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Author Juda, M.; Liu-Ambrose, T.; Feldman, F.; Suvagau, C.; Mistlberger, R.E. url  doi
openurl 
  Title Light in the Senior Home: Effects of Dynamic and Individual Light Exposure on Sleep, Cognition, and Well-Being Type Journal Article
  Year 2020 Publication Clocks & Sleep Abbreviated Journal Clocks Sleep  
  Volume (down) 2 Issue 4 Pages 557-576  
  Keywords Human health; aging; circadian rhythms; cognition; entrainment; light; nursing home; sleep  
  Abstract Disrupted sleep is common among nursing home patients and is associated with cognitive decline and reduced well-being. Sleep disruptions may in part be a result of insufficient daytime light exposure. This pilot study examined the effects of dynamic “circadian” lighting and individual light exposure on sleep, cognitive performance, and well-being in a sample of 14 senior home residents. The study was conducted as a within-subject study design over five weeks of circadian lighting and five weeks of conventional lighting, in a counterbalanced order. Participants wore wrist accelerometers to track rest-activity and light profiles and completed cognitive batteries (National Institute of Health (NIH) toolbox) and questionnaires (depression, fatigue, sleep quality, lighting appraisal) in each condition. We found no significant differences in outcome variables between the two lighting conditions. Individual differences in overall (indoors and outdoors) light exposure levels varied greatly between participants but did not differ between lighting conditions, except at night (22:00-6:00), with maximum light exposure being greater in the conventional lighting condition. Pooled data from both conditions showed that participants with higher overall morning light exposure (6:00-12:00) had less fragmented and more stable rest-activity rhythms with higher relative amplitude. Rest-activity rhythm fragmentation and long sleep duration both uniquely predicted lower cognitive performance.  
  Address Sleep and Circadian Neuroscience Laboratory, Department of Psychology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada  
  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 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:33327499; PMCID:PMC7768397 Approved no  
  Call Number GFZ @ kyba @ Serial 3261  
Permanent link to this record
 

 
Author Akacem, L.D.; Wright, K.P.J.; LeBourgeois, M.K. url  doi
openurl 
  Title Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study Type Journal Article
  Year 2016 Publication Neurobiology of Sleep and Circadian Rhythms Abbreviated Journal Neurobiol Sleep Circadian Rhythms  
  Volume (down) 1 Issue 2 Pages 27-31  
  Keywords Human Health  
  Abstract Light exposure and sleep timing are two factors that influence inter-individual variability in the timing of the human circadian clock. The aim of this study was to quantify the degree to which evening light exposure predicts variance in circadian timing over and above bedtime alone in preschool children. Participants were 21 children ages 4.5-5.0 years (4.7 +/- 0.2 years; 9 females). Children followed their typical sleep schedules for 4 days during which time they wore a wrist actigraph to assess sleep timing and a pendant light meter to measure minute-by-minute illuminance levels in lux. On the 5th day, children participated in an in-home dim-light melatonin onset (DLMO) assessment. Light exposure in the 2 h before bedtime was averaged and aggregated across the 4 nights preceding the DLMO assessment. Mean DLMO and bedtime were 19:22 +/- 01:04 and 20:07 +/- 00:46, respectively. Average evening light exposure was 710.1 +/- 1418.2 lux. Children with later bedtimes (lights-off time) had more delayed melatonin onset times (r=0.61, p=0.002). Evening light exposure was not independently associated with DLMO (r=0.32, p=0.08); however, a partial correlation between evening light exposure and DLMO when controlling for bedtime yielded a positive correlation (r=0.46, p=0.02). Bedtime explained 37.3% of the variance in the timing of DLMO, and evening light exposure accounted for an additional 13.3% of the variance. These findings represent an important step in understanding factors that influence circadian phase in preschool-age children and have implications for understanding a modifiable pathway that may underlie late sleep timing and the development of evening settling problems in early childhood.  
  Address Sleep and Development Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2451-9944 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:28042611; PMCID:PMC5193478 Approved no  
  Call Number LoNNe @ kyba @ Serial 1755  
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Author Lowden, A.; Lemos, N.; Gonçalves, B.; Öztürk, G.; Louzada, F.; Pedrazzoli, M.; Moreno, C. url  doi
openurl 
  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 (down) 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.  
  Address  
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  ISSN 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2137  
Permanent link to this record
 

 
Author Prayag, A.; Münch, M.; Aeschbach, D.; Chellappa, S.; Gronfier, C. url  doi
openurl 
  Title Light Modulation of Human Clocks, Wake, and Sleep Type Journal Article
  Year 2019 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep  
  Volume (down) 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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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2266  
Permanent link to this record
 

 
Author Walbeek, T.J.; Harrison, E.M.; Soler, R.R.; Gorman, M.R. url  doi
openurl 
  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 (down) 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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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2661  
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