scholarly journals Short-Wavelength Light Enhances Cortisol Awakening Response in Sleep-Restricted Adolescents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mariana G. Figueiro ◽  
Mark S. Rea
Keyword(s):  
Adrenal Gland ◽  
Short Wavelength ◽  
Light Exposure ◽  
Secondary Analysis ◽  
Cortisol Awakening Response ◽  
Dim Light ◽  
Short Wavelength Light ◽  
The Impact ◽  
Rising Time ◽  
Wavelength Light

Levels of cortisol, a hormone produced by the adrenal gland, follow a daily, 24-hour rhythm with concentrations reaching a minimum in the evening and a peak near rising time. In addition, cortisol levels exhibit a sharp peak in concentration within the first hour after waking; this is known as the cortisol awakening response (CAR). The present study is a secondary analysis of a larger study investigating the impact of short-wavelength(λmax≈470 nm)light on CAR in adolescents who were sleep restricted. The study ran over the course of three overnight sessions, at least one week apart. The experimental sessions differed in terms of the light exposure scenarios experienced during the evening prior to sleeping in the laboratory and during the morning after waking from a 4.5-hour sleep opportunity. Eighteen adolescents aged 12–17 years were exposed to dim light or to 40 lux (0.401 W/m2) of 470-nm peaking light for 80 minutes after awakening. Saliva samples were collected every 20 minutes to assess CAR. Exposure to short-wavelength light in the morning significantly enhanced CAR compared to dim light. Morning exposure to short-wavelength light may be a simple, yet practical way to better prepare adolescents for an active day.

scholarly journals Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness

2021 ◽  
Vol 3 (1) ◽  
pp. 66-86
Author(s):  
Christopher Höhn ◽  
Sarah R. Schmid ◽  
Christina P. Plamberger ◽  
Kathrin Bothe ◽  
Monika Angerer ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Blue Light ◽  
Short Wavelength ◽  
Light Filter ◽  
Negative Effects ◽  
Sleep Physiology ◽  
Short Wavelength Light ◽  
Blue Light Filter ◽  
The Impact ◽  
Wavelength Light

Smartphone usage strongly increased in the last decade, especially before bedtime. There is growing evidence that short-wavelength light affects hormonal secretion, thermoregulation, sleep and alertness. Whether blue light filters can attenuate these negative effects is still not clear. Therefore, here, we present preliminary data of 14 male participants (21.93 ± 2.17 years), who spent three nights in the sleep laboratory, reading 90 min either on a smartphone (1) with or (2) without a blue light filter, or (3) on printed material before bedtime. Subjective sleepiness was decreased during reading on a smartphone, but no effects were present on evening objective alertness in a GO/NOGO task. Cortisol was elevated in the morning after reading on the smartphone without a filter, which resulted in a reduced cortisol awakening response. Evening melatonin and nightly vasodilation (i.e., distal-proximal skin temperature gradient) were increased after reading on printed material. Early slow wave sleep/activity and objective alertness in the morning were only reduced after reading without a filter. These results indicate that short-wavelength light affects not only circadian rhythm and evening sleepiness but causes further effects on sleep physiology and alertness in the morning. Using a blue light filter in the evening partially reduces these negative effects.

scholarly journals Relationship of Morning Cortisol to Circadian Phase and Rising Time in Young Adults with Delayed Sleep Times

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Mark S. Rea ◽  
Mariana G. Figueiro ◽  
Katherine M. Sharkey ◽  
Mary A. Carskadon
Keyword(s):  
Experimental Data ◽  
Secondary Analysis ◽  
Cortisol Awakening Response ◽  
Circadian Phase ◽  
Morning Cortisol ◽  
Dim Light ◽  
Delayed Sleep ◽  
Relationship Of ◽  
The Relationship ◽  
Rising Time

The present study was aimed at further elucidating the relationship between circadian phase, rising time, and the morning cortisol awakening response (CAR). The results presented here are a secondary analysis of experimental data obtained from a study of advanced sleep-wake schedules and light exposures on circadian phase advances measured by dim-light melatonin onset (DLMO). The present results demonstrate that morning CAR is strongly related to rising time and more weakly related to DLMO phase.

scholarly journals Effects of an advanced sleep schedule and morning short wavelength light exposure on circadian phase in young adults with late sleep schedules

2011 ◽  
Vol 12 (7) ◽  
pp. 685-692 ◽  
Author(s):  
Katherine M. Sharkey ◽  
Mary A. Carskadon ◽  
Mariana G. Figueiro ◽  
Yong Zhu ◽  
Mark S. Rea
Keyword(s):  
Young Adults ◽  
Short Wavelength ◽  
Light Exposure ◽  
Circadian Phase ◽  
Sleep Schedule ◽  
Short Wavelength Light ◽  
Wavelength Light

scholarly journals No evidence for an S cone contribution to the human circadian response to light

2019 ◽  
Author(s):  
Manuel Spitschan ◽  
Rafael Lazar ◽  
Ebru Yetik ◽  
Christian Cajochen
Keyword(s):  
Retinal Ganglion Cells ◽  
Short Wavelength ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Retinal Ganglion ◽  
Long Wavelength ◽  
Short Wavelength Light ◽  
The Brain ◽  
Wavelength Light

Exposure to even moderately bright, short-wavelength light in the evening can strongly suppress the production of melatonin and can delay our circadian rhythm. These effects are mediated by the retinohypothalamic pathway, connecting a subset of retinal ganglion cells to the circadian pacemaker in the suprachiasmatic nucleus (SCN) in the brain. These retinal ganglion cells directly express the photosensitive protein melanopsin, rendering them intrinsically photosensitive (ipRGCs). But ipRGCs also receive input from the classical photoreceptors — the cones and rods. Here, we examined whether the short-wavelength-sensitive (S) cones contribute to circadian photoreception by using lights which differed exclusively in the amount of S cone excitation by almost two orders of magnitude (ratio 1:83), but not in the excitation of long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cones, rods, and melanopsin. We find no evidence for a role of S cones in the acute alerting and melatonin supressing response to evening light exposure, pointing to an exclusive role of melanopsin in driving circadian responses.

scholarly journals Interventions to reduce short-wavelength (“blue”) light exposure at night and their effects on sleep: A systematic review and meta-analysis

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Ari Shechter ◽  
Kristal A Quispe ◽  
Jennifer S Mizhquiri Barbecho ◽  
Cody Slater ◽  
Louise Falzon
Keyword(s):  
Systematic Review ◽  
Effect Size ◽  
Short Wavelength ◽  
Total Sleep Time ◽  
Light Exposure ◽  
Meta Analysis ◽  
Sleep Time ◽  
Combined Effect ◽  
Short Wavelength Light ◽  
Wavelength Light

Abstract The sleep-wake and circadian cycles are influenced by light, particularly in the short-wavelength portion of the visible spectrum. Most personal light-emitting electronic devices are enriched in this so-called “blue” light. Exposure to these devices in the evening can disturb sleep. Interventions to reduce short-wavelength light exposure before bedtime may reduce adverse effects on sleep. We conducted a systematic review and meta-analysis to examine the effect of wearing color-tinted lenses (e.g. orange or amber) in frames to filter short-wavelength light exposure to the eye before nocturnal sleep. Outcomes were self-reported or objective measures of nocturnal sleep. Relatively few (k = 12) studies have been done. Study findings were inconsistent, with some showing benefit and others showing no effect of intervention. Meta-analyses yielded a small-to-medium magnitude combined effect size for sleep efficiency (Hedge’s g = 0.31; 95% CI: −0.05, 0.66; I2 = 38.16%; k = 7), and a small-to-medium combined effect size for total sleep time (Hedge’s g = 0.32; 95% CI: 0.01, 0.63; I2 = 12.07%; k = 6). For self-report measures, meta-analysis yielded a large magnitude combined effects size for Pittsburgh Sleep Quality Index ratings (Hedge’s g = −1.25; 95% CI: −2.39, −0.11; I2 = 36.35%; k = 3) and a medium combined effect size for total sleep time (Hedge’s g = 0.51; 95% CI: 0.18, 0.84; I2 = 0%; k = 3), Overall, there is some, albeit mixed, evidence that this approach can improve sleep, particularly in individuals with insomnia, bipolar disorder, delayed sleep phase syndrome, or attention-deficit hyperactive disorder. Considering the ubiquitousness of short-wavelength-enriched light sources, future controlled studies to examine the efficacy of this approach to improve sleep are warranted. Systematic review registration: PROSPERO 2018 CRD42018105854.

scholarly journals 0172 Blue-Light Blockers and Sleep: A Meta-Analysis of Intervention Studies

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A68-A69
Author(s):  
A Shechter ◽  
K A Quispe ◽  
J S Mizhquiri Barbecho ◽  
L Falzon
Keyword(s):  
Short Wavelength ◽  
Light Exposure ◽  
Meta Analysis ◽  
Electronic Devices ◽  
Sleep Onset ◽  
Sleep Time ◽  
Combined Effect ◽  
Light Emitting ◽  
Short Wavelength Light ◽  
Wavelength Light

Abstract Introduction Sleep and circadian physiology are influenced by external light, particularly within the short-wavelength portion of the visible spectrum (~450–480 nm). Most personal light-emitting electronic devices (e.g., tablets, smartphones, computers) are enriched in this so-called “blue” light. Interventions to reduce short-wavelength light exposure to the eyes before bedtime may help mitigate adverse effects of light-emitting electronic devices on sleep. Methods We conducted a meta-analysis of intervention studies on the effects of wearing color-tinted lenses (e.g., orange or amber) in frames in the evening before sleep to selectively filter short-wavelength light exposure to the eyes. Outcomes were self-reported or objective (wrist-accelerometer) measures of nocturnal sleep. Databases (MEDLINE, EMBASE, Cochrane Library, PsycINFO, CINAHL, AMED) were searched from inception to November 2019. PROSPERO Registration: CRD42018105854. Results Ten studies were identified (7 randomized controlled trials; 3 before-after studies). Findings of individual studies were inconsistent, with some showing benefit and others showing no effect of intervention. For objective sleep onset latency, there was a significant modest-sized combined effect (Hedge’s g=-0.52, 95% CI: -1.27-0.24, Z=-2.94, p=0.003, I2=16.6%, k=3). There was a minor but non-statistically significant combined effect for objective sleep efficiency (Hedge’s g=0.24, 95% CI: -0.16–0.64, Z=1.69, p=0.09, I2=23.7%, k=5). There were no significant combined effects for objective measures of total sleep time and wake after sleep onset. For self-reported total sleep time, there was a statistically significant medium-sized combined effect (Hedge’s g=0.61, 95% CI: 0.14–1.09, Z=5.56, p<0.01, I2=0%, k=3). Conclusion There is mixed evidence that this approach can improve sleep. Relatively few studies have been conducted, and most did not assess light levels or melatonin. The “blue-blocker” intervention may be particularly useful in individuals with insomnia, delayed sleep phase syndrome, or attention-deficit hyperactive disorder. Considering the ubiquitousness of short wavelength-enriched light sources and the potential for widespread sleep disturbance, future controlled studies examining the efficacy of this approach to improve sleep are warranted. Support N/A

257 How Much Blue Do Blue-Blockers Block if Blue-Blockers Do Block Blue?

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A103-A103
Author(s):  
Brooke Mason ◽  
Andrew Tubbs ◽  
William Killgore ◽  
Fabian-Xosé Fernandez ◽  
Michael Grandner
Keyword(s):  
Light Source ◽  
Blue Light ◽  
Short Wavelength ◽  
Light Exposure ◽  
Visible Spectrum ◽  
Group Differences ◽  
Melatonin Secretion ◽  
Short Wavelength Light ◽  
Wavelength Light ◽  
One Way Anova

Abstract Introduction Short-wavelength light (440-530nm) can suppress endogenous melatonin secretion from the pineal gland. This has been observed in realworld settings when people use electronic media at night that emits light from this part of the visible spectrum. Blue-blocking glasses are a possible intervention to reduce blue light exposure. The present study evaluated the ability of commercially available blue-blockers to block blue light emitted by LEDs. Methods A calibrated spectroradiometer (Ocean Insight), cosine corrector, optic fiber, and software package were used to measure the absolute irradiance (uW/cm^2/nm) generated from a blue light source (Phillips Go Lite Blu) in an otherwise completely dark room. Thirty-one different commercially-available blue-blockers were individually placed between the cosine corrector and the light source at a standardized distance, and then intensity was measured and analyzed. Lenses were evaluated with regards to the amount of blue light they suppressed both individually and grouped by lens tint: red-tinted lenses (RTL), orange-tinted lenses (OTL), orange-tinted lenses with blue reflectivity (OBL), brown-tinted lenses (BTL), yellow-tinted lenses (YTL), and clear lenses with blue reflectivity (RBL). Results RTL blocked 100% of the short-wavelength light, while OTL and OBL blocked 99%, BTL blocked 66%, YTL blocked 38%, and RBL blocked 11% of it. This represented a statistically significant between-group difference (one-way ANOVA, < 0.0001). Within groups, there was variability in performance among individual lenses, though this variability was small compared to the between-group differences. Conclusion The RTL, OTL, and OBL block light best capable of suppressing melatonin secretion at night (440-530 nm); with slightly less efficacy, BTL and YTL also restricted much of the light exposure. Lastly, RBL were not effective at curtailing short-wavelength light. Those looking to optimize blue-blocking capabilities should use RTL, OTL, and OBL, rather than other lens types. Support (if any):

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