| Records |
| 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 |
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English |
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| ISSN |
0161-8105 |
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| Notes |
PMID:23904684; PMCID:PMC3700721 |
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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 |
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English |
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Edition |
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| ISSN |
1528-4042 |
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| Notes |
PMID:22322663 |
Approved |
no |
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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. |
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Edition |
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| ISSN |
1477-1535 |
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no |
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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 |
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English |
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Edition |
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| ISSN |
0742-0528 |
ISBN |
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| Notes |
PMID:22621361 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
148 |
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| Author |
Smith, M.R.; Eastman, C.I. |
| Title |
Shift work: health, performance and safety problems, traditional countermeasures, and innovative management strategies to reduce circadian misalignment |
Type |
Journal Article |
| Year |
2012 |
Publication |
Nature and Science of Sleep |
Abbreviated Journal |
Nat Sci Sleep |
| Volume |
4 |
Issue |
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Pages |
111-132 |
| Keywords |
bright light; circadian rhythms; melatonin; night work; phase-shifting; sleep |
| Abstract |
There are three mechanisms that may contribute to the health, performance, and safety problems associated with night-shift work: (1) circadian misalignment between the internal circadian clock and activities such as work, sleep, and eating, (2) chronic, partial sleep deprivation, and (3) melatonin suppression by light at night. The typical countermeasures, such as caffeine, naps, and melatonin (for its sleep-promoting effect), along with education about sleep and circadian rhythms, are the components of most fatigue risk-management plans. We contend that these, while better than nothing, are not enough because they do not address the underlying cause of the problems, which is circadian misalignment. We explain how to reset (phase-shift) the circadian clock to partially align with the night-work, day-sleep schedule, and thus reduce circadian misalignment while preserving sleep and functioning on days off. This involves controlling light and dark using outdoor light exposure, sunglasses, sleep in the dark, and a little bright light during night work. We present a diagram of a sleep-and-light schedule to reduce circadian misalignment in permanent night work, or a rotation between evenings and nights, and give practical advice on how to implement this type of plan. |
| Address |
Biological Rhythms Research Laboratory, Rush University Medical Center, Chicago, IL, USA |
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English |
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1179-1608 |
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| Notes |
PMID:23620685; PMCID:PMC3630978 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
149 |
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