| Records |
Author  |
Boivin, D.B.; Boudreau, P.; Tremblay, G.M. |
| Title |
Phototherapy and orange-tinted goggles for night-shift adaptation of police officers on patrol |
Type |
Journal Article |
| Year |
2012 |
Publication |
Chronobiology International |
Abbreviated Journal |
Chronobiol Int |
| Volume |
29 |
Issue |
5 |
Pages |
629-640 |
| Keywords |
Human Health; Adaptation, Physiological/*physiology; Adult; Attention/physiology; Circadian Rhythm/physiology; Color; Darkness; *Eye Protective Devices/adverse effects; Female; Humans; Light; Male; Melatonin/analogs & derivatives/metabolism/urine; Phototherapy/*adverse effects; *Police; Psychomotor Performance/*physiology; Saliva/chemistry; Sleep/physiology; Work Schedule Tolerance/*physiology |
| Abstract |
The aim of the present combined field and laboratory study was to assess circadian entrainment in two groups of police officers working seven consecutive 8/8.5-h night shifts as part of a rotating schedule. Eight full-time police officers on patrol (mean age +/- SD: 29.8 +/- 6.5 yrs) were provided an intervention consisting of intermittent exposure to wide-spectrum bright light at night, orange-tinted goggles at sunrise, and maintenance of a regular sleep/darkness episode in the day. Orange-tinted goggles have been shown to block the melatonin-suppressing effect of light significantly more than neutral gray density goggles. Nine control group police officers (mean age +/- SD: 30.3 +/- 4.1 yrs) working the same schedule were enrolled. Police officers were studied before, after (in the laboratory), and during (ambulatory) a series of seven consecutive nights. Urine samples were collected at wake time and bedtime throughout the week of night work and during laboratory visits (1 x /3 h) preceding and following the work week to measure urinary 6-sulfatoxymelatonin (UaMT6s) excretion rate. Subjective alertness was assessed at the start, middle, and end of night shifts. A 10-min psychomotor vigilance task was performed at the start and end of each shift. Both laboratory visits consisted of two 8-h sleep episodes based on the prior schedule. Saliva samples were collected 2 x /h during waking episodes to assay their melatonin content. Subjective alertness (3 x /h) and performance (1 x /2 h) were assessed during wake periods in the laboratory. A mixed linear model was used to analyze the progression of UaMt6s excreted during daytime sleep episodes at home, as well as psychomotor performance and subjective alertness during night shifts. Two-way analysis of variance (ANOVA) (factors: laboratory visit and group) were used to compare peak salivary melatonin and UaMT6s excretion rate in the laboratory. In both groups of police officers, the excretion rate of UaMT6s at home was higher during daytime sleep episodes at the end compared to the start of the work week (p < .001). This rate increased significantly more in the intervention than control group (p = .032). A significant phase delay of salivary melatonin was observed in both groups at the end of study (p = .009), although no significant between-group difference was reached. Reaction speed dropped, and subjective alertness decreased throughout the night shift in both groups (p < .001). Reaction speed decreased throughout the work week in the control group (p </= .021), whereas no difference was observed in the intervention group. Median reaction time was increased as of the 5th and 6th nights compared to the 2nd night in controls (p </= .003), whereas it remained stable in the intervention group. These observations indicate better physiological adaptation in the intervention group compared to the controls. |
| 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 |
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| Language |
English |
Summary Language |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0742-0528 |
ISBN |
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| Notes |
PMID:22621360 |
Approved |
no |
| Call Number |
LoNNe @ christopher.kyba @ |
Serial |
509 |
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| Author |
Boivin, D.B.; Duffy, J.F.; Kronauer, R.E.; Czeisler, C.A. |
| Title |
Dose-response relationships for resetting of human circadian clock by light |
Type |
Journal Article |
| Year |
1996 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
379 |
Issue |
6565 |
Pages |
540-542 |
| Keywords |
Human Health; Adult; Body Temperature; Circadian Rhythm/*radiation effects; Dose-Response Relationship, Radiation; Humans; *Light; Male; NASA Discipline Number 18-10; NASA Discipline Regulatory Physiology; NASA Program Space Physiology and Countermeasures; Non-NASA Center |
| Abstract |
Since the first report in unicells, studies across diverse species have demonstrated that light is a powerful synchronizer which resets, in an intensity-dependent manner, endogenous circadian pacemakers. Although it is recognized that bright light (approximately 7,000 to 13,000 lux) is an effective circadian synchronizer in humans, it is widely believed that the human circadian pacemaker is insensitive to ordinary indoor illumination (approximately 50-300 lux). It has been proposed that the relationship between the resetting effect of light and its intensity follows a compressive nonlinear function, such that exposure to lower illuminances still exerts a robust effect. We therefore undertook a series of experiments which support this hypothesis and report here that light of even relatively low intensity (approximately 180 lux) significantly phase-shifts the human circadian pacemaker. Our results clearly demonstrate that humans are much more sensitive to light than initially suspected and support the conclusion that they are not qualitatively different from other mammals in their mechanism of circadian entrainment. |
| Address |
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA |
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English |
Summary Language |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:8596632 |
Approved |
no |
| Call Number |
LoNNe @ kagoburian @ |
Serial |
722 |
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| Author |
Brainard, G.C.; Sliney, D.; Hanifin, J.P.; Glickman, G.; Byrne, B.; Greeson, J.M.; Jasser, S.; Gerner, E.; Rollag, M.D. |
| Title |
Sensitivity of the human circadian system to short-wavelength (420-nm) light |
Type |
Journal Article |
| Year |
2008 |
Publication |
Journal of Biological Rhythms |
Abbreviated Journal |
J Biol Rhythms |
| Volume |
23 |
Issue |
5 |
Pages |
379-386 |
| Keywords |
Human Health; Adult; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Male; Melatonin/metabolism; Models, Biological; Neurosecretory Systems; Photons; Pineal Gland/metabolism; Retinal Ganglion Cells/*metabolism; Vision, Ocular |
| Abstract |
The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment melanopsin. Nine action spectrum studies using rodents, monkeys, and humans for these responses indicate peak sensitivities in the blue region of the visible spectrum ranging from 459 to 484 nm, with some disagreement in short-wavelength sensitivity of the spectrum. The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression. Adult female (n=14) and male (n=12) subjects participated in 2 studies, each employing a within-subjects design. In a fluence-response study, subjects (n=8) were tested with 8 light irradiances at 420 nm ranging over a 4-log unit photon density range of 10(10) to 10(14) photons/cm(2)/sec and 1 dark exposure control night. In the other study, subjects (n=18) completed an experiment comparing melatonin suppression with equal photon doses (1.21 x 10(13) photons/cm(2)/sec) of 420 nm and 460 nm monochromatic light and a dark exposure control night. The first study demonstrated a clear fluence-response relationship between 420-nm light and melatonin suppression (p<0.001) with a half-saturation constant of 2.74 x 10(11) photons/cm(2)/sec. The second study showed that 460-nm light is significantly stronger than 420-nm light for suppressing melatonin (p<0.04). Together, the results clarify the visible short-wavelength sensitivity of the human melatonin suppression action spectrum. This basic physiological finding may be useful for optimizing lighting for therapeutic and other applications. |
| Address |
Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA. george.brainard@jefferson.edu |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0748-7304 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:18838601 |
Approved |
no |
| Call Number |
LoNNe @ kagoburian @ |
Serial |
724 |
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| Author |
Bullough, J.D.; Rea, M.S.; Figueiro, M.G. |
| Title |
Of mice and women: light as a circadian stimulus in breast cancer research |
Type |
Journal Article |
| Year |
2006 |
Publication |
Cancer Causes & Control : CCC |
Abbreviated Journal |
Cancer Causes Control |
| Volume |
17 |
Issue |
4 |
Pages |
375-383 |
| Keywords |
Human Health; Animals; Breast Neoplasms/*physiopathology; *Circadian Rhythm; *Disease Models, Animal; Female; Humans; *Light; Light Signal Transduction; Mammary Neoplasms, Animal/*physiopathology; Melatonin/metabolism; Mice; Muridae/metabolism |
| Abstract |
OBJECTIVE: Nocturnal rodents are frequently used as models in human breast cancer research, but these species have very different visual and circadian systems and, therefore, very different responses to optical radiation or, informally, light. Because of the impact of light on the circadian system and because recent evidence suggests that cancer risk might be related to circadian disruption, it is becoming increasingly clear that optical radiation must be properly characterized for both nocturnal rodents and diurnal humans to make significant progress in unraveling links between circadian disruption and breast cancer. In this paper, we propose a quantitative framework for comparing radiometric and photometric quantities in human and rodent studies. METHODS: We reviewed published research on light as a circadian stimulus for humans and rodents. Both suppression of nocturnal melatonin and phase shifting were examined as outcome measures for the circadian system. RESULTS: The data were used to develop quantitative comparisons regarding the absolute and spectral sensitivity for the circadian systems of humans and nocturnal rodents. CONCLUSIONS: Two models of circadian phototransduction, for mouse and humans, have been published providing spectral sensitivities for these two species. Despite some methodological variations among the studies reviewed, the circadian systems of nocturnal rodents are approximately 10,000 times more sensitive to optical radiation than that of humans. Circadian effectiveness of different sources for both humans and nocturnal rodents are offered together with a scale relating their absolute sensitivities. Instruments calibrated in terms of conventional photometric units (e.g., lux) will not accurately characterize the circadian stimulus for either humans or rodents. |
| Address |
Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA. bulloj@rpi.edu |
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Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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0957-5243 |
ISBN |
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| Notes |
PMID:16596289 |
Approved |
no |
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LoNNe @ kagoburian @ |
Serial |
726 |
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| Author |
Cajochen, C.; Altanay-Ekici, S.; Munch, M.; Frey, S.; Knoblauch, V.; Wirz-Justice, A. |
| Title |
Evidence that the lunar cycle influences human sleep |
Type |
Journal Article |
| Year |
2013 |
Publication |
Current Biology : CB |
Abbreviated Journal |
Curr Biol |
| Volume |
23 |
Issue |
15 |
Pages |
1485-1488 |
| Keywords |
Adult; Aged; Cross-Sectional Studies; Electroencephalography; Female; Humans; Hydrocortisone/analysis/metabolism; Male; Melatonin/analysis/metabolism; Middle Aged; Moon; Nontherapeutic Human Experimentation; Periodicity; Saliva/metabolism; Sleep/*physiology; Sleep Stages/physiology; Young Adult |
| Abstract |
Endogenous rhythms of circalunar periodicity ( approximately 29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species [1, 2]. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior [3]. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues. |
| Address |
Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4012 Basel, Switzerland. christian.cajochen@upkbs.ch |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0960-9822 |
ISBN |
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Expedition |
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Conference |
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| Notes |
PMID:23891110 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
140 |
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