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The effects of spectral tuning of evening ambient light on melatonin suppression, alertness and sleep

Rahman, S.A., St. Hilaire, M.A. and Lockley, S.W. (2017) The effects of spectral tuning of evening ambient light on melatonin suppression, alertness and sleep Physiology and Behavior, 177. pp. 221-229.

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We compared the effects of bedroom-intensity light from a standard fluorescent and a blue- (i.e., short-wavelength) depleted LED source on melatonin suppression, alertness, and sleep. Sixteen healthy participants (8 females) completed a 4-day inpatient study. Participants were exposed to blue-depleted circadian-sensitive (C-LED) light and a standard fluorescent light (FL, 4100 K) of equal illuminance (50 lx) for 8 h prior to a fixed bedtime on two separate days in a within-subject, randomized, cross-over design. Each light exposure day was preceded by a dim light (< 3 lx) control at the same time 24 h earlier. Compared to the FL condition, control-adjusted melatonin suppression was significantly reduced. Although subjective sleepiness was not different between the two light conditions, auditory reaction times were significantly slower under C-LED conditions compared to FL 30 min prior to bedtime. EEG-based correlates of alertness corroborated the reduced alertness under C-LED conditions as shown by significantly increased EEG spectral power in the delta-theta (0.5�8.0 Hz) bands under C-LED as compared to FL exposure. There was no significant difference in total sleep time (TST), sleep efficiency (SE%), and slow-wave activity (SWA) between the two conditions. Unlike melatonin suppression and alertness, a significant order effect was observed on all three sleep variables, however. Individuals who received C-LED first and then FL had increased TST, SE% and SWA averaged across both nights compared to individuals who received FL first and then C-LED. These data show that the spectral characteristics of light can be fine-tuned to attenuate non-visual responses to light in humans. © 2017 Elsevier Inc.

Item Type: Article
Authors :
Rahman, S.A.
St. Hilaire, M.A.
Date : 2017
DOI : 10.1016/j.physbeh.2017.05.002
Uncontrolled Keywords : Alertness, Circadian, Light, Melatonin, Sleep, Spectrum, melatonin, melatonin, alertness, Article, blue light, circadian rhythm, comparative study, controlled study, crossover procedure, electroencephalogram, enzyme repression, female, fluorescent lighting, human, human experiment, light emitting diode, light exposure, light intensity, male, night sleep, normal human, photobiology, priority journal, randomized controlled trial, reaction time, sleep quality, sleep time, slow wave sleep, somnolence, spectral sensitivity, time, brain, electroencephalography, illumination, light, metabolism, physiology, polysomnography, radiation response, sleep, time factor, wakefulness, young adult, Brain, Circadian Rhythm, Cross-Over Studies, Electroencephalography, Female, Humans, Light, Lighting, Male, Melatonin, Polysomnography, Sleep, Time Factors, Wakefulness, Young Adult
Depositing User : Clive Harris
Date Deposited : 17 Jun 2020 01:01
Last Modified : 17 Jun 2020 01:01

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