Abstract
In 2020, the World Health Organization formally recognized addiction to digital technology (connected devices) as a worldwide problem, where excessive online activity and internet use lead to inability to manage time, energy, and attention during daytime and produce disturbed sleep patterns or insomnia during nighttime. Recent studies have shown that the problem has increased in magnitude worldwide during the COVID-19 pandemic. The extent to which dysfunctional sleep is a consequence of altered motivation, memory function, mood, diet, and other lifestyle variables or results from excess of blue-light exposure when looking at digital device screens for long hours at day and night is one of many still unresolved questions. This article offers a narrative overview of some of the most recent literature on this topic. The analysis provided offers a conceptual basis for understanding digital addiction as one of the major reasons why people, and adolescents in particular, sleep less and less well in the digital age. It discusses definitions as well as mechanistic model accounts in context. Digital addiction is identified as functionally equivalent to all addictions, characterized by the compulsive, habitual, and uncontrolled use of digital devices and an excessively repeated engagement in a particular online behavior. Once the urge to be online has become uncontrollable, it is always accompanied by severe sleep loss, emotional distress, depression, and memory dysfunction. In extreme cases, it may lead to suicide. The syndrome has been linked to the known chronic effects of all drugs, producing disturbances in cellular and molecular mechanisms of the GABAergic and glutamatergic neurotransmitter systems. Dopamine and serotonin synaptic plasticity, essential for impulse control, memory, and sleep function, are measurably altered. The full spectrum of behavioral symptoms in digital addicts include eating disorders and withdrawal from outdoor and social life. Evidence pointing towards dysfunctional melatonin and vitamin D metabolism in digital addicts should be taken into account for carving out perspectives for treatment. The conclusions offer a holistic account for digital addiction, where sleep deficit is one of the key factors.
https://pubmed.ncbi.nlm.nih.gov/35682491/
Sleep problems
Lack of sleep is often a consequence of modern man's hectic life, and it can have many unfortunate physical as well as psychological side effects. For example, the hormonal balance, the immune system and the metabolism are affected, as are the ability to concentrate, memory, performance, learning ability, and mood, and the body ages faster.
Description
The cause of sleep problems is, among other things, imbalances in our natural circadian rhythm, as the natural production of melatonin is inhibited due to blue light, which comes from light pollution (artificial lighting, TV and PCs).
Over a day, the body can maintain a maximum production of the natural sleep aid, melatonin, for approximately 10-12 hours straight at most. In adults with a well-balanced circadian rhythm, the production of melatonin takes place, typically for 9-10 hours during the dark night hours.
Many people try to solve sleep problems with expensive and addictive sleeping pills, but there is a healthy alternative, namely sleep glasses. This is a simple solution which, moreover, works after just 1-5 days of use. In addition, sleep glasses are completely free of annoying side effects.
The effect of sleep glasses
In people with a well-balanced circadian rhythm, the production of the body's natural sleep aid, melatonin, takes place for 9-10 hours in a row, out of the 24 hours of the day.
People who for one reason or another have imbalances in their melatonin production can improve their sleep remarkably by using sleep glasses.
The result is that you fall asleep more easily. Sleep becomes sound and deep, and you wake up refreshed and rested in the morning, as melatonin production is decreasing.
Sleep glasses are a healthy alternative that generally work after just 1-5 days of use.
Tired children and young people
Far too many children and young people go to bed too late and get too little sleep. They are not rested when they are woken early in the morning because they have to go to kindergarten or school.
A rule of thumb is that children aged 5-9 should sleep 10-12 hours a night, children aged 10-13 should sleep 9-11 hours a night and teenagers should sleep 8-10 hours a night.
Many kindergarten and school children are barely awake during the first hours of kindergarten and school due to getting too few hours of sleep at night. This greatly affects their well-being and ability to learn.
The problem can be avoided by bringing forward the time in the evening when the production of melatonin starts. This is achieved by the child avoiding exposing his eyes to blue light for a few hours before the planned bedtime.
The big culprits today are smartphones, tablets, computers and TV, which many children and young people use right up until they go to sleep. They all emit blue light and this can cause children and young people to be unable to fall asleep.
The most practical method is to wear sleep glasses, which block the blue light in the light spectrum. As an alternative, you can use LED bulbs, which do not emit blue light, and corresponding screen filters, which are applied directly to TV and PC screens.
In the course of a few days, when the child has avoided blue light in the evening, the cycle for the production of melatonin will be advanced, so that it ends well before kindergarten or school.
In the winter, the progress can be consolidated by having the child receive light therapy with blue light shortly after waking up in the morning. Light therapy can be in the form of a light therapy lamp or a dawn simulator.
Research regarding sleep problems
Digital Addiction and Sleep
Int J Environ Res Public Health. 2022 Jun 5;19(11):6910. doi: 10.3390/ijerph19116910.Birgitta Dresp-Langley, Axel HuttPMID: 35682491 / PMCID: PMC9179985 / DOI: 10.3390/ijerph19116910
In 2020, the World Health Organisation formally recognised addiction to digital technology (connected devices) as a worldwide problem, where excessive online activity and internet use lead to an inability to...
Digital Addiction and Sleep
In 2020, the World Health Organisation formally recognised addiction to digital technology (connected devices) as a worldwide problem, where excessive online activity and internet use lead to an inability to manage time, energy and attention during the day and produce disturbed sleep patterns or insomnia during the night. To what extent dysfunctional sleep is a consequence of altered motivation, memory function, mood, diet and other lifestyle variables or results from excessive exposure to blue light when looking at digital device screens for long hours during the day and night is one of many still unclear questions. Once the urge to be online has become uncontrollable, it is always accompanied by severe sleep loss, emotional distress, depression and memory dysfunction. Behavioural symptoms in digital addicts include eating disorders and withdrawal from outdoor and social life. Evidence pointing toward dysfunctional melatonin and vitamin D metabolism in digital addicts should be taken into consideration to carve out perspectives for treatment. The findings offer a holistic account of digital addiction, where sleep deficit is one of the key factors.
Digital Addiction and Sleep
Int J Environ Res Public Health. 2022 Jun 5;19(11):6910. doi: 10.3390/ijerph19116910.
PMID: 35682491 / PMCID: PMC9179985 / DOI: 10.3390/ijerph19116910
Light pollution
Rev Prat. 2022 Feb;72(2):141-146.Jean-Louis Dufier, Yvan TouitouPMID: 35289519
Artificial light can be harmful to the retina compared to the toxicity of the blue light (380-500 nm) of the visible spectrum (380-700 nm) specifically used in light-emitting diodes (LEDs)....
Light pollution
Artificial light can be harmful to the retina compared to the toxicity of the blue light (380-500 nm) of the visible spectrum (380-700 nm) specifically used in light-emitting diodes (LEDs). Phototoxicity results from photochemical damage to the pigmented epithelium and retinal photoreceptors, which are responsible for the visual function of the retina. Their light-sensitive pigments, opsins for the cones and rhodopsin for the rods, are consumed during the day and regenerated at night. Exposure to light at night severely disrupts their metabolism. Exposure to artificial light at night has a detrimental effect on the internal clock. Light inhibits the secretion of melatonin and is able to speed up or slow down the internal clock depending on the time of exposure, causing desynchronisation. Shift and night workers, like teenagers, are exposed to light at night. The incidence of breast cancer is higher in nurses exposed to light at night and it is related to melatonin inhibition, sleep deprivation and desynchronisation. Teens' exposure to screens is also questionable because the LEDs on the devices emit a blue light whose impact on the internal clock is significant. The chronic desynchronisations of both shift workers and youths should be considered a major public health problem.
Light pollution
Rev Prat. 2022 Feb;72(2):141-146.
PMID: 35289519
Abstract
LIGHT POLLUTION Artificial light can be a polluting agent deleterious for the retina, in relation to the toxicity of the blue band (380-500 nm) of the visible spectrum (380-700nm) specifically used in light-emitting diodes (LEDs). Photo-toxicity results from photochemical damage to the pigmented epithelium and retinal photoreceptors responsible for the visual function of the retina. Their photosensitive pigments, opsins for the cones and rhodopsin for the sticks, are consumed during the day and regenerated at night. Exposure to light at night seriously disrupts their metabolism. Photo-toxicity, along with heredity, is a major factor in degenerative diseases of the retina with, in addition to, the impact of age and tobacco for the most common of them, age-related macular degeneration: ARMD. Exposure to artificial light at night (LAN) has a deleterious effect on the internal clock. Intrinsically photosensitive ganglion cells (ipRGSs) are responsible for the non-visual functions of the retina, and perceive the light signal that is transmitted to the internal clock to reach the pineal gland. Light inhibits the secretion of melatonin and is able to advance or delay the clock depending on the time of exposure, causing desynchronization. Shift and night workers, like teenagers, are exposed to LAN. The incidence of breast cancer, higher in nurses exposed to LAN, is related to melatonin inhibition, sleep deprivation and desynchronization. The exposure of adolescents to screens is also questionable because the LEDs of the devices emit a blue light, the impact of which on the clock is considerable. The chronic desynchronizations of both shiftworkers and adolescents should be considered a major public health concern.
https://pubmed.ncbi.nlm.nih.gov/35289519/
LIGHT POLLUTION Artificial light can be a polluting agent deleterious for the retina, in relation to the toxicity of the blue band (380-500 nm) of the visible spectrum (380-700nm) specifically used in light-emitting diodes (LEDs). Photo-toxicity results from photochemical damage to the pigmented epithelium and retinal photoreceptors responsible for the visual function of the retina. Their photosensitive pigments, opsins for the cones and rhodopsin for the sticks, are consumed during the day and regenerated at night. Exposure to light at night seriously disrupts their metabolism. Photo-toxicity, along with heredity, is a major factor in degenerative diseases of the retina with, in addition to, the impact of age and tobacco for the most common of them, age-related macular degeneration: ARMD. Exposure to artificial light at night (LAN) has a deleterious effect on the internal clock. Intrinsically photosensitive ganglion cells (ipRGSs) are responsible for the non-visual functions of the retina, and perceive the light signal that is transmitted to the internal clock to reach the pineal gland. Light inhibits the secretion of melatonin and is able to advance or delay the clock depending on the time of exposure, causing desynchronization. Shift and night workers, like teenagers, are exposed to LAN. The incidence of breast cancer, higher in nurses exposed to LAN, is related to melatonin inhibition, sleep deprivation and desynchronization. The exposure of adolescents to screens is also questionable because the LEDs of the devices emit a blue light, the impact of which on the clock is considerable. The chronic desynchronizations of both shiftworkers and adolescents should be considered a major public health concern.
https://pubmed.ncbi.nlm.nih.gov/35289519/
Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review
Chronobiol Int. 2021 Oct;38(10):1375-1383. doi: 10.1080/07420528.2021.1930029. Epub 2021 May 24.Landon Hester, Deanna Dang, Christopher J Barker, Michael Heath, Sidra Mesiya, Tekenari Tienabeso, Kevin WatsonPMID: 34030534 / DOI: 10.1080/07420528.2021.1930029
Sleep glasses have been studied in relation to insomnia, circadian rhythm disorder, shift work, jet lag and non-pathological sleep improvements. They have also been studied as a treatment for bipolar...
Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review
Sleep glasses have been studied in relation to insomnia, circadian rhythm disorder, shift work, jet lag and non-pathological sleep improvements. They have also been studied as a treatment for bipolar disorder, depression and postpartum depression. From 24 published trials focusing on sleep, there is considerable evidence that using sleep glasses is a successful treatment for sleep problems, jet lag and shift work.
Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review
Chronobiol Int. 2021 Oct;38(10):1375-1383. doi: 10.1080/07420528.2021.1930029. Epub 2021 May 24.
PMID: 34030534 / DOI: 10.1080/07420528.2021.1930029
Abstract
Blue-blocking glasses, also known as amber glasses, are plastic glasses that primarily block blue light. Blue-blocking glasses have been studied as a sleep intervention for insomnia, delayed sleep-phase disorder, shift work, jet lag, and nonpathologic sleep improvement. Blue-blocking glasses have also been studied as a treatment for bipolar disorder, major depression, and postpartum depression. Blue-blocking glasses improve sleep by inducing dim-light melatonin onset by reducing activation of intrinsically photosensitive retinal ganglion cells (ipRGCs) which are most sensitive to blue light and are a major input for circadian regulation; their mechanism for mood regulation is unclear but may be similar to that of dark therapy for bipolar disorder where patients are kept in darkness for an extended period every night. A systematic search of the scientific literature identified a total of 29 experimental publications involving evening wear of blue-blocking glasses for sleep or mood disorders. These consisted of 16 randomized controlled trials (RCTs) published in journals with a total of 453 patients, 5 uncontrolled trials, 1 case series, 1 case study, and 6 abstracts from conference proceedings. Only 1 case study and 1 RCT were for acutely manic patients but both found substantial decreases in manic symptoms with the use of blue-blocking glasses; these give preliminary clinical evidence of efficacy that makes blue-blocking glasses a high-yield intervention to study for bipolar disorder. Findings in the 3 publications for major depression and postpartum depression were heterogeneous and conflicting as to their efficacy. Out of the 24 publications focusing on sleep, there was substantial evidence for blue-blocking glasses being a successful intervention for reducing sleep onset latency in patients with sleep disorders, jet lag, or variable shift work schedules. Given the well-established biological mechanism and clinical research showing that blue-blocking glasses are effective for inducing sleep, they are a viable intervention to recommend to patients with insomnia or a delayed sleep phase.
https://pubmed.ncbi.nlm.nih.gov/34030534/
Blue-blocking glasses, also known as amber glasses, are plastic glasses that primarily block blue light. Blue-blocking glasses have been studied as a sleep intervention for insomnia, delayed sleep-phase disorder, shift work, jet lag, and nonpathologic sleep improvement. Blue-blocking glasses have also been studied as a treatment for bipolar disorder, major depression, and postpartum depression. Blue-blocking glasses improve sleep by inducing dim-light melatonin onset by reducing activation of intrinsically photosensitive retinal ganglion cells (ipRGCs) which are most sensitive to blue light and are a major input for circadian regulation; their mechanism for mood regulation is unclear but may be similar to that of dark therapy for bipolar disorder where patients are kept in darkness for an extended period every night. A systematic search of the scientific literature identified a total of 29 experimental publications involving evening wear of blue-blocking glasses for sleep or mood disorders. These consisted of 16 randomized controlled trials (RCTs) published in journals with a total of 453 patients, 5 uncontrolled trials, 1 case series, 1 case study, and 6 abstracts from conference proceedings. Only 1 case study and 1 RCT were for acutely manic patients but both found substantial decreases in manic symptoms with the use of blue-blocking glasses; these give preliminary clinical evidence of efficacy that makes blue-blocking glasses a high-yield intervention to study for bipolar disorder. Findings in the 3 publications for major depression and postpartum depression were heterogeneous and conflicting as to their efficacy. Out of the 24 publications focusing on sleep, there was substantial evidence for blue-blocking glasses being a successful intervention for reducing sleep onset latency in patients with sleep disorders, jet lag, or variable shift work schedules. Given the well-established biological mechanism and clinical research showing that blue-blocking glasses are effective for inducing sleep, they are a viable intervention to recommend to patients with insomnia or a delayed sleep phase.
https://pubmed.ncbi.nlm.nih.gov/34030534/
Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial
Sleep Health. 2021 Aug;7(4):485-490. doi: 10.1016/j.sleh.2021.02.004. Epub 2021 Mar 8.Jeremy A Bigalke, Ian M Greenlund, Jennifer R Nicevski, Jason R CarterPMID: 33707105 / DOI: 10.1016/j.sleh.2021.02.004
This study tests the hypothesis that sleep glasses improve subjective and objective sleep in a group of healthy adults. The study found that sleep glasses did not improve sleep duration...
Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial
This study tests the hypothesis that sleep glasses improve subjective and objective sleep in a group of healthy adults. The study found that sleep glasses did not improve sleep duration or sleep quality.
Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial
Sleep Health. 2021 Aug;7(4):485-490. doi: 10.1016/j.sleh.2021.02.004. Epub 2021 Mar 8.
PMID: 33707105 / DOI: 10.1016/j.sleh.2021.02.004
Abstract
Objectives: Evening blue light has been shown to suppress melatonin, which can negatively impact sleep quality. The impact of evening blue light blocking (BLB) interventions on sleep remains ambiguous due to lack of randomized control trials. The present study tests the hypothesis that BLB glasses improve subjective and objective sleep in a population of healthy adults.
Design: Two-week, randomized, controlled, crossover design.
Setting: At-home testing of individuals in Michigan and Montana.
Participants: Twenty healthy adults (11 men, 9 women, age: 32 ± 12, body mass index: 28 ± 4 kg/m2).
Intervention: Following a 1-week run-in baseline (ie, no glasses), participants were randomized to 1-week of BLB or control (ie, clear lens) glasses. Upon finishing the 1-week intervention, participants crossed over to the opposite condition. In both conditions, glasses were worn for 7 consecutive days from 6 PM until bedtime.
Measurements: Objective sleep parameters were obtained using wrist actigraphy. Subjective sleep measures were assessed using sleep diaries. Karolinska Sleep Diaries were used to assess perceived sleep quality.
Results: BLB reduced subjective sleep onset (21 ± 28 vs 24 ± 21 minute, P = .033) and awakenings (1.6 ± 1.0 vs 2.2 ± 1.0 awakenings, P = .019) compared to the control condition. In contrast, objective measures of sleep were not significantly impacted. In fact, our primary outcome variable of total sleep time (TST) tended to be paradoxically shorter in the BLB condition for both subjective (468 ± 45 vs 480 ± 48 minute, P = .066) and objective (433 ± 40 vs 449 ± 39 minute, P = .075) TST.
Conclusions: Blue light blocking glasses did not improve objective measures of sleep time or quality in healthy adults.
https://pubmed.ncbi.nlm.nih.gov/33707105/
Objectives: Evening blue light has been shown to suppress melatonin, which can negatively impact sleep quality. The impact of evening blue light blocking (BLB) interventions on sleep remains ambiguous due to lack of randomized control trials. The present study tests the hypothesis that BLB glasses improve subjective and objective sleep in a population of healthy adults.
Design: Two-week, randomized, controlled, crossover design.
Setting: At-home testing of individuals in Michigan and Montana.
Participants: Twenty healthy adults (11 men, 9 women, age: 32 ± 12, body mass index: 28 ± 4 kg/m2).
Intervention: Following a 1-week run-in baseline (ie, no glasses), participants were randomized to 1-week of BLB or control (ie, clear lens) glasses. Upon finishing the 1-week intervention, participants crossed over to the opposite condition. In both conditions, glasses were worn for 7 consecutive days from 6 PM until bedtime.
Measurements: Objective sleep parameters were obtained using wrist actigraphy. Subjective sleep measures were assessed using sleep diaries. Karolinska Sleep Diaries were used to assess perceived sleep quality.
Results: BLB reduced subjective sleep onset (21 ± 28 vs 24 ± 21 minute, P = .033) and awakenings (1.6 ± 1.0 vs 2.2 ± 1.0 awakenings, P = .019) compared to the control condition. In contrast, objective measures of sleep were not significantly impacted. In fact, our primary outcome variable of total sleep time (TST) tended to be paradoxically shorter in the BLB condition for both subjective (468 ± 45 vs 480 ± 48 minute, P = .066) and objective (433 ± 40 vs 449 ± 39 minute, P = .075) TST.
Conclusions: Blue light blocking glasses did not improve objective measures of sleep time or quality in healthy adults.
https://pubmed.ncbi.nlm.nih.gov/33707105/
Evaluation of Two Strategies for Alleviating the Impact on the Circadian Cycle of Smartphone Screens
Optom Vis Sci. 2020 Mar;97(3):207-217. doi: 10.1097/OPX.0000000000001485.Emiliano Teran, Cristo-Manuel Yee-Rendon, Jesus Ortega-Salazar, Pablo De Gracia, Efrain Garcia-Romo, Russell L WoodsPMID: 32168244 / DOI: 10.1097/OPX.0000000000001485
The purpose of this study was to compare the radiation from smartphones that hits the eyes when using an app with a night function, or computer glasses. Apps with night...
Evaluation of Two Strategies for Alleviating the Impact on the Circadian Cycle of Smartphone Screens
The purpose of this study was to compare the radiation from smartphones that hits the eyes when using an app with a night function, or computer glasses. Apps with night mode functionality in smartphones reduced MSVs by up to 93%. The "warmest" condition produced the least suppression of melatonin production. Computer glasses reduced the attenuation of melatonin by 33%, with computer glasses being more effective than tinted glasses. Smartphones can impair the regulation of the circadian rhythm at night. The activation of the app with a night mode function was more effective than computer glasses in reducing the amount of blue light (up to 2.25 times). These results can be transferred to most electronic devices because they share the same type of white light source as smartphones.
Evaluation of Two Strategies for Alleviating the Impact on the Circadian Cycle of Smartphone Screens
Optom Vis Sci. 2020 Mar;97(3):207-217. doi: 10.1097/OPX.0000000000001485.
PMID: 32168244 / DOI: 10.1097/OPX.0000000000001485
Abstract
Significance: Electronic display devices used before bed may negatively affect sleep quality through the effects of short-wavelength (blue) light on melatonin production and the circadian cycle. We quantified the efficacy of night-mode functions and blue-light-reducing lenses in ameliorating this problem.
Purpose: The purpose of this study was to compare the radiation produced by smartphones that reaches the eye when using night-mode functions or blue-light-reducing spectacle lenses.
Methods: Radiant flux of 64 smartphones was measured with an integrating sphere. The retinal illuminance was calculated from the radiant flux of the smartphones. For the night-mode functions, the spectra produced by the smartphones were measured. The transmittance of four blue-light-reducing spectacle lenses, which filter light with either antireflective coatings or tints, was measured using a spectrometer. To determine the impact of blue-light-reducing spectacles, the radiant flux of the smartphone was weighted by the transmission spectrum of these glasses. Visual and nonvisual (circadian) parameters were calculated to compute the melatonin suppression values (MSVs) through a logistic fitting of previously published data. The MSV was used as the figure of merit to evaluate the performance of blue-light spectacles and smartphone night-mode functions.
Results: Night-mode functions in smartphones reduced MSVs by up to 93%. The warmest mode produced the least suppression. Blue-light-reducing spectacles reduced melatonin suppression by 33%, the coated lenses being more efficient than tinted lenses.
Conclusions: All smartphones in this study emit radiant power in the short-wavelength region of the visible spectrum. Such smartphones may impair the regulation of circadian cycles at nighttime. The activation of night-mode functions was more efficient than the commercially available blue-light-reducing spectacle lenses in reducing the amount of short-wavelength light (up to 2.25 times). These results can be extrapolated to most electronic devices because they share the same type of white radiant sources with smartphones.
https://pubmed.ncbi.nlm.nih.gov/32168244/
Significance: Electronic display devices used before bed may negatively affect sleep quality through the effects of short-wavelength (blue) light on melatonin production and the circadian cycle. We quantified the efficacy of night-mode functions and blue-light-reducing lenses in ameliorating this problem.
Purpose: The purpose of this study was to compare the radiation produced by smartphones that reaches the eye when using night-mode functions or blue-light-reducing spectacle lenses.
Methods: Radiant flux of 64 smartphones was measured with an integrating sphere. The retinal illuminance was calculated from the radiant flux of the smartphones. For the night-mode functions, the spectra produced by the smartphones were measured. The transmittance of four blue-light-reducing spectacle lenses, which filter light with either antireflective coatings or tints, was measured using a spectrometer. To determine the impact of blue-light-reducing spectacles, the radiant flux of the smartphone was weighted by the transmission spectrum of these glasses. Visual and nonvisual (circadian) parameters were calculated to compute the melatonin suppression values (MSVs) through a logistic fitting of previously published data. The MSV was used as the figure of merit to evaluate the performance of blue-light spectacles and smartphone night-mode functions.
Results: Night-mode functions in smartphones reduced MSVs by up to 93%. The warmest mode produced the least suppression. Blue-light-reducing spectacles reduced melatonin suppression by 33%, the coated lenses being more efficient than tinted lenses.
Conclusions: All smartphones in this study emit radiant power in the short-wavelength region of the visible spectrum. Such smartphones may impair the regulation of circadian cycles at nighttime. The activation of night-mode functions was more efficient than the commercially available blue-light-reducing spectacle lenses in reducing the amount of short-wavelength light (up to 2.25 times). These results can be extrapolated to most electronic devices because they share the same type of white radiant sources with smartphones.
https://pubmed.ncbi.nlm.nih.gov/32168244/
The inner clock-Blue light sets the human rhythm
J Biophotonics. 2019 Dec;12(12):e201900102. doi: 10.1002/jbio.201900102. Epub 2019 Sep 2.Siegfried Wahl, Moritz Engelhardt, Patrick Schaupp, Christian Lappe, Iliya V IvanovPMID: 31433569 / PMCID: PMC7065627 / DOI: 10.1002/jbio.201900102
The blue light is the strongest synchronising agent for the circadian rhythm, which keeps most biological and psychological rhythms internally synchronised. The beneficial effect on the circadian rhythm, sleep quality,...
The inner clock-Blue light sets the human rhythm
The blue light is the strongest synchronising agent for the circadian rhythm, which keeps most biological and psychological rhythms internally synchronised. The beneficial effect on the circadian rhythm, sleep quality, mood and cognitive performance depends not only on the light spectral composition but also on the time of exposure and its intensity. Exposure to blue light during the day is important for suppressing the secretion of melatonin, the hormone (signal substance) produced by the pineal gland that plays a crucial role in the circadian rhythm. While exposure to blue light is important for maintaining well-being, alertness and cognitive performance during the daytime, chronic exposure to blue light immediately before bed can have serious consequences for sleep quality, circadian rhythm and cycle length.
The inner clock-Blue light sets the human rhythm
J Biophotonics. 2019 Dec;12(12):e201900102. doi: 10.1002/jbio.201900102. Epub 2019 Sep 2.
PMID: 31433569 / PMCID: PMC7065627 / DOI: 10.1002/jbio.201900102
Abstract
Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep-wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low-intensity blue light directly before bedtime, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness, and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing.
https://pubmed.ncbi.nlm.nih.gov/31433569/
Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep-wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low-intensity blue light directly before bedtime, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness, and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing.
https://pubmed.ncbi.nlm.nih.gov/31433569/
Ocular and systemic melatonin and the influence of light exposure
Clin Exp Optom. 2019 Mar;102(2):99-108. doi: 10.1111/cxo.12824. Epub 2018 Aug 3.Lisa A OstrinPMID: 30074278 / DOI: 10.1111/cxo.12824
Melatonin is a neurohormone (signalling substance) known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland are strongly influenced...
Ocular and systemic melatonin and the influence of light exposure
Melatonin is a neurohormone (signalling substance) known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland are strongly influenced by light stimulation of the retina, particularly through the intrinsic photosensitive retinal ganglion cells. These include light exposure and photoreceptor contributions to melatonin suppression, leading to considerations of how sleep glasses, cataracts, and light therapy may affect sleep and mood in patients. In addition, the interactions between melatonin, sleep and the development of refractive errors are discussed.
Ocular and systemic melatonin and the influence of light exposure
Clin Exp Optom. 2019 Mar;102(2):99-108. doi: 10.1111/cxo.12824. Epub 2018 Aug 3.
PMID: 30074278 / DOI: 10.1111/cxo.12824
Abstract
Melatonin is a neurohormone known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland is heavily influenced by light stimulation of the retina, particularly through the intrinsically photosensitive retinal ganglion cells. Melatonin is also synthesised within the eye, although to a much lesser extent than in the pineal gland. Melatonin acts directly on ocular structures to mediate a variety of diurnal rhythms and physiological processes within the eye. The interactions between melatonin, the eye, and visual function have been the subject of a considerable body of recent research. This review is intended to provide a broad introduction for eye-care practitioners and researchers to the topic of melatonin and the eye. The first half of the review describes the anatomy and physiology of melatonin production: how visual inputs affect the pineal production of melatonin; how melatonin is involved in a variety of diurnal rhythms within the eye, including photoreceptor disc shedding, neuronal sensitivity, and intraocular pressure control; and melatonin production and physiological roles in retina, ciliary body, lens and cornea. The second half of the review describes clinical implications of light/melatonin interactions. These include light exposure and photoreceptor contributions in melatonin suppression, leading to consideration of how blue blockers, cataract, and light therapy might affect sleep and mood in patients. Additionally, the interactions between melatonin, sleep and refractive error development are discussed. A better understanding of environmental factors that affect melatonin and subsequent effects on physiological processes will allow clinicians to develop treatments and recommend modifiable behaviours to improve sleep, increase daytime alertness, and regulate ocular and systemic processes related to melatonin.
https://pubmed.ncbi.nlm.nih.gov/30074278/
Melatonin is a neurohormone known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland is heavily influenced by light stimulation of the retina, particularly through the intrinsically photosensitive retinal ganglion cells. Melatonin is also synthesised within the eye, although to a much lesser extent than in the pineal gland. Melatonin acts directly on ocular structures to mediate a variety of diurnal rhythms and physiological processes within the eye. The interactions between melatonin, the eye, and visual function have been the subject of a considerable body of recent research. This review is intended to provide a broad introduction for eye-care practitioners and researchers to the topic of melatonin and the eye. The first half of the review describes the anatomy and physiology of melatonin production: how visual inputs affect the pineal production of melatonin; how melatonin is involved in a variety of diurnal rhythms within the eye, including photoreceptor disc shedding, neuronal sensitivity, and intraocular pressure control; and melatonin production and physiological roles in retina, ciliary body, lens and cornea. The second half of the review describes clinical implications of light/melatonin interactions. These include light exposure and photoreceptor contributions in melatonin suppression, leading to consideration of how blue blockers, cataract, and light therapy might affect sleep and mood in patients. Additionally, the interactions between melatonin, sleep and refractive error development are discussed. A better understanding of environmental factors that affect melatonin and subsequent effects on physiological processes will allow clinicians to develop treatments and recommend modifiable behaviours to improve sleep, increase daytime alertness, and regulate ocular and systemic processes related to melatonin.
https://pubmed.ncbi.nlm.nih.gov/30074278/
Restricting short-wavelength light in the evening to improve sleep in recreational athletes - A pilot study
Epub 2018 Nov 14. Jul;19(6):728-735. doi: 10.1080/17461391.2018.1544278. Melanie Knufinke, Lennart Fittkau-Koch, Els I S Møst, Michiel A J Kompier, Arne NieuwenhuysPMID: 30427265 / DOI: 10.1080/17461391.2018.1544278
The trial was to investigate whether blocking the blue light in the evening can promote sleep and potentially other sleep parameters among recovering athletes.
Restricting short-wavelength light in the evening to improve sleep in recreational athletes - A pilot study
The trial was to investigate whether blocking the blue light in the evening can promote sleep and potentially other sleep parameters among recovering athletes.
Restricting short-wavelength light in the evening to improve sleep in recreational athletes - A pilot study
Epub 2018 Nov 14. Jul;19(6):728-735. doi: 10.1080/17461391.2018.1544278.
PMID: 30427265 / DOI: 10.1080/17461391.2018.1544278
Abstract
Sleep is crucial for recovery and skill acquisition in athletes. Paradoxically, athletes often encounter difficulties initiating and maintaining sleep, while having sufficient sleep opportunity. Blue (short-wavelength) light as emitted by electronic screens is considered a potential sleep thief, as it suppresses habitual melatonin secretion. The current study sought to investigate whether blocking short-wavelength light in the evening can improve sleep onset latency and potentially other sleep parameters among recreational athletes. The study had a within-subject crossover design. Fifteen recreational athletes, aged between 18 and 32 years (12 females, 3 males), were randomly assigned to start the intervention period with either the light restriction condition (LR; amber-lens glasses), or the no-light restriction condition (nLR; transparent glasses). Sleep hygiene practices, actigraphy and diary-based sleep estimates were monitored during four consecutive nights within each condition. Sleep hygiene practices did not significantly differ between conditions. Results indicate that blocking short-wavelength light in the evening, as compared to habitual light exposure, significantly shortened subjective sleep onset latency (Δ = 7 min), improved sleep quality (Δ = 0.6; scale 1-10), and increased alertness the following morning. Actigraphy-based sleep estimates showed no significant differences between conditions. Blocking short-wavelength light in the evening by means of amber-lens glasses is a cost-efficient and promising means to improve subjective sleep estimates among recreational athletes in their habitual home environment. The relatively small effects of the current study may be strengthened by additionally increasing morning- and daytime light exposure and, potentially, by reducing the alerting effects of media use before bedtime.
https://pubmed.ncbi.nlm.nih.gov/30427265/
Sleep is crucial for recovery and skill acquisition in athletes. Paradoxically, athletes often encounter difficulties initiating and maintaining sleep, while having sufficient sleep opportunity. Blue (short-wavelength) light as emitted by electronic screens is considered a potential sleep thief, as it suppresses habitual melatonin secretion. The current study sought to investigate whether blocking short-wavelength light in the evening can improve sleep onset latency and potentially other sleep parameters among recreational athletes. The study had a within-subject crossover design. Fifteen recreational athletes, aged between 18 and 32 years (12 females, 3 males), were randomly assigned to start the intervention period with either the light restriction condition (LR; amber-lens glasses), or the no-light restriction condition (nLR; transparent glasses). Sleep hygiene practices, actigraphy and diary-based sleep estimates were monitored during four consecutive nights within each condition. Sleep hygiene practices did not significantly differ between conditions. Results indicate that blocking short-wavelength light in the evening, as compared to habitual light exposure, significantly shortened subjective sleep onset latency (Δ = 7 min), improved sleep quality (Δ = 0.6; scale 1-10), and increased alertness the following morning. Actigraphy-based sleep estimates showed no significant differences between conditions. Blocking short-wavelength light in the evening by means of amber-lens glasses is a cost-efficient and promising means to improve subjective sleep estimates among recreational athletes in their habitual home environment. The relatively small effects of the current study may be strengthened by additionally increasing morning- and daytime light exposure and, potentially, by reducing the alerting effects of media use before bedtime.
https://pubmed.ncbi.nlm.nih.gov/30427265/
Blocking nocturnal blue light for insomnia: A randomized controlled trial
J Psychiatr Res. 2018 Jan:96:196-202. doi: 10.1016/j.jpsychires.2017.10.015. Epub 2017 Oct 21.Ari Shechter, Elijah Wookhyun Kim, Marie-Pierre St-Onge, Andrew J WestwoodPMID: 29101797 / PMCID: PMC5703049 / DOI: 10.1016/j.jpsychires.2017.10.015
The use of electronic devices with light displays before bedtime can cause or worsen sleep problems. Exposure to blue wavelength light, especially from these devices, can affect sleep by suppressing...
Blocking nocturnal blue light for insomnia: A randomized controlled trial
The use of electronic devices with light displays before bedtime can cause or worsen sleep problems. Exposure to blue wavelength light, especially from these devices, can affect sleep by suppressing melatonin and causing neurophysiological arousal. We wanted to determine whether wearing sleep glasses before bed improves sleep in people with insomnia. PIRS total scores and subscales for quality of life, sadness and sleep parameters were improved in sleep glasses versus clear lenses (p-values <0.05). Reported wake time was significantly delayed and mean subjective total sleep time (TST), overall quality and sound sleep were significantly higher (p-values <0.05) with the sleep glasses versus clear lens condition over the seven-day intervention period. Actigraphic measures for TST only were significantly higher with the sleep glasses versus clear lens condition (p = 0.035). Wearing amber versus clear lenses for two hours before bed for one week improved sleep in people with insomnia symptoms. These findings have health relevance given the widespread use of light-emitting devices before bedtime and the prevalence of insomnia. Sleep glasses represent a safe, affordable, and easily implemented therapeutic intervention for insomnia symptoms.
Blocking nocturnal blue light for insomnia: A randomized controlled trial
J Psychiatr Res. 2018 Jan:96:196-202. doi: 10.1016/j.jpsychires.2017.10.015. Epub 2017 Oct 21.
PMID: 29101797 / PMCID: PMC5703049 / DOI: 10.1016/j.jpsychires.2017.10.015
Abstract
The use of light-emitting electronic devices before bedtime may contribute to or exacerbate sleep problems. Exposure to blue-wavelength light in particular from these devices may affect sleep by suppressing melatonin and causing neurophysiologic arousal. We aimed to determine if wearing amber-tinted blue light-blocking lenses before bedtime improves sleep in individuals with insomnia. Fourteen individuals (n = 8 females; age ± SD 46.6 ± 11.5 y) with insomnia symptoms wore blue light-blocking amber lenses or clear placebo lenses in lightweight wraparound frames for 2 h immediately preceding bedtime for 7 consecutive nights in a randomized crossover trial (4-wk washout). Ambulatory sleep measures included the Pittsburgh Insomnia Rating Scale (PIRS) completed at the end of each intervention period, and daily post-sleep questionnaire and wrist-actigraphy. PIRS total scores, and Quality of Life, Distress, and Sleep Parameter subscales, were improved in amber vs. clear lenses condition (p-values <0.05). Reported wake-time was significantly delayed, and mean subjective total sleep time (TST), overall quality, and soundness of sleep were significantly higher (p-values <0.05) in amber vs. clear lenses condition over the 7-d intervention period. Actigraphic measures of TST only were significantly higher in amber vs. clear lenses condition (p = 0.035). Wearing amber vs. clear lenses for 2-h preceding bedtime for 1 week improved sleep in individuals with insomnia symptoms. These findings have health relevance given the broad use of light-emitting devices before bedtime and prevalence of insomnia. Amber lenses represent a safe, affordable, and easily implemented therapeutic intervention for insomnia symptoms.
https://pubmed.ncbi.nlm.nih.gov/29101797/
The use of light-emitting electronic devices before bedtime may contribute to or exacerbate sleep problems. Exposure to blue-wavelength light in particular from these devices may affect sleep by suppressing melatonin and causing neurophysiologic arousal. We aimed to determine if wearing amber-tinted blue light-blocking lenses before bedtime improves sleep in individuals with insomnia. Fourteen individuals (n = 8 females; age ± SD 46.6 ± 11.5 y) with insomnia symptoms wore blue light-blocking amber lenses or clear placebo lenses in lightweight wraparound frames for 2 h immediately preceding bedtime for 7 consecutive nights in a randomized crossover trial (4-wk washout). Ambulatory sleep measures included the Pittsburgh Insomnia Rating Scale (PIRS) completed at the end of each intervention period, and daily post-sleep questionnaire and wrist-actigraphy. PIRS total scores, and Quality of Life, Distress, and Sleep Parameter subscales, were improved in amber vs. clear lenses condition (p-values <0.05). Reported wake-time was significantly delayed, and mean subjective total sleep time (TST), overall quality, and soundness of sleep were significantly higher (p-values <0.05) in amber vs. clear lenses condition over the 7-d intervention period. Actigraphic measures of TST only were significantly higher in amber vs. clear lenses condition (p = 0.035). Wearing amber vs. clear lenses for 2-h preceding bedtime for 1 week improved sleep in individuals with insomnia symptoms. These findings have health relevance given the broad use of light-emitting devices before bedtime and prevalence of insomnia. Amber lenses represent a safe, affordable, and easily implemented therapeutic intervention for insomnia symptoms.
https://pubmed.ncbi.nlm.nih.gov/29101797/
Attenuation of short wavelengths alters sleep and the ipRGC pupil response
Ophthalmic Physiol Opt. 2017 Jul;37(4):440-450. doi: 10.1111/opo.12385.Lisa A Ostrin, Kaleb S Abbott, Hope M QueenerPMID: 28656675 / PMCID: PMC7229994 / DOI: 10.1111/opo.12385
This experiment was to investigate whether melatonin level and sleep quality can be changed by reducing the night time signal to the ipRGCs, using sleep glasses. The experiment showed that...
Attenuation of short wavelengths alters sleep and the ipRGC pupil response
This experiment was to investigate whether melatonin level and sleep quality can be changed by reducing the night time signal to the ipRGCs, using sleep glasses. The experiment showed that night-time sleep glasses increased subjectively measured sleep quality and objectively measured melatonin levels and sleep duration. This was probably due to reduced nighttime stimulation of ipRGCs. Changes in the ipRGC-driven pupillary response suggest a change in the circadian rhythm. The findings suggest that minimising blue light after sunset may help regulate sleep patterns.
Attenuation of short wavelengths alters sleep and the ipRGC pupil response
Ophthalmic Physiol Opt. 2017 Jul;37(4):440-450. doi: 10.1111/opo.12385.
PMID: 28656675 / PMCID: PMC7229994 / DOI: 10.1111/opo.12385
Abstract
Purpose: Exposure to increasing amounts of artificial light during the night may contribute to the high prevalence of reported sleep dysfunction. Release of the sleep hormone melatonin is mediated by the intrinsically photosensitive retinal ganglion cells (ipRGCs). This study sought to investigate whether melatonin level and sleep quality can be modulated by decreasing night-time input to the ipRGCs.
Methods: Subjects (ages 17-42, n = 21) wore short wavelength-blocking glasses prior to bedtime for 2 weeks. The ipRGC-mediated post illumination pupil response was measured before and after the experimental period. Stimulation was presented with a ganzfeld stimulator, including one-second and five-seconds of long and short wavelength light, and the pupil was imaged with an infrared camera. Pupil diameter was measured before, during and for 60 s following stimulation, and the six-second and 30 s post illumination pupil response and area under the curve following light offset were determined. Subjects wore an actigraph device for objective measurements of activity, light exposure, and sleep. Saliva samples were collected to assess melatonin content. The Pittsburgh Sleep Quality Index (PSQI) was administered to assess subjective sleep quality.
Results: Subjects wore the blue-blocking glasses 3:57 ± 1:03 h each night. After the experimental period, the pupil showed a slower redilation phase, resulting in a significantly increased 30 s post illumination pupil response to one-second short wavelength light, and decreased area under the curve for one and five-second short wavelength light, when measured at the same time of day as baseline. Night time melatonin increased from 16.1 ± 7.5 pg mL-1 to 25.5 ± 10.7 pg mL-1 (P < 0.01). Objectively measured sleep duration increased 24 min, from 408.7 ± 44.9 to 431.5 ± 42.9 min (P < 0.001). Mean PSQI score improved from 5.6 ± 2.9 to 3.0 ± 2.2.
Conclusions: The use of short wavelength-blocking glasses at night increased subjectively measured sleep quality and objectively measured melatonin levels and sleep duration, presumably as a result of decreased night-time stimulation of ipRGCs. Alterations in the ipRGC-driven pupil response suggest a shift in circadian phase. Results suggest that minimising short wavelength light following sunset may help in regulating sleep patterns.
Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison
J Psychiatr Res. 2017 Apr:87:61-70. doi: 10.1016/j.jpsychires.2016.12.010. Epub 2016 Dec 12.Jung-Yoon Heo, Kiwon Kim, Maurizio Fava, David Mischoulon, George I Papakostas, Min-Ji Kim, Dong Jun Kim, Kyung-Ah Judy Chang, Yunhye Oh 1, Bum-Hee Yu, Hong Jin JeonPMID: 28017916 / DOI: 10.1016/j.jpsychires.2016.12.010
Smartphones emit light to users through LED (Light-Emitting Diode) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of VRF blue...
Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison
Smartphones emit light to users through LED (Light-Emitting Diode) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of VRF blue light LED on humans at night. Among the trial's 22 participants, who were each hospitalised twice, blue light smartphone use was associated with significantly reduced sleepiness and increased confusion. Smartphone users also experienced longer onset of melatonin production in the brain and experienced increases in body temperature, serum melatonin levels and cortisol levels, although these changes were not statistically significant. Using blue light LED smartphones at night may have a negative impact on sleep and confusional state, although it may not be enough to lead to significant changes in serum melatonin and cortisol levels.
Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison
J Psychiatr Res. 2017 Apr:87:61-70. doi: 10.1016/j.jpsychires.2016.12.010. Epub 2016 Dec 12.
PMID: 28017916 / DOI: 10.1016/j.jpsychires.2016.12.010
Abstract
Smartphones deliver light to users through Light Emitting Diode (LED) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of smartphone blue light LED on humans at night. We investigated changes in serum melatonin levels, cortisol levels, body temperature, and psychiatric measures with a randomized, double-blind, cross-over, placebo-controlled design of two 3-day admissions. Each subject played smartphone games with either conventional LED or suppressed blue light from 7:30 to 10:00PM (150 min). Then, they were readmitted and conducted the same procedure with the other type of smartphone. Serum melatonin levels were measured in 60-min intervals before, during and after use of the smartphones. Serum cortisol levels and body temperature were monitored every 120 min. The Profile of Mood States (POMS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and auditory and visual Continuous Performance Tests (CPTs) were administered. Among the 22 participants who were each admitted twice, use of blue light smartphones was associated with significantly decreased sleepiness (Cohen's d = 0.49, Z = 43.50, p = 0.04) and confusion-bewilderment (Cohen's d = 0.53, Z = 39.00, p = 0.02), and increased commission error (Cohen's d = -0.59, t = -2.64, p = 0.02). Also, users of blue light smartphones experienced a longer time to reach dim light melatonin onset 50% (2.94 vs. 2.70 h) and had increases in body temperature, serum melatonin levels, and cortisol levels, although these changes were not statistically significant. Use of blue light LED smartphones at night may negatively influence sleep and commission errors, while it may not be enough to lead to significant changes in serum melatonin and cortisol levels.
https://pubmed.ncbi.nlm.nih.gov/28017916/
Smartphones deliver light to users through Light Emitting Diode (LED) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of smartphone blue light LED on humans at night. We investigated changes in serum melatonin levels, cortisol levels, body temperature, and psychiatric measures with a randomized, double-blind, cross-over, placebo-controlled design of two 3-day admissions. Each subject played smartphone games with either conventional LED or suppressed blue light from 7:30 to 10:00PM (150 min). Then, they were readmitted and conducted the same procedure with the other type of smartphone. Serum melatonin levels were measured in 60-min intervals before, during and after use of the smartphones. Serum cortisol levels and body temperature were monitored every 120 min. The Profile of Mood States (POMS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and auditory and visual Continuous Performance Tests (CPTs) were administered. Among the 22 participants who were each admitted twice, use of blue light smartphones was associated with significantly decreased sleepiness (Cohen's d = 0.49, Z = 43.50, p = 0.04) and confusion-bewilderment (Cohen's d = 0.53, Z = 39.00, p = 0.02), and increased commission error (Cohen's d = -0.59, t = -2.64, p = 0.02). Also, users of blue light smartphones experienced a longer time to reach dim light melatonin onset 50% (2.94 vs. 2.70 h) and had increases in body temperature, serum melatonin levels, and cortisol levels, although these changes were not statistically significant. Use of blue light LED smartphones at night may negatively influence sleep and commission errors, while it may not be enough to lead to significant changes in serum melatonin and cortisol levels.
https://pubmed.ncbi.nlm.nih.gov/28017916/
Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances
PLoS One. 2017 Jan 3;12(1):e0169114. doi: 10.1371/journal.pone.0169114. eCollection 2017.Tsz Wing Leung, Roger Wing-Hong Li, Chea-Su KeePMID: 28045969 / PMCID: PMC5207664 / DOI: 10.1371/journal.pone.0169114
The trial will assess the optical performance and effect of sleep glasses, as well as investigate whether a reduction in blue light affects visible performance and sleep quality. The conclusion...
Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances
The trial will assess the optical performance and effect of sleep glasses, as well as investigate whether a reduction in blue light affects visible performance and sleep quality. The conclusion shows that sleep glasses can partially filter high-energy light with short wavelengths without impairing visual performance and sleep quality. Sleep glasses can act as a supplement to protect the retina from blue light.
Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances
PLoS One. 2017 Jan 3;12(1):e0169114. doi: 10.1371/journal.pone.0169114. eCollection 2017.
PMID: 28045969 / PMCID: PMC5207664 / DOI: 10.1371/journal.pone.0169114
Abstract
Purposes: To evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality.
Methods: Experiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18-30 yrs, middle-aged adults: 40-55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire.
Results: All tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR-BT [-0.05, 0.05]; AR-BF [-0.05, 0.06]; BT-BF [-0.06, 0.06]) or without glare (95% CI: AR-BT [-0.01, 0.03]; AR-BF [-0.01, 0.03]; BT-BF [-0.02, 0.02]) and colour discrimination (95% CI: AR-BT [-9.07, 1.02]; AR-BF [-7.06, 4.46]; BT-BF [-3.12, 8.57]).
Conclusion: Blue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential blue-light hazard.
https://pubmed.ncbi.nlm.nih.gov/28045969/
Purposes: To evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality.
Methods: Experiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18-30 yrs, middle-aged adults: 40-55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire.
Results: All tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR-BT [-0.05, 0.05]; AR-BF [-0.05, 0.06]; BT-BF [-0.06, 0.06]) or without glare (95% CI: AR-BT [-0.01, 0.03]; AR-BF [-0.01, 0.03]; BT-BF [-0.02, 0.02]) and colour discrimination (95% CI: AR-BT [-9.07, 1.02]; AR-BF [-7.06, 4.46]; BT-BF [-3.12, 8.57]).
Conclusion: Blue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential blue-light hazard.
https://pubmed.ncbi.nlm.nih.gov/28045969/
Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors
J Physiol Paris. 2016 Nov;110(4 Pt B):467-479. doi: 10.1016/j.jphysparis.2017.05.001. Epub 2017 May 12.Yvan Touitou, David Touitou, Alain ReinbergPMID: 28487255 / DOI: 10.1016/j.jphysparis.2017.05.001
If teenagers spend more time online they are exposed to health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles...), all of which are negatively associated with...
Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors
If teenagers spend more time online they are exposed to health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles...), all of which are negatively associated with bodily functionality during the day and sleep quality. Adolescent sleep becomes irregular, shortened and delayed compared to later onset of sleep and early awakening due to early school start times on weekdays. This results in desynchronisation of the circadian rhythm and loss of sleep. Furthermore, it has become a matter of great concern that young people are exposed to many electronic devices before bed, because LEDs in the devices emit much more blue light than white incandescent bulbs and compact fluorescent tubes and therefore have a greater influence on the biological clock.
Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors
J Physiol Paris. 2016 Nov;110(4 Pt B):467-479. doi: 10.1016/j.jphysparis.2017.05.001. Epub 2017 May 12.
PMID: 28487255 / DOI: 10.1016/j.jphysparis.2017.05.001
Abstract
Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock. A large number of adolescents move to evening chronotype and experience a misalignment between biological and social rhythms which, added to sleep loss, results in e.g. fatigue, daytime sleepiness, behavioral problems and poor academic achievement. This paper on adolescent circadian disruption will review the sensitivity of adolescents to light including LEDs with the effects on the circadian system, the crosstalk between the clock and the pineal gland, the role of melatonin, and the behavior of some adolescents(media use, alcohol consumption, binge drinking, smoking habits, stimulant use…). Lastly, some practical recommendations and perspectives are put forward. The permanent social jet lag resulting in clock misalignment experienced by a number of adolescents should be considered as a matter of public health.
https://pubmed.ncbi.nlm.nih.gov/28487255/
Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock. A large number of adolescents move to evening chronotype and experience a misalignment between biological and social rhythms which, added to sleep loss, results in e.g. fatigue, daytime sleepiness, behavioral problems and poor academic achievement. This paper on adolescent circadian disruption will review the sensitivity of adolescents to light including LEDs with the effects on the circadian system, the crosstalk between the clock and the pineal gland, the role of melatonin, and the behavior of some adolescents(media use, alcohol consumption, binge drinking, smoking habits, stimulant use…). Lastly, some practical recommendations and perspectives are put forward. The permanent social jet lag resulting in clock misalignment experienced by a number of adolescents should be considered as a matter of public health.
https://pubmed.ncbi.nlm.nih.gov/28487255/
Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial
Chronobiol Int. 2016;33(8):1037-44. doi: 10.1080/07420528.2016.1194289. Epub 2016 Jun 20.Yuichi Esaki, Tsuyoshi Kitajima, Yasuhiro Ito, Shigefumi Koike, Yasumi Nakao, Akiko Tsuchiya, Marina Hirose, Nakao IwataPMID: 27322730 / DOI: 10.1080/07420528.2016.1194289
We investigated the effect of sleep glasses in people with delayed sleep phase disorder (DSPD). The patients who used sleep glasses showed a 78-minute advance in DLMO value, although the...
Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial
We investigated the effect of sleep glasses in people with delayed sleep phase disorder (DSPD). The patients who used sleep glasses showed a 78-minute advance in DLMO value, although the change was not statistically significant. Nevertheless, sleep onset time measured by actigraph was advanced by 132 minutes after treatment. These data suggest that wearing sleep glasses may be an effective and safe treatment for patients with DSPD.
Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial
Chronobiol Int. 2016;33(8):1037-44. doi: 10.1080/07420528.2016.1194289. Epub 2016 Jun 20.
PMID: 27322730 / DOI: 10.1080/07420528.2016.1194289
Abstract
It has been recently discovered that blue wavelengths form the portion of the visible electromagnetic spectrum that most potently regulates circadian rhythm. We investigated the effect of blue light-blocking glasses in subjects with delayed sleep phase disorder (DSPD). This open-label trial was conducted over 4 consecutive weeks. The DSPD patients were instructed to wear blue light-blocking amber glasses from 21:00 p.m. to bedtime, every evening for 2 weeks. To ascertain the outcome of this intervention, we measured dim light melatonin onset (DLMO) and actigraphic sleep data at baseline and after the treatment. Nine consecutive DSPD patients participated in this study. Most subjects could complete the treatment with the exception of one patient who hoped for changing to drug therapy before the treatment was completed. The patients who used amber lens showed an advance of 78 min in DLMO value, although the change was not statistically significant (p = 0.145). Nevertheless, the sleep onset time measured by actigraph was advanced by 132 min after the treatment (p = 0.034). These data suggest that wearing amber lenses may be an effective and safe intervention for the patients with DSPD. These findings also warrant replication in a larger patient cohort with controlled observations.
https://pubmed.ncbi.nlm.nih.gov/27322730/
It has been recently discovered that blue wavelengths form the portion of the visible electromagnetic spectrum that most potently regulates circadian rhythm. We investigated the effect of blue light-blocking glasses in subjects with delayed sleep phase disorder (DSPD). This open-label trial was conducted over 4 consecutive weeks. The DSPD patients were instructed to wear blue light-blocking amber glasses from 21:00 p.m. to bedtime, every evening for 2 weeks. To ascertain the outcome of this intervention, we measured dim light melatonin onset (DLMO) and actigraphic sleep data at baseline and after the treatment. Nine consecutive DSPD patients participated in this study. Most subjects could complete the treatment with the exception of one patient who hoped for changing to drug therapy before the treatment was completed. The patients who used amber lens showed an advance of 78 min in DLMO value, although the change was not statistically significant (p = 0.145). Nevertheless, the sleep onset time measured by actigraph was advanced by 132 min after the treatment (p = 0.034). These data suggest that wearing amber lenses may be an effective and safe intervention for the patients with DSPD. These findings also warrant replication in a larger patient cohort with controlled observations.
https://pubmed.ncbi.nlm.nih.gov/27322730/
Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices - Adverse Sleep Properties and Preventative Strategies
Front Public Health. 2015 Oct 13:3:233. doi: 10.3389/fpubh.2015.00233. eCollection 2015.Paul Gringras, Benita Middleton, Debra J Skene, Victoria L RevellPMID: 26528465 / PMCID: PMC4602096 / DOI: 10.3389/fpubh.2015.00233
Screens often emit significant amounts of very blue light, which can negatively affect sleep. We investigated the extent of light scattering using a tablet (iPad Air), e-reader (Kindle Paperwhite 1st...
Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices - Adverse Sleep Properties and Preventative Strategies
Screens often emit significant amounts of very blue light, which can negatively affect sleep. We investigated the extent of light scattering using a tablet (iPad Air), e-reader (Kindle Paperwhite 1st generation) and smartphone (iPhone 5s), all of which emit blue light. We also wanted to assess the impact of strategies designed to reduce these light spills. The first strategy was using a pair of sleep glasses. The second strategy was using an app designed to reduce the amount of blue light in the evening. Both the sleep glasses and the app significantly reduced the light scattering of blue light. As this type of light is likely to cause the most disruption to sleep as it effectively suppresses melatonin levels and increases alertness, there must be recognition that "brighter and bluer" at night is not synonymous with "better".
Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices - Adverse Sleep Properties and Preventative Strategies
Front Public Health. 2015 Oct 13:3:233. doi: 10.3389/fpubh.2015.00233. eCollection 2015.
PMID: 26528465 / PMCID: PMC4602096 / DOI: 10.3389/fpubh.2015.00233
Abstract
Objective: In an effort to enhance the efficiency, brightness, and contrast of light-emitting (LE) devices during the day, displays often generate substantial short-wavelength (blue-enriched) light emissions that can adversely affect sleep. We set out to verify the extent of such short-wavelength emissions, produced by a tablet (iPad Air), e-reader (Kindle Paperwhite 1st generation), and smartphone (iPhone 5s) and to determine the impact of strategies designed to reduce these light emissions.
Setting: University of Surrey dedicated chronobiology facility.
Methods: First, the spectral power of all the LE devices was assessed when displaying identical text. Second, we compared the text output with that of "Angry Birds" - a popular top 100 "App Store" game. Finally, we measured the impact of two strategies that attempt to reduce the output of short-wavelength light emissions. The first strategy employed an inexpensive commercially available pair of orange-tinted "blue-blocking" glasses. The second strategy tested an app designed to be "sleep-aware" whose designers deliberately attempted to reduce short-wavelength light emissions.
Results: All the LE devices shared very similar enhanced short-wavelength peaks when displaying text. This included the output from the backlit Kindle Paperwhite device. The spectra when comparing text to the Angry Birds game were also very similar, although the text emissions were higher intensity. Both the orange-tinted glasses and the "sleep-aware" app significantly reduced short-wavelength emissions.
Conclusion: The LE devices tested were all bright and characterized by short-wavelength enriched emissions. Since this type of light is likely to cause the most disruption to sleep as it most effectively suppresses melatonin and increases alertness, there needs to be the recognition that at night-time "brighter and bluer" is not synonymous with "better." Ideally future software design could be better optimized when night-time use is anticipated, and hardware should allow an automatic "bedtime mode" that shifts blue and green light emissions to yellow and red as well as reduce backlight/light intensity.
https://pubmed.ncbi.nlm.nih.gov/26528465/
Objective: In an effort to enhance the efficiency, brightness, and contrast of light-emitting (LE) devices during the day, displays often generate substantial short-wavelength (blue-enriched) light emissions that can adversely affect sleep. We set out to verify the extent of such short-wavelength emissions, produced by a tablet (iPad Air), e-reader (Kindle Paperwhite 1st generation), and smartphone (iPhone 5s) and to determine the impact of strategies designed to reduce these light emissions.
Setting: University of Surrey dedicated chronobiology facility.
Methods: First, the spectral power of all the LE devices was assessed when displaying identical text. Second, we compared the text output with that of "Angry Birds" - a popular top 100 "App Store" game. Finally, we measured the impact of two strategies that attempt to reduce the output of short-wavelength light emissions. The first strategy employed an inexpensive commercially available pair of orange-tinted "blue-blocking" glasses. The second strategy tested an app designed to be "sleep-aware" whose designers deliberately attempted to reduce short-wavelength light emissions.
Results: All the LE devices shared very similar enhanced short-wavelength peaks when displaying text. This included the output from the backlit Kindle Paperwhite device. The spectra when comparing text to the Angry Birds game were also very similar, although the text emissions were higher intensity. Both the orange-tinted glasses and the "sleep-aware" app significantly reduced short-wavelength emissions.
Conclusion: The LE devices tested were all bright and characterized by short-wavelength enriched emissions. Since this type of light is likely to cause the most disruption to sleep as it most effectively suppresses melatonin and increases alertness, there needs to be the recognition that at night-time "brighter and bluer" is not synonymous with "better." Ideally future software design could be better optimized when night-time use is anticipated, and hardware should allow an automatic "bedtime mode" that shifts blue and green light emissions to yellow and red as well as reduce backlight/light intensity.
https://pubmed.ncbi.nlm.nih.gov/26528465/
Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers
J Adolesc Health. 2015 Jan;56(1):113-9. doi: 10.1016/j.jadohealth.2014.08.002. Epub 2014 Oct 3.Stéphanie van der Lely, Silvia Frey, Corrado Garbazza, Anna Wirz-Justice, Oskar G Jenni, Roland Steiner, Stefan Wolf, Christian Cajochen, Vivien Bromundt, Christina SchmidtPMID: 25287985 / DOI: 10.1016/j.jadohealth.2014.08.002
We investigated whether the use of sleep glasses in the evening while sitting in front of a computer screen (LED) favours sleep-promoting mechanisms at the subjective, cognitive and physiological levels....
Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers
We investigated whether the use of sleep glasses in the evening while sitting in front of a computer screen (LED) favours sleep-promoting mechanisms at the subjective, cognitive and physiological levels. Compared with clear lenses, sleep glasses significantly attenuated LED-induced melatonin suppression in the evening and decreased vigilance and subjective vigilance before bedtime. Visually scored sleep stages and behavioural measures collected the following morning were not changed. Conclusions: Sleep glasses may be useful in young people to protect against light exposure from LED screens and therefore potentially inhibit the negative effects modern lighting imposes on circadian physiology in the evening.
Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers
J Adolesc Health. 2015 Jan;56(1):113-9. doi: 10.1016/j.jadohealth.2014.08.002. Epub 2014 Oct 3.
PMID: 25287985 / DOI: 10.1016/j.jadohealth.2014.08.002
Abstract
Purpose: Adolescents prefer sleep and wake times that are considerably delayed compared with younger children or adults. Concomitantly, multimedia use in the evening is prevalent among teenagers and involves light exposure, particularly in the blue-wavelength range to which the biological clock and its associated arousal promotion system is the most sensitive. We investigated whether the use of blue light-blocking glasses (BB) during the evening, while sitting in front of a light-emitting diode (LED) computer screen, favors sleep initiating mechanisms at the subjective, cognitive, and physiological level.
Methods: The ambulatory part of the study comprised 2 weeks during which the sleep-wake cycle, evening light exposure, and multimedia screen use were monitored in thirteen 15- to 17-year-old healthy male volunteers. BB or clear lenses as control glasses were worn in a counterbalanced crossover design for 1 week each, during the evening hours while using LED screens. Afterward, participants entered the laboratory and underwent an evening blue light-enriched LED screen exposure during which they wore the same glasses as during the preceding week. Salivary melatonin, subjective sleepiness, and vigilant attention were regularly assayed, and subsequent sleep was recorded by polysomnography.
Results: Compared with clear lenses, BB significantly attenuated LED-induced melatonin suppression in the evening and decreased vigilant attention and subjective alertness before bedtime. Visually scored sleep stages and behavioral measures collected the morning after were not modified.
Conclusions: BB glasses may be useful in adolescents as a countermeasure for alerting effects induced by light exposure through LED screens and therefore potentially impede the negative effects modern lighting imposes on circadian physiology in the evening.
https://pubmed.ncbi.nlm.nih.gov/25287985/
Purpose: Adolescents prefer sleep and wake times that are considerably delayed compared with younger children or adults. Concomitantly, multimedia use in the evening is prevalent among teenagers and involves light exposure, particularly in the blue-wavelength range to which the biological clock and its associated arousal promotion system is the most sensitive. We investigated whether the use of blue light-blocking glasses (BB) during the evening, while sitting in front of a light-emitting diode (LED) computer screen, favors sleep initiating mechanisms at the subjective, cognitive, and physiological level.
Methods: The ambulatory part of the study comprised 2 weeks during which the sleep-wake cycle, evening light exposure, and multimedia screen use were monitored in thirteen 15- to 17-year-old healthy male volunteers. BB or clear lenses as control glasses were worn in a counterbalanced crossover design for 1 week each, during the evening hours while using LED screens. Afterward, participants entered the laboratory and underwent an evening blue light-enriched LED screen exposure during which they wore the same glasses as during the preceding week. Salivary melatonin, subjective sleepiness, and vigilant attention were regularly assayed, and subsequent sleep was recorded by polysomnography.
Results: Compared with clear lenses, BB significantly attenuated LED-induced melatonin suppression in the evening and decreased vigilant attention and subjective alertness before bedtime. Visually scored sleep stages and behavioral measures collected the morning after were not modified.
Conclusions: BB glasses may be useful in adolescents as a countermeasure for alerting effects induced by light exposure through LED screens and therefore potentially impede the negative effects modern lighting imposes on circadian physiology in the evening.
https://pubmed.ncbi.nlm.nih.gov/25287985/
The effects of chronotype, sleep schedule and light/dark pattern exposures on circadian phase
Sleep Med. 2014 Dec;15(12):1554-64. doi: 10.1016/j.sleep.2014.07.009. Epub 2014 Sep 3.Mariana G Figueiro, Barbara Plitnick, Mark S ReaPMID: 25441745 / PMCID: PMC8722381 / DOI: 10.1016/j.sleep.2014.07.009
The experiment aimed to clarify whether early and late chronotypes respond differently to controlled advancing and delaying patterns of light exposure while on a fixed, advanced sleep/wake schedule. In the...
The effects of chronotype, sleep schedule and light/dark pattern exposures on circadian phase
The experiment aimed to clarify whether early and late chronotypes respond differently to controlled advancing and delaying patterns of light exposure while on a fixed, advanced sleep/wake schedule. In the advanced light exposure pattern, participants received blue light in the morning and sleep glasses in the evening. In the delayed light exposure pattern, participants received sleep glasses in the morning and short-wavelength light in the evening.
The results show that changes of the circadian phase due to light intervention are consistent with those predicted by previously published phase response curves (PRCs) for both early and late chronotypes.
The effects of chronotype, sleep schedule and light/dark pattern exposures on circadian phase
Sleep Med. 2014 Dec;15(12):1554-64. doi: 10.1016/j.sleep.2014.07.009. Epub 2014 Sep 3.
PMID: 25441745 / PMCID: PMC8722381 / DOI: 10.1016/j.sleep.2014.07.009
Abstract
Background: Chronotype characterizes individual differences in sleep/wake rhythm timing, which can also impact light exposure patterns. The present study investigated whether early and late chronotypes respond differently to controlled advancing and delaying light exposure patterns while on a fixed, advanced sleep/wake schedule.
Methods: In a mixed design, 23 participants (11 late chronotypes and 12 early chronotypes) completed a 2-week, advanced sleep/wake protocol twice, once with an advancing light exposure pattern and once with a delaying light exposure pattern. In the advancing light exposure pattern, the participants received short-wavelength light in the morning and short-wavelength-restricting orange-tinted glasses in the evening. In the delaying light exposure pattern, participants received short-wavelength-restricting orange-tinted glasses in the morning and short-wavelength light in the evening. Light/dark exposures were measured with the Daysimeter. Salivary dim light melatonin onset (DLMO) was also measured.
Results: Compared to the baseline week, DLMO was significantly delayed after the delaying light intervention and significantly advanced after the advancing light intervention in both groups. There was no significant difference in how the two chronotype groups responded to the light intervention.
Conclusions: The present results demonstrate that circadian phase changes resulting from light interventions are consistent with those predicted by previously published phase response curves (PRCs) for both early and late chronotypes.
https://pubmed.ncbi.nlm.nih.gov/25441745/
Background: Chronotype characterizes individual differences in sleep/wake rhythm timing, which can also impact light exposure patterns. The present study investigated whether early and late chronotypes respond differently to controlled advancing and delaying light exposure patterns while on a fixed, advanced sleep/wake schedule.
Methods: In a mixed design, 23 participants (11 late chronotypes and 12 early chronotypes) completed a 2-week, advanced sleep/wake protocol twice, once with an advancing light exposure pattern and once with a delaying light exposure pattern. In the advancing light exposure pattern, the participants received short-wavelength light in the morning and short-wavelength-restricting orange-tinted glasses in the evening. In the delaying light exposure pattern, participants received short-wavelength-restricting orange-tinted glasses in the morning and short-wavelength light in the evening. Light/dark exposures were measured with the Daysimeter. Salivary dim light melatonin onset (DLMO) was also measured.
Results: Compared to the baseline week, DLMO was significantly delayed after the delaying light intervention and significantly advanced after the advancing light intervention in both groups. There was no significant difference in how the two chronotype groups responded to the light intervention.
Conclusions: The present results demonstrate that circadian phase changes resulting from light interventions are consistent with those predicted by previously published phase response curves (PRCs) for both early and late chronotypes.
https://pubmed.ncbi.nlm.nih.gov/25441745/
Controlling light-dark exposure patterns rather than sleep schedules determines circadian phase
Sleep Med. 2013 May;14(5):456-61. doi: 10.1016/j.sleep.2012.12.011. Epub 2013 Mar 6.Kenneth Appleman, Mariana G Figueiro, Mark S ReaPMID: 23481485 / PMCID: PMC4304650 / DOI: 10.1016/j.sleep.2012.12.011
The aim of the experiment was to investigate the displacement of the circadian rhythm based on two different light-dark exposure patterns. One pattern was congruent with a phase-advanced sleep schedule...
Controlling light-dark exposure patterns rather than sleep schedules determines circadian phase
The aim of the experiment was to investigate the displacement of the circadian rhythm based on two different light-dark exposure patterns. One pattern was congruent with a phase-advanced sleep schedule and one pattern was incongruent with an advanced schedule. After seven days on the 90-minute advanced sleep schedule, the circadian phase-advanced 132±19 minutes for the advance group (blue light) and delayed 59±7.5 minutes for the delay group (sleep glasses). Conclusions: Controlling the light-dark exposure pattern advances the circadian rhythm phase in the expected direction regardless of the fixed advanced sleep schedule.
Controlling light-dark exposure patterns rather than sleep schedules determines circadian phase
Sleep Med. 2013 May;14(5):456-61. doi: 10.1016/j.sleep.2012.12.011. Epub 2013 Mar 6.
PMID: 23481485 / PMCID: PMC4304650 / DOI: 10.1016/j.sleep.2012.12.011
Abstract
Objective: To examine, in a field study circadian phase changes associated with two different light-dark exposures patterns, one that was congruent with a phase advanced sleep schedule and one that was incongruent with an advanced schedule.
Methods: Twenty-one adults (mean age±standard deviation=22.5±3.9 years; 11 women) participated in the 12day study. After a five-day baseline period, participants were all given individualized, fixed, 90-minute advanced sleep schedules for one week. Participants were randomly assigned to one of two groups, an advance group with a light-dark exposure prescription designed to advance circadian phase or a delay group with light-dark exposure prescription designed to delay circadian phase. The advance group received two morning hours of short-wavelength (blue) light (λmax ≈ 476±1 nm, full-width-half-maximum ≈20 nm) exposure and three evening hours of light restriction (orange-filtered light, λ<525 nm=0). The delay group received blue light for three hours in the evening and light restriction for two hours in the morning. Participants led their normal lives while wearing a calibrated wrist-worn light exposure and activity monitor.
Results: After seven days on the 90-minute advanced sleep schedule, circadian phase advanced 132±19 minutes for the advance group and delayed 59±7.5 minutes for the delay group.
Conclusions: Controlling the light-dark exposure pattern shifts circadian phase in the expected direction irrespective of the fixed advanced sleep schedule.
https://pubmed.ncbi.nlm.nih.gov/23481485/
Objective: To examine, in a field study circadian phase changes associated with two different light-dark exposures patterns, one that was congruent with a phase advanced sleep schedule and one that was incongruent with an advanced schedule.
Methods: Twenty-one adults (mean age±standard deviation=22.5±3.9 years; 11 women) participated in the 12day study. After a five-day baseline period, participants were all given individualized, fixed, 90-minute advanced sleep schedules for one week. Participants were randomly assigned to one of two groups, an advance group with a light-dark exposure prescription designed to advance circadian phase or a delay group with light-dark exposure prescription designed to delay circadian phase. The advance group received two morning hours of short-wavelength (blue) light (λmax ≈ 476±1 nm, full-width-half-maximum ≈20 nm) exposure and three evening hours of light restriction (orange-filtered light, λ<525 nm=0). The delay group received blue light for three hours in the evening and light restriction for two hours in the morning. Participants led their normal lives while wearing a calibrated wrist-worn light exposure and activity monitor.
Results: After seven days on the 90-minute advanced sleep schedule, circadian phase advanced 132±19 minutes for the advance group and delayed 59±7.5 minutes for the delay group.
Conclusions: Controlling the light-dark exposure pattern shifts circadian phase in the expected direction irrespective of the fixed advanced sleep schedule.
https://pubmed.ncbi.nlm.nih.gov/23481485/
Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression
Appl Ergon. 2013 Mar;44(2):237-40. doi: 10.1016/j.apergo.2012.07.008. Epub 2012 Jul 31.Brittany Wood, Mark S Rea, Barbara Plitnick, Mariana G FigueiroPMID: 22850476 / DOI: 10.1016/j.apergo.2012.07.008
Exposure to light from screens may be associated with an increased risk of sleep disturbances because these devices emit blue light that dampens the production of melatonin. Subjects who used...
Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression
Exposure to light from screens may be associated with an increased risk of sleep disturbances because these devices emit blue light that dampens the production of melatonin. Subjects who used tablets with white light, subjects who used tablets with blue light with placebo glasses and subjects who used tablets with sleep glasses took part in the experiment. The suppression of melatonin production was greatest when using tablets with blue light.
Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression
Appl Ergon. 2013 Mar;44(2):237-40. doi: 10.1016/j.apergo.2012.07.008. Epub 2012 Jul 31.
PMID: 22850476 / DOI: 10.1016/j.apergo.2012.07.008
Abstract
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.
https://pubmed.ncbi.nlm.nih.gov/22850476/
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.
https://pubmed.ncbi.nlm.nih.gov/22850476/
Measuring circadian light and its impact on adolescents
Light Res Technol. 2011 Jun;43(2):201-215. doi: 10.1177/1477153510382853. Epub 2010 Oct 27.Mg Figueiro, Ja Brons, B Plitnick, B Donlan, Rp Leslie, Ms ReaPMID: 23504437 / PMCID: PMC3596177 / DOI: 10.1177/1477153510382853
Half of the students wore sleep glasses that minimised the shortwave light exposure necessary for circadian rhythm stimulation. A control group did not wear sleep glasses. The timing of the...
Measuring circadian light and its impact on adolescents
Half of the students wore sleep glasses that minimised the shortwave light exposure necessary for circadian rhythm stimulation. A control group did not wear sleep glasses. The timing of the circadian rhythm was significantly delayed for the students who wore sleep glasses compared to the control group. Sleep duration was slightly, but not significantly, limited in the sleep glasses group. Performance scores on a brief, standardised psychomotor alertness test and a self-report of well-being were not significantly different between the two groups.
Measuring circadian light and its impact on adolescents
Light Res Technol. 2011 Jun;43(2):201-215. doi: 10.1177/1477153510382853. Epub 2010 Oct 27.
PMID: 23504437 / PMCID: PMC3596177 / DOI: 10.1177/1477153510382853
Abstract
A field study was conducted with eighth-grade students to determine the impact of morning light on circadian timing, sleep duration and performance. Before and during school hours for a week in February 2009, half the students studied wore orange glasses that minimized short-wavelength light exposure needed for circadian system stimulation. A control group did not wear the orange glasses. The Daysimeter, a circadian light meter, measured light/dark exposures in both groups for seven days. Circadian timing was significantly delayed for those students who wore orange glasses compared to the control group. Sleep durations were slightly, but not significantly, curtailed in the orange-glasses group. Performance scores on a brief, standardized psychomotor vigilance test and self-reports of well-being were not significantly different between the two groups.
https://pubmed.ncbi.nlm.nih.gov/23504437/
A field study was conducted with eighth-grade students to determine the impact of morning light on circadian timing, sleep duration and performance. Before and during school hours for a week in February 2009, half the students studied wore orange glasses that minimized short-wavelength light exposure needed for circadian system stimulation. A control group did not wear the orange glasses. The Daysimeter, a circadian light meter, measured light/dark exposures in both groups for seven days. Circadian timing was significantly delayed for those students who wore orange glasses compared to the control group. Sleep durations were slightly, but not significantly, curtailed in the orange-glasses group. Performance scores on a brief, standardized psychomotor vigilance test and self-reports of well-being were not significantly different between the two groups.
https://pubmed.ncbi.nlm.nih.gov/23504437/
The impact of light from computer monitors on melatonin levels in college students
Neuro Endocrinol Lett. 2011;32(2):158-63. Mariana G Figueiro, Brittany Wood, Barbara Plitnick, Mark S ReaPMID: 21552190
The effect of light from computer screens regarding the attenuation of melatonin was investigated. The concentration of melatonin after using a light visor was significantly reduced compared to sleep glasses...
The impact of light from computer monitors on melatonin levels in college students
The effect of light from computer screens regarding the attenuation of melatonin was investigated. The concentration of melatonin after using a light visor was significantly reduced compared to sleep glasses and the computer screen. Although not statistically significant, mean melatonin concentration after exposure to the computer screen was only slightly reduced compared to sleep glasses.
The impact of light from computer monitors on melatonin levels in college students
Neuro Endocrinol Lett. 2011;32(2):158-63.
PMID: 21552190
Abstract
Objectives: Self-luminous electronic devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Melatonin suppression resulting from exposure to light at night has been linked to increased risk for diseases. The impact of luminous cathode ray tube (CRT) computer monitors on melatonin suppression was investigated
Design: Twenty-one participants experienced three test conditions: 1) computer monitor only, 2) computer monitor viewed through goggles providing 40 lux of short-wavelength (blue; peak λ ≈ 470 nm) light at the cornea from light emitting diodes (LEDs), and 3) computer monitor viewed through orange-tinted safety glasses (optical radiation <525 nm ≈ 0). The blue-light goggles were used as a "true-positive" experimental condition to demonstrate protocol effectiveness; the same light treatment had been shown in a previous study to suppress nocturnal melatonin. The orange-tinted glasses served as a "dark" control condition because the short-wavelength radiation necessary for nocturnal melatonin suppression was eliminated. Saliva samples were collected from subjects at 23:00, before starting computer tasks, and again at midnight and 01:00 while performing computer tasks under all three experimental conditions.
Results: Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition.
Conclusions: Additional empirical data should be collected to test the effectiveness of different, brighter and larger screens on melatonin suppression.
https://pubmed.ncbi.nlm.nih.gov/21552190/
Objectives: Self-luminous electronic devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Melatonin suppression resulting from exposure to light at night has been linked to increased risk for diseases. The impact of luminous cathode ray tube (CRT) computer monitors on melatonin suppression was investigated
Design: Twenty-one participants experienced three test conditions: 1) computer monitor only, 2) computer monitor viewed through goggles providing 40 lux of short-wavelength (blue; peak λ ≈ 470 nm) light at the cornea from light emitting diodes (LEDs), and 3) computer monitor viewed through orange-tinted safety glasses (optical radiation <525 nm ≈ 0). The blue-light goggles were used as a "true-positive" experimental condition to demonstrate protocol effectiveness; the same light treatment had been shown in a previous study to suppress nocturnal melatonin. The orange-tinted glasses served as a "dark" control condition because the short-wavelength radiation necessary for nocturnal melatonin suppression was eliminated. Saliva samples were collected from subjects at 23:00, before starting computer tasks, and again at midnight and 01:00 while performing computer tasks under all three experimental conditions.
Results: Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition.
Conclusions: Additional empirical data should be collected to test the effectiveness of different, brighter and larger screens on melatonin suppression.
https://pubmed.ncbi.nlm.nih.gov/21552190/
Using blue-green light at night and blue-blockers during the day to improves adaptation to night work: a pilot study
Prog Neuropsychopharmacol Biol Psychiatry. 2010 Oct 1;34(7):1236-42. doi: 10.1016/j.pnpbp.2010.06.027. Epub 2010 Jul 3.Alexandre Sasseville, Marc HébertPMID: 20599459 / DOI: 10.1016/j.pnpbp.2010.06.027
We investigated the adjustment ability of shift workers who were exposed to blue-green light at night and who used sleep glasses during the day. After one week, the melatonin profiles...
Using blue-green light at night and blue-blockers during the day to improves adaptation to night work: a pilot study
We investigated the adjustment ability of shift workers who were exposed to blue-green light at night and who used sleep glasses during the day. After one week, the melatonin profiles of three participants changed by at least two hours. Improvements were observed in sleep parameters and subjective alertness from the third night, as performance increased on the quarter night from 5.14% to 1.36% of errors (p=0.04). The trial showed that strategic exposure to blue-green light at night and/or the use of sleep glasses during the day appeared to improve sleep, alertness and performance.
Using blue-green light at night and blue-blockers during the day to improves adaptation to night work: a pilot study
Prog Neuropsychopharmacol Biol Psychiatry. 2010 Oct 1;34(7):1236-42. doi: 10.1016/j.pnpbp.2010.06.027. Epub 2010 Jul 3.
PMID: 20599459 / DOI: 10.1016/j.pnpbp.2010.06.027
Abstract:
Background: Bright light at night paired with darkness during the day seem to facilitate adaptation to night work. Considering the biological clock sensitive to short wavelengths, we investigated the possibility of adaptation in shift workers exposed to blue-green light at night, combined with using blue-blockers during the day.
Methods: Four sawmill shift workers were evaluated during two weeks of night shifts (control and experimental) and one week of day shifts. Throughout the experimental week, ambient light (approximately 130 lx) was supplemented with blue-green light (200 lx) from 00:00 h to: 05:00 h on Monday and Tuesday, 06:00 h on Wednesday and 07:00 h on Thursday. Blue-blockers had to be worn outside from the end of the night shift until 16:00 h. For circadian assessment, salivary melatonin profiles were obtained between 00:00 h and 08:00 h, before and after 4 experimental night shifts. Sleep was continuously monitored with actigraphy and subjective vigilance was measured at the beginning, the middle and the end of each night and day shifts. The error percentage in wood board classification was used as an index of performance.
Results: Through experimental week, melatonin profiles of 3 participants have shifted by at least 2 hours. Improvements were observed in sleep parameters and subjective vigilance from the third night (Wednesday) as performance increased on the fourth night (Thursday) from 5.14% to 1.36% of errors (p=0.04).
Conclusions: Strategic exposure to short wavelengths at night, and/or daytime use of blue-blocker glasses, seemed to improve sleep, vigilance and performance.
https://pubmed.ncbi.nlm.nih.gov/20599459/
Background: Bright light at night paired with darkness during the day seem to facilitate adaptation to night work. Considering the biological clock sensitive to short wavelengths, we investigated the possibility of adaptation in shift workers exposed to blue-green light at night, combined with using blue-blockers during the day.
Methods: Four sawmill shift workers were evaluated during two weeks of night shifts (control and experimental) and one week of day shifts. Throughout the experimental week, ambient light (approximately 130 lx) was supplemented with blue-green light (200 lx) from 00:00 h to: 05:00 h on Monday and Tuesday, 06:00 h on Wednesday and 07:00 h on Thursday. Blue-blockers had to be worn outside from the end of the night shift until 16:00 h. For circadian assessment, salivary melatonin profiles were obtained between 00:00 h and 08:00 h, before and after 4 experimental night shifts. Sleep was continuously monitored with actigraphy and subjective vigilance was measured at the beginning, the middle and the end of each night and day shifts. The error percentage in wood board classification was used as an index of performance.
Results: Through experimental week, melatonin profiles of 3 participants have shifted by at least 2 hours. Improvements were observed in sleep parameters and subjective vigilance from the third night (Wednesday) as performance increased on the fourth night (Thursday) from 5.14% to 1.36% of errors (p=0.04).
Conclusions: Strategic exposure to short wavelengths at night, and/or daytime use of blue-blocker glasses, seemed to improve sleep, vigilance and performance.
https://pubmed.ncbi.nlm.nih.gov/20599459/
Amber lenses to block blue light and improve sleep: a randomized trial
Chronobiol Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719.Kimberly Burkhart, James R PhelpsPMID: 20030543 / DOI: 10.3109/07420520903523719
All light is not the same: blue wavelengths are the most potent part of the visible electromagnetic spectrum for circadian regulation. Therefore, blocking blue light could create a form of...
Amber lenses to block blue light and improve sleep: a randomized trial
All light is not the same: blue wavelengths are the most potent part of the visible electromagnetic spectrum for circadian regulation. Therefore, blocking blue light could create a form of physiological darkness. Since the timing and amount of light and darkness both affect sleep, wearing sleep glasses at night to block blue light can affect sleep quality. At the end of the study, the sleep glasses group experienced a significant (p < 0.001) improvement in sleep quality compared to the control group and a positive effect (p = 0.005). Mood was also significantly improved compared to the controls.
Amber lenses to block blue light and improve sleep: a randomized trial
Chronobiol Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719.
PMID: 20030543 / DOI: 10.3109/07420520903523719
Abstract
All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. Therefore, blocking blue light could create a form of physiologic darkness. Because the timing and quantity of light and darkness both affect sleep, evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; therefore, mood might be affected by blue light blockade. In this study, 20 adult volunteers were randomized to wear either blue-blocking (amber) or yellow-tinted (blocking ultraviolet only) safety glasses for 3 h prior to sleep. Participants completed sleep diaries during a one-week baseline assessment and two weeks' use of glasses. Outcome measures were subjective: change in overall sleep quality and positive/negative affect. Results demonstrated that sleep quality at study outset was poorer in the amber lens than the control group. Two- by three-way ANOVA revealed significant (p < .001) interaction between quality of sleep over the three weeks and experimental condition. At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls. A replication with more detailed data on the subjects' circadian baseline and objective outcome measures is warranted.
https://pubmed.ncbi.nlm.nih.gov/20030543/
All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. Therefore, blocking blue light could create a form of physiologic darkness. Because the timing and quantity of light and darkness both affect sleep, evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; therefore, mood might be affected by blue light blockade. In this study, 20 adult volunteers were randomized to wear either blue-blocking (amber) or yellow-tinted (blocking ultraviolet only) safety glasses for 3 h prior to sleep. Participants completed sleep diaries during a one-week baseline assessment and two weeks' use of glasses. Outcome measures were subjective: change in overall sleep quality and positive/negative affect. Results demonstrated that sleep quality at study outset was poorer in the amber lens than the control group. Two- by three-way ANOVA revealed significant (p < .001) interaction between quality of sleep over the three weeks and experimental condition. At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls. A replication with more detailed data on the subjects' circadian baseline and objective outcome measures is warranted.
https://pubmed.ncbi.nlm.nih.gov/20030543/
Plasma melatonin rhythms in young and older humans during sleep, sleep deprivation, and wake
Sleep. 2007 Nov;30(11):1437-43. doi: 10.1093/sleep/30.11.1437.Jamie M Zeitzer, Jeanne F Duffy, Steven W Lockley, Derk-Jan Dijk, Charles A CzeislerPMID: 18041478 / PMCID: PMC2082092 / DOI: 10.1093/sleep/30.11.1437
The trial aimed to clarify the effects of sleep and sleep deprivation on plasma melatonin concentrations in humans, and whether these effects are age-dependent. Investigation of plasma melatonin concentrations and...
Plasma melatonin rhythms in young and older humans during sleep, sleep deprivation, and wake
The trial aimed to clarify the effects of sleep and sleep deprivation on plasma melatonin concentrations in humans, and whether these effects are age-dependent. Investigation of plasma melatonin concentrations and core body temperature. Study 1. There was a small but significant effect of sleep deprivation of up to 50 hours on melatonin concentrations (increase of 9.81 +/- 3.73%, P <0.05, compared with normal timed melatonin). There was also an effect of the circadian phase angle with the preceding sleep episode, such that if the onset of melatonin production occurred <8 h after the wake time, the amplitude was significantly lower (22.4% +/- 4.79%, P <0.001). Study 2. Comparing melatonin concentrations during sleep with the same hours during constant wakefulness, in young men, the melatonin amplitude was 6.7% +/- 2.1% higher (P <0.001) during the sleep episode. In older men, the melatonin amplitude was 37.0% +/- 12.5% lower ( P <0.05) during the sleep episode, and in older women the melatonin amplitude was non-significantly 10.9% +/- 8.38% lower ( P = 0.13) during the sleep episode. Conclusion: Both sleep and sleep deprivation probably affect melatonin amplitude, and the effect of sleep on melatonin appears to be age-dependent.
Plasma melatonin rhythms in young and older humans during sleep, sleep deprivation, and wake
Sleep. 2007 Nov;30(11):1437-43. doi: 10.1093/sleep/30.11.1437.
PMID: 18041478 / PMCID: PMC2082092 / DOI: 10.1093/sleep/30.11.1437
Abstract
Study objectives: To determine the effects of sleep and sleep deprivation on plasma melatonin concentrations in humans and whether these effects are age-dependent.
Design: At least 2 weeks of regular at-home, sleep/wake schedule followed by 3 baseline days in the laboratory and at least one constant routine (sleep deprivation).
Setting: General Clinical Research Center (GCRC), Brigham and Women's Hospital, Boston, MA.
Participants: In Study 1, one group (<10 lux when awake) of 19 young men (18-30 y) plus a second group (<2 lux when awake) of 15 young men (20-28 y) and 10 young women (19-27 y); in Study 2, 90 young men (18-30 y), 18 older women (65-81 y), and 11 older men (64-75 y). All participants were in good health, as determined by medical and psychological screening.
Interventions: One to three constant routines with interspersed inversion of the sleep/wake cycle in those with multiple constant routines.
Measurements and results: Examination of plasma melatonin concentrations and core body temperature. Study 1. There was a small, but significant effect of sleep deprivation of up to 50 hours on melatonin concentrations (increase of 9.81 +/- 3.73%, P <0.05, compared to normally timed melatonin). There was also an effect of circadian phase angle with the prior sleep episode, such that if melatonin onset occurred <8 hours after wake time, the amplitude was significantly lower (22.4% +/- 4.79%, P <0.001). Study 2. In comparing melatonin concentrations during sleep to the same hours during constant wakefulness, in young men, melatonin amplitude was 6.7% +/- 2.1% higher(P <0.001) during the sleep episode. In older men, melatonin amplitude was 37.0% +/- 12.5% lower (P <0.05) during the sleep episode and in older women, melatonin amplitude was non-significantly 10.9% +/- 8.38% lower (P = 0.13) during the sleep episode.
Conclusions: Both sleep and sleep deprivation likely influence melatonin amplitude, and the effect of sleep on melatonin appears to be age dependent.
https://pubmed.ncbi.nlm.nih.gov/18041478/
Study objectives: To determine the effects of sleep and sleep deprivation on plasma melatonin concentrations in humans and whether these effects are age-dependent.
Design: At least 2 weeks of regular at-home, sleep/wake schedule followed by 3 baseline days in the laboratory and at least one constant routine (sleep deprivation).
Setting: General Clinical Research Center (GCRC), Brigham and Women's Hospital, Boston, MA.
Participants: In Study 1, one group (<10 lux when awake) of 19 young men (18-30 y) plus a second group (<2 lux when awake) of 15 young men (20-28 y) and 10 young women (19-27 y); in Study 2, 90 young men (18-30 y), 18 older women (65-81 y), and 11 older men (64-75 y). All participants were in good health, as determined by medical and psychological screening.
Interventions: One to three constant routines with interspersed inversion of the sleep/wake cycle in those with multiple constant routines.
Measurements and results: Examination of plasma melatonin concentrations and core body temperature. Study 1. There was a small, but significant effect of sleep deprivation of up to 50 hours on melatonin concentrations (increase of 9.81 +/- 3.73%, P <0.05, compared to normally timed melatonin). There was also an effect of circadian phase angle with the prior sleep episode, such that if melatonin onset occurred <8 hours after wake time, the amplitude was significantly lower (22.4% +/- 4.79%, P <0.001). Study 2. In comparing melatonin concentrations during sleep to the same hours during constant wakefulness, in young men, melatonin amplitude was 6.7% +/- 2.1% higher(P <0.001) during the sleep episode. In older men, melatonin amplitude was 37.0% +/- 12.5% lower (P <0.05) during the sleep episode and in older women, melatonin amplitude was non-significantly 10.9% +/- 8.38% lower (P = 0.13) during the sleep episode.
Conclusions: Both sleep and sleep deprivation likely influence melatonin amplitude, and the effect of sleep on melatonin appears to be age dependent.
https://pubmed.ncbi.nlm.nih.gov/18041478/
Thermoregulatory effects of melatonin in relation to sleepiness
Chronobiol Int. 2006;23(1-2):475-84. doi: 10.1080/07420520500545854.Kurt Kräuchi, Christian Cajochen, Mona Pache, Josef Flammer, Anna Wirz-JusticePMID: 16687320 / DOI: 10.1080/07420520500545854
In this study, we review our own studies conducted over the last decade that demonstrate a crucial role for melatonin as a mediator between the thermoregulatory and vigilance systems in...
Thermoregulatory effects of melatonin in relation to sleepiness
In this study, we review our own studies conducted over the last decade that demonstrate a crucial role for melatonin as a mediator between the thermoregulatory and vigilance systems in humans. Taken together, melatonin is involved in the fine-tuning of vascular tone in selective vascular filters, as circulating melatonin levels rise and fall during the night. In addition to melatonin's role as "nature's anaesthetic," it may also serve as nature's nocturnal vascular modulator.
Thermoregulatory effects of melatonin in relation to sleepiness
Chronobiol Int. 2006;23(1-2):475-84. doi: 10.1080/07420520500545854.
PMID: 16687320 / DOI: 10.1080/07420520500545854
Abstract
Thermoregulatory processes have long been implicated in the initiation of human sleep. In this paper, we review our own studies conducted over the last decade showing a crucial role for melatonin as a mediator between the thermoregulatory and arousal system in humans. Distal heat loss, via increased skin temperature, seems to be intimately coupled with increased sleepiness and sleep induction. Exogenous melatonin administration during the day when melatonin is essentially absent mimics the endogenous thermophysiological processes occurring in the evening and induces sleepiness. Using a cold thermic challenge test, it was shown that melatonin-induced sleepiness occurs in parallel with reduction in the thermoregulatory set-point (threshold); thus, melatonin may act as a circadian modulator of the thermoregulatory set-point. In addition, an orthostatic challenge can partially block the melatonin-induced effects, suggesting an important role of the sympathetic nervous system as a link between the thermoregulatory and arousal systems. A topographical analysis of finger skin temperature with infrared thermometry revealed that the most distal parts of the fingers, i.e., fingertips, represent the important skin regions for heat loss regulation, most probably via opening the arteriovenous anastomoses, and this is clearly potentiated by melatonin. Taken together, melatonin is involved in the fine-tuning of vascular tone in selective vascular beds, as circulating melatonin levels rise and fall throughout the night. Besides the role of melatonin as "nature's soporific", it can also serve as nature's nocturnal vascular modulator.
https://pubmed.ncbi.nlm.nih.gov/16687320/
Thermoregulatory processes have long been implicated in the initiation of human sleep. In this paper, we review our own studies conducted over the last decade showing a crucial role for melatonin as a mediator between the thermoregulatory and arousal system in humans. Distal heat loss, via increased skin temperature, seems to be intimately coupled with increased sleepiness and sleep induction. Exogenous melatonin administration during the day when melatonin is essentially absent mimics the endogenous thermophysiological processes occurring in the evening and induces sleepiness. Using a cold thermic challenge test, it was shown that melatonin-induced sleepiness occurs in parallel with reduction in the thermoregulatory set-point (threshold); thus, melatonin may act as a circadian modulator of the thermoregulatory set-point. In addition, an orthostatic challenge can partially block the melatonin-induced effects, suggesting an important role of the sympathetic nervous system as a link between the thermoregulatory and arousal systems. A topographical analysis of finger skin temperature with infrared thermometry revealed that the most distal parts of the fingers, i.e., fingertips, represent the important skin regions for heat loss regulation, most probably via opening the arteriovenous anastomoses, and this is clearly potentiated by melatonin. Taken together, melatonin is involved in the fine-tuning of vascular tone in selective vascular beds, as circulating melatonin levels rise and fall throughout the night. Besides the role of melatonin as "nature's soporific", it can also serve as nature's nocturnal vascular modulator.
https://pubmed.ncbi.nlm.nih.gov/16687320/