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Author Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D.
Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
Year 2013 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 16 Pages 1554-1558
Keywords Human Health; Adult; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight; Young Adult; Circadian Rhythm
Abstract The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks.
Address Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309-0354, USA. kenneth.wright@colorado.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23910656; PMCID:PMC4020279 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 505
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Author Stothard, E.R.; McHill, A.W.; Depner, C.M.; Birks, B.R.; Moehlman, T.M.; Ritchie, H.K.; Guzzetti, J.R.; Chinoy, E.D.; LeBourgeois, M.K.; Axelsson, J.; Wright, K.P.J.
Title Circadian Entrainment to the Natural Light-Dark Cycle across Seasons and the Weekend Type Journal Article
Year 2017 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol
Volume 27 Issue 4 Pages 508-513
Keywords Human Health
Abstract Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night leads to late circadian and sleep timing [1-3]. We have previously shown that exposure to a natural summer 14 hr 40 min:9 hr 20 min light-dark cycle entrains the human circadian clock to solar time, such that the internal biological night begins near sunset and ends near sunrise [1]. Here we show that the beginning of the biological night and sleep occur earlier after a week's exposure to a natural winter 9 hr 20 min:14 hr 40 min light-dark cycle as compared to the modern electrical lighting environment. Further, we find that the human circadian clock is sensitive to seasonal changes in the natural light-dark cycle, showing an expansion of the biological night in winter compared to summer, akin to that seen in non-humans [4-8]. We also show that circadian and sleep timing occur earlier after spending a weekend camping in a summer 14 hr 39 min:9 hr 21 min natural light-dark cycle compared to a typical weekend in the modern environment. Weekend exposure to natural light was sufficient to achieve approximately 69% of the shift in circadian timing we previously reported after a week's exposure to natural light [1]. These findings provide evidence that the human circadian clock adapts to seasonal changes in the natural light-dark cycle and is timed later in the modern environment in both winter and summer. Further, we demonstrate that earlier circadian timing can be rapidly achieved through natural light exposure during a weekend spent camping.
Address Department of Integrative Physiology, Sleep and Chronobiology Laboratory, University of Colorado Boulder, Boulder, CO 80309-0354, USA. Electronic address: kenneth.wright@colorado.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:28162893 Approved no
Call Number LoNNe @ kyba @ Serial 1633
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Author Sanders, D.; Kehoe, R.; Cruse, D.; van Veen, F.J.F.; Gaston, K.J.
Title Low Levels of Artificial Light at Night Strengthen Top-Down Control in Insect Food Web Type Journal Article
Year 2018 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol
Volume 28 Issue 15 Pages 2474-2478.e3
Keywords Ecology; Animals
Abstract Artificial light has transformed the nighttime environment of large areas of the earth, with 88% of Europe and almost 50% of the United States experiencing light-polluted night skies [1]. The consequences for ecosystems range from exposure to high light intensities in the vicinity of direct light sources to the very widespread but lower lighting levels further away [2]. While it is known that species exhibit a range of physiological and behavioral responses to artificial nighttime lighting [e.g., 3-5], there is a need to gain a mechanistic understanding of whole ecological community impacts [6, 7], especially to different light intensities. Using a mesocosm field experiment with insect communities, we determined the impact of intensities of artificial light ranging from 0.1 to 100 lux on different trophic levels and interactions between species. Strikingly, we found the strongest impact at low levels of artificial lighting (0.1 to 5 lux), which led to a 1.8 times overall reduction in aphid densities. Mechanistically, artificial light at night increased the efficiency of parasitoid wasps in attacking aphids, with twice the parasitism rate under low light levels compared to unlit controls. However, at higher light levels, parasitoid wasps spent longer away from the aphid host plants, diminishing this increased efficiency. Therefore, aphids reached higher densities under increased light intensity as compared to low levels of lighting, where they were limited by higher parasitoid efficiency. Our study highlights the importance of different intensities of artificial light in driving the strength of species interactions and ecosystem functions.
Address Environment and Sustainability Institute, University of Exeter, Penryn, Penryn, Cornwall TR10 9FE, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:30057304 Approved no
Call Number GFZ @ kyba @ Serial 2518
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Author Kumar, P.; Ashawat, M.S.; Pandit, V.; Sharma, D.K.
Title Artificial Light Pollution at Night: A Risk for Normal Circadian Rhythm and Physiological Functions in Humans Type Journal Article
Year 2019 Publication (up) Current Environmental Engineering Abbreviated Journal Cee
Volume 6 Issue 2 Pages 111-125
Keywords Human Health; Review
Abstract From the past three to four decades, ecologists and scientists have exhaustively studied the effect of increased artificial light pollution at night on the ecological and physiological behavior of mammals. The Suprachiasmatic Nuclei (SCN) or master clock in the brain of mammals including humans synchronizes the physiological functions with the light: dark cycle. The prolongation of light period in the light: dark cycle disrupts the circadian rhythm of mammals causing several negative or modified physiological consequences. Changed physiological level of melatonin, an important endocrine hormone, had been identified as an important factor causing different consequences such as cancer, diabetes mellitus, metabolic disturbances, oxidative stress, and depression. The presence of artificial light at night is the demand of the era but thoughts must be given to the prevention of consequences due to artificial light pollution and ‘how much is needed’. The review paper discusses the effect of artificial light pollution on the biological clock of humans and associated negative physiological consequences. Further, the paper also briefly discusses the economics of light pollution and measures needed to prevent physiological disorders in humans.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-7178 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2695
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Author Leung, J.M.; Martinez, M.E.
Title Circadian Rhythms in Environmental Health Sciences Type Journal Article
Year 2020 Publication (up) Current Environmental Health Reports Abbreviated Journal Curr Environ Health Rep
Volume in press Issue Pages
Keywords Review; Human Health; Asthma; Biomarkers; Breast cancer; Circadian rhythms; DNA methylation; Environmental health
Abstract PURPOSE OF REVIEW: This review aims to explore how circadian rhythms influence disease susceptibility and potentially modify the effect of environmental exposures. We aimed to identify biomarkers commonly used in environmental health research that have also been the subject of chronobiology studies, in order to review circadian rhythms of relevance to environmental health and determine if time-of-day is an important factor to consider in environmental health studies. Moreover, we discuss opportunities for studying how environmental exposures may interact with circadian rhythms to structure disease pathology and etiology. RECENT FINDINGS: In recent years, the study of circadian rhythms in mammals has flourished. Animal models revealed that all body tissues have circadian rhythms. In humans, circadian rhythms were also shown to exist at multiple levels of organization: molecular, cellular, and physiological processes, including responding to oxidative stress, cell trafficking, and sex hormone production, respectively. Together, these rhythms are an essential component of human physiology and can shape an individual's susceptibility and response to disease. Circadian rhythms are relatively unexplored in environmental health research. However, circadian clocks control many physiological and behavioral processes that impact exposure pathways and disease systems. We believe this review will motivate new studies of (i) the impact of exposures on circadian rhythms, (ii) how circadian rhythms modify the effect of environmental exposures, and (iii) how time-of-day impacts our ability to observe the body's response to exposure.
Address Department of Environmental Health Sciences, Columbia University, 630 West 168th Street, Room 16-421C, New York, NY, USA. mem2352@cumc.columbia.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2196-5412 ISBN Medium
Area Expedition Conference
Notes PMID:32662059 Approved no
Call Number GFZ @ kyba @ Serial 3055
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