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Author Lowden, A.; Lemos, N.; Gonçalves, B.; Öztürk, G.; Louzada, F.; Pedrazzoli, M.; Moreno, C.
Title Delayed Sleep in Winter Related to Natural Daylight Exposure among Arctic Day Workers Type Journal Article
Year 2018 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep
Volume 1 Issue 1 Pages 105-116
Keywords Human Health
Abstract Natural daylight exposures in arctic regions vary substantially across seasons. Negative consequences have been observed in self-reports of sleep and daytime functions during the winter but have rarely been studied in detail. The focus of the present study set out to investigate sleep seasonality among indoor workers using objective and subjective measures. Sleep seasonality among daytime office workers (n = 32) in Kiruna (Sweden, 67.86° N, 20.23° E) was studied by comparing the same group of workers in a winter and summer week, including work and days off at the weekend, using actigraphs (motion loggers) and subjective ratings of alertness and mood. Actigraph analyses showed delayed sleep onset of 39 min in winter compared to the corresponding summer week (p < 0.0001) and shorter weekly sleep duration by 12 min (p = 0.0154). A delay of mid-sleep was present in winter at workdays (25 min, p < 0.0001) and more strongly delayed during days off (46 min, p < 0.0001). Sleepiness levels were higher in winter compared to summer (p < 0.05). Increased morning light exposure was associated with earlier mid-sleep (p < 0.001), while increased evening light exposure was associated with delay (p < 0.01). This study confirms earlier work that suggests that lack of natural daylight delays the sleep/wake cycle in a group of indoor workers, despite having access to electric lighting. Photic stimuli resulted in a general advanced sleep/wake rhythm during summer and increased alertness levels.
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ISSN (up) 2624-5175 ISBN Medium
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Call Number GFZ @ kyba @ Serial 2137
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Author Prayag, A.; Münch, M.; Aeschbach, D.; Chellappa, S.; Gronfier, C.
Title Light Modulation of Human Clocks, Wake, and Sleep Type Journal Article
Year 2019 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep
Volume 1 Issue 1 Pages 193-208
Keywords Human Health; Review
Abstract Light, through its non-imaging forming effects, plays a dominant role on a myriad of physiological functions, including the human sleep–wake cycle. The non-image forming effects of light heavily rely on specific properties such as intensity, duration, timing, pattern, and wavelengths. Here, we address how specific properties of light influence sleep and wakefulness in humans through acute effects, e.g., on alertness, and/or effects on the circadian timing system. Of critical relevance, we discuss how different characteristics of light exposure across the 24-h day can lead to changes in sleep–wake timing, sleep propensity, sleep architecture, and sleep and wake electroencephalogram (EEG) power spectra. Ultimately, knowledge on how light affects sleep and wakefulness can improve light settings at home and at the workplace to improve health and well-being and optimize treatments of chronobiological disorders.
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ISSN (up) 2624-5175 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2266
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Author Walbeek, T.J.; Harrison, E.M.; Soler, R.R.; Gorman, M.R.
Title Enhanced Circadian Entrainment in Mice and Its Utility under Human Shiftwork Schedules Type Journal Article
Year 2019 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep
Volume 1 Issue 3 Pages 394-413
Keywords Animals
Abstract The circadian system is generally considered to be incapable of adjusting to rapid changes in sleep/work demands. In shiftworkers this leads to chronic circadian disruption and sleep loss, which together predict underperformance at work and negative health consequences. Two distinct experimental protocols have been proposed to increase circadian flexibility in rodents using dim light at night: rhythm bifurcation and T-cycle (i.e., day length) entrainment. Successful translation of such protocols to human shiftworkers could facilitate alignment of internal time with external demands. To assess entrainment flexibility following bifurcation and exposure to T-cycles, mice in Study 1 were repeatedly phase-shifted. Mice from experimental conditions rapidly phase-shifted their activity, while control mice showed expected transient misalignment. In Study 2 and 3, mice followed a several weeks-long intervention designed to model a modified DuPont or Continental shiftwork schedule, respectively. For both schedules, bifurcation and nocturnal dim lighting reduced circadian misalignment. Together, these studies demonstrate proof of concept that mammalian circadian systems can be rendered sufficiently flexible to adapt to multiple, rapidly changing shiftwork schedules. Flexible adaptation to exotic light-dark cycles likely relies on entrainment mechanisms that are distinct from traditional entrainment.
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ISSN (up) 2624-5175 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2661
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Author Aarts, M.P.J.; Hartmeyer, S.L.; Morsink, K.; Kort, H.S.M.; de Kort, Y.A.W.
Title Can Special Light Glasses Reduce Sleepiness and Improve Sleep of Nightshift Workers? A Placebo-Controlled Explorative Field Study Type Journal Article
Year 2020 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep
Volume 2 Issue 2 Pages 225-245
Keywords Human Health
Abstract Nightshift workers go against the natural sleep–wake rhythm. Light can shift the circadian clock but can also induce acute alertness. This placebo-controlled exploratory field study examined the effectiveness of light glasses to improve alertness while reducing the sleep complaints of hospital nurses working nightshifts. In a crossover within-subjects design, 23 nurses participated, using treatment glasses and placebo glasses. Sleepiness and sleep parameters were measured. A linear mixed model analysis on sleepiness revealed no significant main effect of the light intervention. An interaction effect was found indicating that under the placebo condition, sleepiness was significantly higher on the first nightshift than on the last night, while under the treatment condition, sleepiness remained stable across nightshift sessions. Sleepiness during the commute home also showed a significant interaction effect, demonstrating that after the first nightshift, driver sleepiness was higher for placebo than for treatment. Subjective sleep quality showed a negative main effect of treatment vs. placebo, particularly after the first nightshift. In retrospect, both types of light glasses were self-rated as effective. The use of light glasses during the nightshift may help to reduce driver sleepiness during the commute home, which is relevant, as all participants drove home by car or (motor) bike.
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ISSN (up) 2624-5175 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2977
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Author Panagiotou, M.; Rohling, J.H.T.; Deboer, T.
Title Sleep Network Deterioration as a Function of Dim-Light-At-Night Exposure Duration in a Mouse Model Type Journal Article
Year 2020 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep
Volume 2 Issue 3 Pages 308-324
Keywords Animals
Abstract Artificial light, despite its widespread and valuable use, has been associated withdeterioration of health and well-being, including altered circadian timing and sleep disturbances,particularly in nocturnal exposure. Recent findings from our lab reveal significant sleep andsleep electroencephalogram (EEG) changes owing to three months exposure to dim-light-at-night(DLAN). Aiming to further explore the detrimental effects of DLAN exposure, in the present study,we continuously recorded sleep EEG and the electromyogram for baseline 24-h and following 6-h sleepdeprivation in a varied DLAN duration scheme. C57BL/6J mice were exposed to a 12:12 h light:DLANcycle (75lux:5lux) vs. a 12:12 h light:dark cycle (75lux:0lux) for one day, one week, and one month.Our results show that sleep was already affected by a mere day of DLAN exposure with additionalcomplications emerging with increasing DLAN exposure duration, such as the gradual delay ofthe daily 24-h vigilance state rhythms. We conducted detrended fluctuation analysis (DFA) on thelocomotor activity data following 1-month and 3-month DLAN exposure, and a significantly lesshealthy rest-activity pattern, based on the decreased alpha values, was found in both conditionscompared to the control light-dark. Taking into account the behavioral, sleep and the sleep EEGparameters, our data suggest that DLAN exposure, even in the shortest duration, induces deleteriouseffects; nevertheless, potential compensatory mechanisms render the organism partly adjustable andable to cope. We think that, for this reason, our data do not always depict linear divergence amonggroups, as compared with control conditions. Chronic DLAN exposure impacts the sleep regulatorysystem, but also brain integrity, diminishing its adaptability and reactivity, especially apparent in thesleep EEG alterations and particular low alpha values following DFA.
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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 (up) 2624-5175 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 3078
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