revell, Victoria
Martinez, Micaela E.
author_facet Khodasevich, Dennis
Tsui, Susan
Keung, Darwin
Skene, Debra J.
Revell, Victoria
Martinez, Micaela E.
author_sort Khodasevich, Dennis
collection PubMed
description Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. 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.
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spelling pubmed-82927532021-07-31 Characterizing the modern light environment and its influence on circadian rhythms Khodasevich, Dennis Tsui, Susan Keung, Darwin Skene, Debra J. Revell, Victoria Martinez, Micaela E. Proc Biol Sci Ecology Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. 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. The Royal Society 2021-07-28 2021-07-21 /pmc/articles/PMC8292753/ /pubmed/34284625 http://dx.doi.org/10.1098/rspb.2021.0721 Text en © 2021 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Ecology
Khodasevich, Dennis
Tsui, Susan
Keung, Darwin
Skene, Debra J.
Revell, Victoria
Martinez, Micaela E.
Characterizing the modern light environment and its influence on circadian rhythms
title Characterizing the modern light environment and its influence on circadian rhythms
title_full Characterizing the modern light environment and its influence on circadian rhythms
title_fullStr Characterizing the modern light environment and its influence on circadian rhythms
title_full_unstemmed Characterizing the modern light environment and its influence on circadian rhythms
title_short Characterizing the modern light environment and its influence on circadian rhythms
title_sort characterizing the modern light environment and its influence on circadian rhythms
topic Ecology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8292753/
https://www.ncbi.nlm.nih.gov/pubmed/34284625
http://dx.doi.org/10.1098/rspb.2021.0721
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