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Author Boivin, D.B.; Boudreau, P.; James, F.O.; Kin, N.M.K.N.Y.
Title Photic resetting in night-shift work: impact on nurses' sleep Type Journal Article
Year 2012 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 29 Issue 5 Pages 619-628
Keywords Adaptation, Physiological; Adult; *Circadian Rhythm; *Darkness; Female; Humans; *Light; Male; Melatonin/metabolism; Middle Aged; *Nurses; Sleep/*physiology; Work Schedule Tolerance/*physiology
Abstract The objective of this study was to quantify daytime sleep in night-shift workers with and without an intervention designed to recover the normal relationship between the endogenous circadian pacemaker and the sleep/wake cycle. Workers of the treatment group received intermittent exposure to full-spectrum bright light during night shifts and wore dark goggles during the morning commute home. All workers maintained stable 8-h daytime sleep/darkness schedules. The authors found that workers of the treatment group had daytime sleep episodes that lasted 7.1 +/- .1 h (mean +/- SEM) versus 6.6 +/- .2 h for workers in the control group (p = .04). The increase in total sleep time co-occurred with a larger proportion of the melatonin secretory episode during daytime sleep in workers of the treatment group. The results of this study showed reestablishment of a phase angle that is comparable to that observed on a day-oriented schedule favors longer daytime sleep episodes in night-shift workers. (Author correspondence: diane.boivin@douglas.mcgill.ca ).
Address Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Quebec, Canada. diane.boivin@douglas.mcgill.ca
Corporate Author (down) 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:22621359 Approved no
Call Number IDA @ john @ Serial 144
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Author Chang, A.-M.; Scheer, F.A.J.L.; Czeisler, C.A.; Aeschbach, D.
Title Direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans depend on prior light history Type Journal Article
Year 2013 Publication Sleep Abbreviated Journal Sleep
Volume 36 Issue 8 Pages 1239-1246
Keywords Arousal/*radiation effects; Attention/radiation effects; Cross-Over Studies; *Electroencephalography; Female; Humans; *Light; Male; Melatonin/blood/physiology; Psychomotor Performance/radiation effects; Reaction Time; Wakefulness/*radiation effects; Young Adult; Light history; alertness and performance; light exposure
Abstract STUDY OBJECTIVES: Light can induce an acute alerting response in humans; however, it is unknown whether the magnitude of this response is simply a function of the absolute illuminance of the light itself, or whether it depends on illuminance history preceding the stimulus. Here, we compared the effects of illuminance history on the alerting response to a subsequent light stimulus. DESIGN: A randomized, crossover design was used to compare the effect of two illuminance histories (1 lux vs. 90 lux) on the alerting response to a 6.5-h 90-lux light stimulus during the biological night. SETTING: Intensive Physiologic Monitoring Unit, Brigham and Women's Hospital, Boston, MA. PARTICIPANTS: Fourteen healthy young adults (6 F; 23.5 +/- 2.9 years). INTERVENTIONS: Participants were administered two 6.5-h light exposures (LE) of 90 lux during the biological night. For 3 days prior to each LE, participants were exposed to either 1 lux or 90 lux during the wake episode. MEASUREMENTS AND RESULTS: The alerting response to light was assessed using subjective sleepiness ratings, lapses of attention, and reaction times as measured with an auditory psychomotor vigilance task, as well as power density in the delta/theta range of the waking EEG. The alerting response to light was greater and lasted longer when the LE followed exposure to 1 lux compared to 90 lux light. CONCLUSION: The magnitude and duration of the alerting effect of light at night depends on the illuminance history and appears to be subject to sensitization and adaptation.
Address Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. amchang@rics.bwh.harvard.edu
Corporate Author (down) 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 0161-8105 ISBN Medium
Area Expedition Conference
Notes PMID:23904684; PMCID:PMC3700721 Approved no
Call Number IDA @ john @ Serial 145
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Author Karatsoreos, I.N.
Title Effects of circadian disruption on mental and physical health Type Journal Article
Year 2012 Publication Current Neurology and Neuroscience Reports Abbreviated Journal Curr Neurol Neurosci Rep
Volume 12 Issue 2 Pages 218-225
Keywords Chronobiology Disorders/*complications/genetics; Circadian Clocks/genetics; Cognition Disorders/*etiology/genetics; Humans; Metabolic Diseases/*etiology/genetics; Obesity/*etiology/genetics
Abstract Circadian (daily) rhythms in physiology and behavior are phylogenetically ancient and are present in almost all plants and animals. In mammals, these rhythms are generated by a master circadian clock in the suprachiasmatic nucleus of the hypothalamus, which in turn synchronizes “peripheral oscillators” throughout the brain and body in almost all cell types and organ systems. Although circadian rhythms are phylogenetically ancient, modern industrialized society and the ubiquity of electric lighting has resulted in a fundamental alteration in the relationship between an individual's endogenous circadian rhythmicity and the external environment. The ramifications of this desynchronization for mental and physical health are not fully understood, although numerous lines of evidence are emerging that link defects in circadian timing with negative health outcomes. This article explores the function of the circadian system, the effects of disrupted clocks on the brain and body, and how these effects impact mental and physical health.
Address Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, 205 Wegner Hall, Pullman, WA 99164, USA. iliak@vetmed.wsu.edu
Corporate Author (down) 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 1528-4042 ISBN Medium
Area Expedition Conference
Notes PMID:22322663 Approved no
Call Number IDA @ john @ Serial 146
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Author Kretschmer, V.; Schmidt, K.-H.; Griefahn, B.
Title Bright light effects on working memory, sustained attention and concentration of elderly night shift workers Type Journal Article
Year 2012 Publication Lighting Research and Technology Abbreviated Journal Lighting Research and Technology
Volume 44 Issue 3 Pages 316-333
Keywords shift work; light at night; light exposure; memory; concentration; human health
Abstract Night shift workers show a decline in performance during working time. Due to demographic change, the labour market requires more elderly people to work at night. Ageing is accompanied by a decrease in cognitive abilities, in the capabilities of the visual system and in coping with night work from the age of 40 onwards. This investigation focuses on the effects of bright light exposure on the working memory, concentration and sustained attention of elderly persons during three consecutive night shifts. After statistical control for neuroticism and intelligence as covariates, the results demonstrate that exposure to bright light at night reduces error rates for a working memory task and a concentration performance task but performance on a sustained attention task is completely unaffected.
Address
Corporate Author (down) Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 147
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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 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 (down) 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
Permanent link to this record