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DLMO light at night

Evan D Chinoy, Michael P Harris, Min Ju Kim, Wei Wang, Jeanne F Duffy
OBJECTIVES: We tested whether a sleep and circadian-based treatment shown to improve circadian adaptation to night shifts and attenuate negative effects on alertness, performance and sleep in young adults would also be effective in older adults. METHODS: We assessed subjective alertness, sustained attention (psychomotor vigilance task, PVT), sleep duration (actigraphy) and circadian timing (salivary dim-light melatonin onset, DLMO) in 18 older adults (57.2±3.8 years; mean±SD) in a simulated shift work protocol...
August 25, 2016: Occupational and Environmental Medicine
Garth R Swanson, Annika Gorenz, Maliha Shaikh, Vishal Desai, Thomas Kaminsky, Jolice Van Den Berg, Terrence Murphy, Shohreh Raeisi, Louis Fogg, Martha Hotz Vitaterna, Christopher Forsyth, Fred Turek, Helen J Burgess, Ali Keshavarzian
Alcohol-induced intestinal hyperpermeability (AIHP) is a known risk factor for alcoholic liver disease (ALD), but only 20-30% of heavy alcoholics develop AIHP and ALD. The hypothesis of this study is that circadian misalignment would promote AIHP. We studied two groups of healthy subjects on a stable work schedule for 3 mo [day workers (DW) and night workers (NW)]. Subjects underwent two circadian phase assessments with sugar challenge to access intestinal permeability between which they drank 0.5 g/kg alcohol daily for 7 days...
July 1, 2016: American Journal of Physiology. Gastrointestinal and Liver Physiology
Shigekazu Higuchi, Sang-il Lee, Tomoaki Kozaki, Tetsuo Harada, Ikuo Tanaka
Light is the strongest synchronizer of human circadian rhythms, and exposure to residential light at night reportedly causes a delay of circadian rhythms. The present study was conducted to investigate the association between color temperature of light at home and circadian phase of salivary melatonin in adults and children. Twenty healthy children (mean age: 9.7 year) and 17 of their parents (mean age: 41.9 years) participated in the experiment. Circadian phase assessments were made with dim light melatonin onset (DLMO)...
2016: Chronobiology International
Tracey L Sletten, Ahuva Y Segal, Erin E Flynn-Evans, Steven W Lockley, Shantha M W Rajaratnam
Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M) aged 22.5 ± 3.1 (mean ± SD) years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission...
2015: PloS One
Marie Dumont, Jean Paquet
Decreased melatonin production, due to nighttime exposure to light, has been proposed as one of the physiological mechanisms increasing cancer risk in night workers. However, few studies measured melatonin production in night workers, and most of these studies did not measure melatonin over 24 h. One study compared total melatonin production between day and night shifts in rotating night workers and did not find significant differences. However, without baseline measures, it was not possible to exclude that melatonin production was reduced during both day and night work...
December 2014: Chronobiology International
Valentina Gumenyuk, Ryan Howard, Thomas Roth, Oleg Korzyukov, Christopher L Drake
STUDY OBJECTIVES: Permanent night-shift workers may develop shift-work disorder (SWD). In the current study, we evaluated neurophysiological and behavioral indices of distractibility across times prior to the night shift (T1), during night hours (T2), and after acute sleep deprivation (T3) in permanent hospital night workers with and without SWD. METHODS: Ten asymptomatic night workers (NW) and 18 NW with SWD participated in a 25-h sleep deprivation study. Circadian phase was evaluated by dim-light salivary melatonin onset (DLMO)...
March 2014: Sleep
Valentina Gumenyuk, Thomas Roth, Christopher L Drake
Most night workers are unable to adjust their circadian rhythms to the atypical hours of sleep and wake. Between 10% and 30% of shiftworkers report symptoms of excessive sleepiness and/or insomnia consistent with a diagnosis of shift work disorder (SWD). Difficulties in attaining appropriate shifts in circadian phase, in response to night work, may explain why some individuals develop SWD. In the present study, it was hypothesized that disturbances of sleep and wakefulness in shiftworkers are related to the degree of mismatch between their endogenous circadian rhythms and the night-work schedule of sleep during the day and wake activities at night...
August 2012: Chronobiology International
Mariana G Figueiro, Mark S Rea
BACKGROUND: A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band "green" light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep)...
2012: BMC Research Notes
Anne-Marie Chang, Nayantara Santhi, Melissa St Hilaire, Claude Gronfier, Dayna S Bradstreet, Jeanne F Duffy, Steven W Lockley, Richard E Kronauer, Charles A Czeisler
Light exposure in the early night induces phase delays of the circadian rhythm in melatonin in humans. Previous studies have investigated the effect of timing, intensity, wavelength, history and pattern of light stimuli on the human circadian timing system. We present results from a study of the duration–response relationship to phase-delaying bright light. Thirty-nine young healthy participants (16 female; 22.18±3.62 years) completed a 9-day inpatient study. Following three baseline days, participants underwent an initial circadian phase assessment procedure in dim light (<3 lux), and were then randomized for exposure to a bright light pulse (∼10,000 lux) of 0...
July 1, 2012: Journal of Physiology
Deirdre A Conroy, Ilana S Hairston, J Todd Arnedt, Robert F Hoffmann, Roseanne Armitage, Kirk J Brower
Sleep disturbances in alcohol-dependent (AD) individuals may persist despite abstinence from alcohol and can influence the course of the disorder. Although the mechanisms of sleep disturbances of AD are not well understood and some evidence suggests dysregulation of circadian rhythms, dim light melatonin onset (DLMO) has not previously been assessed in AD versus healthy control (HC) individuals in a sample that varied by sex and race. The authors assessed 52 AD participants (mean ± SD age: 36.0 ± 11...
February 2012: Chronobiology International
Barbara L Parry, Charles J Meliska, Diane L Sorenson, L Fernando Martínez, Ana M López, Jeffrey A Elliott, Richard L Hauger
The authors previously observed blunted phase-shift responses to morning bright light in women with premenstrual dysphoric disorder (PMDD). The aim of this study was to determine if these findings could be replicated using a higher-intensity, shorter-duration light pulse and to compare these results with the effects of an evening bright-light pulse. In 17 PMDD patients and 14 normal control (NC) subjects, the authors measured plasma melatonin at 30-min intervals from 18:00 to 10:00 h in dim (<30 lux) or dark conditions the night before (Night 1) and after (Night 3) a bright-light pulse (administered on Night 2) in both follicular and luteal menstrual cycle phases...
May 2011: Chronobiology International
Henry Keijzer, Marcel G Smits, Twan Peeters, Caspar W N Looman, Silvia C Endenburg, Jacqueline M T Klein Gunnewiek
BACKGROUND: Dim Light Melatonin Onset (DLMO) can be calculated within a 5-point partial melatonin curve in saliva collected at home. We retrospectively analyzed the patient melatonin measurements sample size of the year 2008 to evaluate these DLMO calculations and studied the correlation between diary or polysomnography (PSG) sleep onset and DLMO. METHODS: Patients completed an online questionnaire. If this questionnaire pointed to a possible Delayed Sleep Phase Disorder (DSPD), saliva collection devices were sent to the patient...
August 17, 2011: Clinica Chimica Acta; International Journal of Clinical Chemistry
Karuna Dewan, Susan Benloucif, Kathryn Reid, Lisa F Wolfe, Phyllis C Zee
STUDY OBJECTIVES: To evaluate the effect of increasing the intensity and/or duration of exposure on light-induced changes in the timing of the circadian clock of humans. DESIGN: Multifactorial randomized controlled trial, between and within subject design SETTING: General Clinical Research Center (GCRC) of an academic medical center PARTICIPANTS: 56 healthy young subjects (20-40 years of age) INTERVENTIONS: Research subjects were admitted for 2 independent stays of 4 nights/3 days for treatment with bright or dim-light (randomized order) at a time known to induce phase delays in circadian timing...
May 2011: Sleep
Helen J Burgess
Partial sleep deprivation is increasingly common in modern society. This study examined for the first time if partial sleep deprivation alters circadian phase shifts to bright light in humans. Thirteen young healthy subjects participated in a repeated-measures counterbalanced design with 2 conditions. Each condition had baseline sleep, a dim-light circadian phase assessment, a 3-day phase-advancing protocol with morning bright light, then another phase assessment. In one condition (no sleep deprivation), subjects had an 8-h sleep opportunity per night during the advancing protocol...
December 2010: Journal of Biological Rhythms
Michel A Paul, Gary W Gray, Harris R Lieberman, Ryan J Love, James C Miller, Matthew Trouborst, Josephine Arendt
INTRODUCTION: Melatonin and light treatment are recommended for hastening adaptation to time zone change. We evaluated an afternoon regimen of 3 mg sustained release (SR) melatonin with and without next morning green light treatment for circadian phase advance. Effects of melatonin and light were tested separately and then combined to determine if the total phase change is additive or synergistic. MATERIAL AND METHODS: For each condition (melatonin, placebo, light, melatonin plus light), 11 subjects spent from Tuesday evening until Friday afternoon in the laboratory...
March 2011: Psychopharmacology
Stephanie J Crowley, Mary A Carskadon
Adolescents often report shorter time in bed and earlier wake-up times on school days compared to weekend days. Extending sleep on weekend nights may reflect a "recovery" process as youngsters try to compensate for an accumulated school-week sleep debt. The authors examined whether the circadian timing system of adolescents shifted after keeping a common late weekend "recovery" sleep schedule; it was hypothesized that a circadian phase delay shift would follow this later and longer weekend sleep. The second aim of this study was to test whether modifying sleep timing or light exposure on weekends while still providing recovery sleep can stabilize the circadian system...
August 2010: Chronobiology International
W Braam, R Didden, A P H M Maas, H Korzilius, M G Smits, L M G Curfs
BACKGROUND: Persons with intellectual disability (ID) and sleep problems exhibit more daytime challenging behaviours than persons with ID without sleep problems. Several anecdotal reports suggest that melatonin is not only effective in the treatment of insomnia, but also decreases daytime challenging behaviour. However, the effect of melatonin treatment on daytime challenging behaviour in persons with ID has not been investigated in a randomised controlled trial. METHOD: We investigated the effects of melatonin on challenging behaviour using data from two randomised controlled trials on the efficacy of melatonin on sleep problems in 49 persons (25 men, 24 women; mean age 18...
January 1, 2010: Journal of Intellectual Disability Research: JIDR
Marie Dumont, Hélène Blais, Joanie Roy, Jean Paquet
Circadian misalignment between the endogenous circadian signal and the imposed rest-activity cycle is one of the main sources of sleep and health troubles in night shift workers. Timed bright light exposure during night work can reduce circadian misalignment in night workers, but this approach is limited by difficulties in incorporating bright light treatment into most workplaces. Controlled light and dark exposure during the daytime also has a significant impact on circadian phase and could be easier to implement in real-life situations...
October 2009: Journal of Biological Rhythms
Mark R Smith, Louis F Fogg, Charmane I Eastman
Scheduled bright light and darkness can phase shift the circadian clocks of night workers for complete adaptation to a night work, day sleep schedule, but few night workers would want this because it would leave them out of phase with the diurnal world on days off. This is the final study in a series designed to produce a compromise circadian phase position for permanent night shift work in which the sleepiest circadian time is delayed out of the night work period and into the first half of the day sleep episode...
April 2009: Journal of Biological Rhythms
Mark R Smith, Charmane I Eastman
STUDY OBJECTIVE: To produce a compromise circadian phase position for permanent night shift work in which the sleepiest circadian time is delayed out of the night work period and into the first half of the day sleep period. This is predicted to improve night shift alertness and performance while permitting adequate late night sleep on days off. DESIGN: Between-subjects. SETTING: Home and laboratory. PARTICIPANTS: 24 healthy subjects...
December 2008: Sleep
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