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Author Lowden, A.; Akerstedt, T.
Title Assessment of a new dynamic light regimen in a nuclear power control room without windows on quickly rotating shiftworkers--effects on health, wakefulness, and circadian alignment: a pilot study Type Journal Article
Year 2012 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 29 Issue 5 Pages 641-649
Keywords (up) Adaptation, Physiological; Adult; *Circadian Rhythm; Darkness/adverse effects; *Environment, Controlled; Female; Humans; *Light; Male; Melatonin/metabolism; Middle Aged; Photic Stimulation; Pilot Projects; Saliva/chemistry; Sleep/*physiology; *Wakefulness; *Work Schedule Tolerance
Abstract The aim of the study was to test whether a new dynamic light regime would improve alertness, sleep, and adaptation to rotating shiftwork. The illumination level in a control room without windows at a nuclear power station was ~200 lux (straight-forward horizontal gaze) using a weak yellow light of 200 lux, 3000 K (Philips Master TLD 36 W 830). New lighting equipment was installed in one area of the control room above the positions of the reactor operators. The new lights were shielded from the control group by a distance of >6 m, and the other operators worked at desks turned away from the new light. The new lights were designed to give three different light exposures: (i) white/blue strong light of 745 lux, 6000 K; (ii) weak yellow light of 650 lux, 4000 K; and (iii) yellow moderate light of 700 lux, 4000 K. In a crossover design, the normal and new light exposures were given during a sequence of three night shifts, two free days, two morning shifts, and one afternoon shift (NNN + MMA), with 7 wks between sessions. The operators consisted of two groups; seven reactor operators from seven work teams were at one time exposed to the new equipment and 16 other operators were used as controls. The study was conducted during winter with reduced opportunities of daylight exposure during work, after night work, or before morning work. Operators wore actigraphs, filled in a sleep/wake diary, including ratings of sleepiness on the Karolinska Sleepiness Scale (KSS) every 2 h, and provided saliva samples for analysis of melatonin at work (every 2nd h during one night shift and first 3 h during one morning shift). Results from the wake/sleep diary showed the new light treatment increased alertness during the 2nd night shift (interaction group x light x time, p < .01). Time of waking was delayed in the light condition after the 3rd night shift (group x light, p < .05), but the amount of wake time during the sleep span increased after the 2nd night shift (p < .05), also showing a tendency to affect sleep efficiency (p < .10). Effects on circadian phase were difficult to establish given the small sample size and infrequent sampling of saliva melatonin. Nonetheless, it seems that appropriate dynamic light in rooms without windows during the dark Nordic season may promote alertness, sleep, and better adaptation to quickly rotating shiftwork.
Address Stress Research Institute, Stockholm University, Stockholm, Sweden. arne.lowden@stress.su.se
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 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:22621361 Approved no
Call Number IDA @ john @ Serial 148
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Author Sasseville, A.; Benhaberou-Brun, D.; Fontaine, C.; Charon, M.-C.; Hebert, M.
Title Wearing blue-blockers in the morning could improve sleep of workers on a permanent night schedule: a pilot study Type Journal Article
Year 2009 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 26 Issue 5 Pages 913-925
Keywords (up) Adaptation, Physiological; Adult; Biological Clocks; Circadian Rhythm; Female; Humans; *Light; Male; Middle Aged; Photoperiod; Pilot Projects; Seasons; *Sleep; Wakefulness; *Work Schedule Tolerance; shift work; blue light; blue blocker; light therapy
Abstract Night shiftworkers often complain of disturbed sleep during the day. This could be partly caused by morning sunlight exposure during the commute home, which tends to maintain the circadian clock on a daytime rhythm. The circadian clock is most sensitive to the blue portion of the visible spectrum, so our aim was to determine if blocking short wavelengths of light below 540 nm could improve daytime sleep quality and nighttime vigilance of night shiftworkers. Eight permanent night shiftworkers (32-56 yrs of age) of Quebec City's Canada Post distribution center were evaluated during summertime, and twenty others (24-55 yrs of age) during fall and winter. Timing, efficacy, and fragmentation of daytime sleep were analyzed over four weeks by a wrist activity monitor, and subjective vigilance was additionally assessed at the end of the night shift in the fall-winter group. The first two weeks served as baseline and the remaining two as experimental weeks when workers had to wear blue-blockers glasses, either just before leaving the workplace at the end of their shift (summer group) or 2 h before the end of the night shift (fall-winter group). They all had to wear the glasses when outside during the day until 16:00 h. When wearing the glasses, workers slept, on average +/-SD, 32+/-29 and 34+/-60 more min/day, increased their sleep efficacy by 1.95+/-2.17% and 4.56+/-6.1%, and lowered their sleep fragmentation by 1.74+/-1.36% and 4.22+/-9.16% in the summer and fall-winter group, respectively. Subjective vigilance also generally improved on Fridays in the fall-winter group. Blue-blockers seem to improve daytime sleep of permanent night-shift workers.
Address Centre de Recherche Universite Laval Robert-Giffard/Department of Oto Rhino Laryngology and Ophtalmology, Universite Laval, Quebec, 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 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:19637050 Approved no
Call Number IDA @ john @ Serial 295
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Author Chaves, I.; Pokorny, R.; Byrdin, M.; Hoang, N.; Ritz, T.; Brettel, K.; Essen, L.-O.; van der Horst, G.T.J.; Batschauer, A.; Ahmad, M.
Title The cryptochromes: blue light photoreceptors in plants and animals Type Journal Article
Year 2011 Publication Annual Review of Plant Biology Abbreviated Journal Annu Rev Plant Biol
Volume 62 Issue Pages 335-364
Keywords (up) Adenosine Triphosphate/metabolism; Animals; Cryptochromes/chemistry/classification/*physiology; DNA Repair; Deoxyribodipyrimidine Photo-Lyase/chemistry/classification/physiology; Homing Behavior; Insects/physiology; *Light Signal Transduction; Magnetics; Mice; Oxidation-Reduction; Phosphorylation/physiology; Plants/*metabolism; blue light
Abstract Cryptochromes are flavoprotein photoreceptors first identified in Arabidopsis thaliana, where they play key roles in growth and development. Subsequently identified in prokaryotes, archaea, and many eukaryotes, cryptochromes function in the animal circadian clock and are proposed as magnetoreceptors in migratory birds. Cryptochromes are closely structurally related to photolyases, evolutionarily ancient flavoproteins that catalyze light-dependent DNA repair. Here, we review the structural, photochemical, and molecular properties of cry-DASH, plant, and animal cryptochromes in relation to biological signaling mechanisms and uncover common features that may contribute to better understanding the function of cryptochromes in diverse systems including in man.
Address Department of Genetics, Erasmus University Medical Center, 3000 CA Rotterdam, The Netherlands. i.chaves@erasmusmc.nl
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 1543-5008 ISBN Medium
Area Expedition Conference
Notes PMID:21526969 Approved no
Call Number IDA @ john @ Serial 341
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Author Fonken, L.K.; Lieberman, R.A.; Weil, Z.M.; Nelson, R.J.
Title Dim light at night exaggerates weight gain and inflammation associated with a high-fat diet in male mice Type Journal Article
Year 2013 Publication Endocrinology Abbreviated Journal Endocrinology
Volume 154 Issue 10 Pages 3817-3825
Keywords (up) Adipose Tissue, White/*immunology/metabolism/pathology; Animals; Antigens, CD11b/biosynthesis/genetics/metabolism; Appetite Regulation/*radiation effects; Arcuate Nucleus/*immunology/metabolism/pathology; Behavior, Animal/radiation effects; Circadian Rhythm; Cytokines/biosynthesis/genetics/metabolism; Diet, High-Fat/*adverse effects; Feeding Behavior/radiation effects; Gene Expression Regulation; Glucose Intolerance/etiology/immunology/metabolism/pathology; I-kappa B Kinase/biosynthesis/genetics/metabolism; Insulin Resistance; Lighting/*adverse effects; Male; Mice; Microglia/immunology/metabolism/pathology; Nerve Tissue Proteins/biosynthesis/genetics/metabolism; Obesity/*etiology/immunology/metabolism/pathology; Random Allocation; *Weight Gain
Abstract Elevated nighttime light exposure is associated with symptoms of metabolic syndrome. In industrialized societies, high-fat diet (HFD) and exposure to light at night (LAN) often cooccur and may contribute to the increasing obesity epidemic. Thus, we hypothesized that dim LAN (dLAN) would provoke additional and sustained body mass gain in mice on a HFD. Male mice were housed in either a standard light/dark cycle or dLAN and fed either chow or HFD. Exposure to dLAN and HFD increase weight gain, reduce glucose tolerance, and alter insulin secretion as compared with light/dark cycle and chow, respectively. The effects of dLAN and HFD appear additive, because mice exposed to dLAN that were fed HFD display the greatest increases in body mass. Exposure to both dLAN and HFD also change the timing of food intake and increase TNFalpha and MAC1 gene expression in white adipose tissue after 4 experimental weeks. Changes in MAC1 gene expression occur more rapidly due to HFD as compared with dLAN; after 5 days of experimental conditions, mice fed HFD already increase MAC1 gene expression in white adipose tissue. HFD also elevates microglia activation in the arcuate nucleus of the hypothalamus and hypothalamic TNFalpha, IL-6, and Ikbkb gene expression. Microglia activation is increased by dLAN, but only among chow-fed mice and dLAN does not affect inflammatory gene expression. These results suggest that dLAN exaggerates weight gain and peripheral inflammation associated with HFD.
Address Department of Neuroscience, Wexner Medical Center, The Ohio State University, 636 Biomedical Research Tower, 460 West 12th Avenue, Columbus, Ohio 43210. fonken.1@osu.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 0013-7227 ISBN Medium
Area Expedition Conference
Notes PMID:23861373 Approved no
Call Number IDA @ john @ Serial 93
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Author Vollmer, C.; Michel, U.; Randler, C.
Title Outdoor light at night (LAN) is correlated with eveningness in adolescents Type Journal Article
Year 2012 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 29 Issue 4 Pages 502-508
Keywords (up) Adolescent; *Adolescent Behavior/drug effects; Biological Clocks; Central Nervous System Stimulants/administration & dosage; *Circadian Rhythm/drug effects; Computers; Cross-Sectional Studies; Female; Germany; Humans; *Light; Lighting; Male; *Photic Stimulation; *Photoperiod; Questionnaires; *Sleep/drug effects; Television; Time Factors; Video Games; *Wakefulness/drug effects
Abstract External zeitgebers synchronize the human circadian rhythm of sleep and wakefulness. Humans adapt their chronotype to the day-night cycle, the strongest external zeitgeber. The human circadian rhythm shifts to evening-type orientation when daylight is prolonged into the evening and night hours by artificial light sources. Data from a survey of 1507 German adolescents covering questions about chronotype and electronic screen media use combined with nocturnal satellite image data suggest a relationship between chronotype and artificial nocturnal light. Adolescents living in brightly illuminated urban districts had a stronger evening-type orientation than adolescents living in darker and more rural municipalities. This result persisted when controlling for time use of electronic screen media, intake of stimulants, type of school, age, puberty status, time of sunrise, sex, and population density. Time spent on electronic screen media use-a source of indoor light at night-is also correlated with eveningness, as well as intake of stimulants, age, and puberty status, and, to a lesser degree, type of school and time of sunrise. Adequate urban development design and parents limiting adolescents' electronic screen media use in the evening could help to adjust adolescents' zeitgeber to early school schedules when they provide appropriate lighting conditions for daytime and for nighttime.
Address Department of Biology, University of Education Heidelberg, Germany. vollmer@ph-heidelberg.de
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 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:22214237 Approved no
Call Number IDA @ john @ Serial 150
Permanent link to this record