Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression
Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA. Applied ergonomics
(Impact Factor: 2.02).
07/2012; 44(2). DOI: 10.1016/j.apergo.2012.07.008
Exposure to light from self-luminous displays may be linked to increased risk for sleep disorders because these devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Thirteen participants experienced three experimental conditions in a within-subjects design to investigate the impact of self-luminous tablet displays on nocturnal melatonin suppression: 1) tablets-only set to the highest brightness, 2) tablets viewed through clear-lens goggles equipped with blue light-emitting diodes that provided 40 lux of 470-nm light at the cornea, and 3) tablets viewed through orange-tinted glasses (dark control; optical radiation <525 nm ≈ 0). Melatonin suppressions after 1-h and 2-h exposures to tablets viewed with the blue light were significantly greater than zero. Suppression levels after 1-h exposure to the tablets-only were not statistically different than zero; however, this difference reached significance after 2 h. Based on these results, display manufacturers can determine how their products will affect melatonin levels and use model predictions to tune the spectral power distribution of self-luminous devices to increase or to decrease stimulation to the circadian system.
Available from: Lisa A. Wines
- "Many adolescents now use IPADs for reading and game play. Researchers have shown that the blue light from self-luminous tablets can have a negative effect on natural melatonin production and thus disrupt sleep (Wood, Rea, Plitnick, & Figueiro, 2013). "
A Counselor's Guide to Diagnosis and Treating Children and Adolescent DSM-5 Disorders, Edited by Brande Flamez, Carl J. Sheperis, 01/2015: chapter Sleep-Wake and Somatic Disorders; Wiley.
Available from: Vincent van der Vinne
- "In addition, tailored interventions to reduce especially short wavelength (blue) light in the evenings and/or to increase light exposure in the mornings could help to synchronize the students' circadian clocks to their school schedules. The circadian clock is most sensitive to short wavelengths (Brainard et al., 2001), and studies have shown that especially blue light from computers and televisions interferes with sleep and the circadian rhythm (Wood et al., 2013; van der Lely et al., 2014). However, such behavioral interventions are as difficult to achieve on a population level, as are changes in school start times. "
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ABSTRACT: Circadian clocks of adolescents typically run late – including sleep times – while adolescents generally are expected at school early in the morning. Due to this mismatch between internal (circadian) and external (social) times, they suffer from chronic sleep deficiency, which, in turn, affects academic performance negatively. This constellation impacts students’ future career prospects. Our study correlates chronotype and exam performance. In total, 4,734 grades were collected from 741 Dutch high school students (ages 11-18 yrs) who had completed the Munich ChronoType Questionnaire (MCTQ) to estimate their internal time. Overall, the lowest grades were obtained by students who were very late chronotypes (MSFsc > 5.31 h) or slept very short on schooldays (SDw < 7.03 h). The effect of chronotype on exam performance depended on the time of day that exams were taken. Opposed to late types, early chronotypes obtained significantly higher grades during the early (8:15-9:45) and late (10:00-12:15) morning. This group difference in grades disappeared in the early afternoon (12:45-15:00). Late types also obtained lower grades than early types when tested at the same internal time (hours after MSFsc), which may reflect general attention and learning disadvantages of late chronotypes during the early morning. Our results support delaying high school starting times as well as scheduling exams in the early afternoon to avoid discrimination of late chronotypes, and to give all high school students equal academic opportunities.
Journal of Biological Rhythms 12/2014; 30(1). DOI:10.1177/0748730414564786 · 2.77 Impact Factor
Available from: Shelley Hershner
- "Melatonin is suppressed by light, and light sources as low 200–300 lux (room lights) can cause suppression.53 The amount of light from technologic devices is variable; for example, a tablet computer generated 50 lux suppressed melatonin in a cohort of college students after 2 hours of use.54 A case report describes a student in Brazil who had a 40-minute delay in sleep on the weekends when electric lights were installed.55 "
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ABSTRACT: Daytime sleepiness, sleep deprivation, and irregular sleep schedules are highly prevalent among college students, as 50% report daytime sleepiness and 70% attain insufficient sleep. The consequences of sleep deprivation and daytime sleepiness are especially problematic to college students and can result in lower grade point averages, increased risk of academic failure, compromised learning, impaired mood, and increased risk of motor vehicle accidents. This article reviews the current prevalence of sleepiness and sleep deprivation among college students, contributing factors for sleep deprivation, and the role of sleep in learning and memory. The impact of sleep and sleep disorders on academics, grade point average, driving, and mood will be examined. Most importantly, effective and viable interventions to decrease sleepiness and sleep deprivation through sleep education classes, online programs, encouragement of naps, and adjustment of class time will be reviewed. This paper highlights that addressing sleep issues, which are not often considered as a risk factor for depression and academic failure, should be encouraged. Promotion of university and college policies and class schedules that encourage healthy and adequate sleep could have a significant impact on the sleep, learning, and health of college students. Future research to investigate effective and feasible interventions, which disseminate both sleep knowledge and encouragement of healthy sleep habits to college students in a time and cost effective manner, is a priority.
Nature and Science of Sleep 06/2014; 6:73-84. DOI:10.2147/NSS.S62907
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