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Author Akacem, L.D.; Wright, K.P.J.; LeBourgeois, M.K.
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 1 Issue (up) 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
Publisher Place of Publication Editor
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 Kalousová, L.; Xiao, B.; Burgard, S.A.
Title Material hardship and sleep: results from the Michigan Recession and Recovery Study Type Journal Article
Year 2019 Publication Sleep Health Abbreviated Journal Sleep Health
Volume 5 Issue (up) 2 Pages 113-127
Keywords Human Health; Remote Sensing; Sleep; sleep inequality; Society; sleep outcomes
Abstract Objective

Sleep is unequally distributed in the US population. People with low socioeconomic status report worse quality and shorter sleep than people with high socioeconomic status. Past research hypothesized that a potential reason for this link could be exposure to material hardship. This study examines the associations between several material hardships and sleep outcomes.

Methods

We use population-representative cross-sectional data (n = 730) from the Michigan Recession and Recovery Study collected in 2013 and examine the associations between 6 indicators of material hardship (employment instability, financial problems, housing instability, food insecurity, forgone medical care, and the total number of material hardships reported) and 3 sleep outcomes (short sleep, sleep problems, and nonrestorative sleep). We build multivariable logistic regression models controlling for respondents’ characteristics and light pollution near their residence.

Results

In unadjusted models, all material hardships were associated with negative sleep outcomes. In adjusted models, forgone medical care was a statistically significant predictor of nonrestorative sleep (average marginal effect 0.16), as was employment instability (average marginal effect 0.12). The probability of sleep problems and nonrestorative sleep increased with a greater number of hardships overall (average marginal effects of .02 and .05, respectively). We found marginally statistically significant positive associations between food insecurity and short sleep and sleep problems.

Conclusions

This study finds that, except when considering foregone medical care, employment instability, and total count of material hardships, associations between material hardship and negative sleep outcomes are not statistically significant after adjusting for a robust set of sociodemographic and health characteristics.
Address Nuffield College, 1 New Rd, Oxford, OX1 1NF, United Kingdom; lucie.kalousova(at)nuffield.ox.ac.uk
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 2352-7218 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2180
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Author Smith, M.R.; Revell, V.L.; Eastman, C.I.
Title Phase advancing the human circadian clock with blue-enriched polychromatic light Type Journal Article
Year 2009 Publication Sleep Medicine Abbreviated Journal Sleep Med
Volume 10 Issue (up) 3 Pages 287-294
Keywords Adult; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Lighting/*methods; Male; Melatonin/metabolism; Phototherapy/*methods; Sleep; Wakefulness; Young Adult; blue light; sleep
Abstract BACKGROUND: Previous studies have shown that the human circadian system is maximally sensitive to short-wavelength (blue) light. Whether this sensitivity can be utilized to increase the size of phase shifts using light boxes and protocols designed for practical settings is not known. We assessed whether bright polychromatic lamps enriched in the short-wavelength portion of the visible light spectrum could produce larger phase advances than standard bright white lamps. METHODS: Twenty-two healthy young adults received either a bright white or bright blue-enriched 2-h phase advancing light pulse upon awakening on each of four treatment days. On the first treatment day the light pulse began 8h after the dim light melatonin onset (DLMO), on average about 2h before baseline wake time. On each subsequent day, light treatment began 1h earlier than the previous day, and the sleep schedule was also advanced. RESULTS: Phase advances of the DLMO for the blue-enriched (92+/-78 min, n=12) and white groups (76+/-45 min, n=10) were not significantly different. CONCLUSION: Bright blue-enriched polychromatic light is no more effective than standard bright light therapy for phase advancing circadian rhythms at commonly used therapeutic light levels.
Address Biological Rhythms Research Laboratory, Rush University Medical Center, Suite 425, 1645 W. Jackson Boulevard, Chicago, IL 60612, USA
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 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:18805055; PMCID:PMC2723863 Approved no
Call Number IDA @ john @ Serial 289
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Author Woods, H. C., & Scott, H.
Title Merging the Biological and Cognitive Processes of Sleep and Screens Type Journal Article
Year 2019 Publication Current Sleep Medicine Reports Abbreviated Journal
Volume 5 Issue (up) 3 Pages 150-155
Keywords Human Health
Abstract Purpose of Review

Screens are a permanent feature of life today and we have reached an interesting juncture with different research agendas investigating the biological and cognitive aspects of screen use separately. This review argues that it is timely and indeed essential that we bring together these research areas to fully understand both positive and negative aspects of screen use.

Recent Findings

More recent work is starting to take a more cohesive approach to understanding how device use pre-bedtime can impact our sleep by including both light and content in their experimental protocols which is a welcome development leading to a more nuanced understanding of both biological and cognitive processes.

Summary

We call for an open and collaborative approach to gain momentum in this direction of acknowledging both biological and cognitive factors enabling us to understand the relative impacts of both whilst using screens with regard to both light and content.
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 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ intern @ Serial 2640
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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 (up) 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.
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 2624-5175 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2661
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