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Diurnal spectral sensitivity of the acute alerting effects of light

Rahman, S.A., Flynn-Evans, E.E., Aeschbach, D., Brainard, G.C., Czeisler, C.A. and Lockley, Steven (2014) Diurnal spectral sensitivity of the acute alerting effects of light Sleep, 37 (2). pp. 271-281.

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Study Objectives: Previous studies have demonstrated short-wavelength sensitivity for the acute alerting response to nocturnal light exposure. We assessed daytime spectral sensitivity in alertness, performance, and waking electroencephalogram (EEG). Design: Between-subjects (n = 8 per group). Setting: Inpatient intensive physiologic monitoring unit. Participants: Sixteen healthy young adults (mean age ± standard deviation = 23.8 ± 2.7 y). Interventions: Equal photon density exposure (2.8 � 1013 photons/cm2/s) to monochromatic 460 nm (blue) or 555 nm (green) light for 6.5 h centered in the middle of the 16-h episode of wakefulness during the biological day. Results were compared retrospectively to 16 individuals who were administered the same light exposure during the night. Measurements and Results: Daytime and nighttime 460-nm light exposure significantly improved auditory reaction time (P < 0.01 and P < 0.05, respectively) and reduced attentional lapses (P < 0.05), and improved EEG correlates of alertness compared to 555-nm exposure. Whereas subjective sleepiness ratings did not differ between the two spectral conditions during the daytime (P > 0.05), 460-nm light exposure at night significantly reduced subjective sleepiness compared to 555-nm light exposure at night (P < 0.05). Moreover, nighttime 460-nm exposure improved alertness to near-daytime levels. Conclusions: The alerting effects of short-wavelength 460-nm light are mediated by counteracting both the circadian drive for sleepiness and homeostatic sleep pressure at night, but only via reducing the effects of homeostatic sleep pressure during the day.

Item Type: Article
Authors :
Rahman, S.A.
Flynn-Evans, E.E.
Aeschbach, D.
Brainard, G.C.
Czeisler, C.A.
Date : 2014
DOI : 10.5665/sleep.3396
Uncontrolled Keywords : Alertness, Circaidian, Homeostatic, Light, Short-wavelength light, Sleep, acute alerting response, adult, alertness, article, attention disturbance, auditory response, circadian rhythm, cosmological phenomena, daytime, electroencephalogram, homeostatic sleep pressure, human, human experiment, light exposure, male, night, normal human, performance, priority journal, reaction time, sleep parameters, somnolence, spectral sensitivity, wakefulness, Alertness, circaidian, homeostatic, light, short-wavelength light, sleep, Adult, Attention, Circadian Rhythm, Darkness, Electroencephalography, Homeostasis, Humans, Light, Male, Sleep Stages, Time Factors, Wakefulness, Young Adult
Depositing User : Clive Harris
Date Deposited : 17 Jun 2020 01:19
Last Modified : 17 Jun 2020 01:19

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