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/
Søvnproblemer
Mangel på søvn er ofte en følge af det moderne menneskes hektiske liv, og det kan have mange uheldige fysiske såvel som psykiske bivirkninger. F.eks. bliver hormonbalancen, immunforsvaret og stofskiftet påvirket, ligesom det også går ud over koncentrationsevnen, hukommelsen, præstationsevnen, indlæringsevnen, humøret, og kroppen ældes hurtigere.
Beskrivelse
Søvnproblemer og søvn
Årsagen til søvnproblemer er blandt andet ubalancer i vores naturlige døgnrytme, da den naturlige produktion af melatonin hæmmes på grund af blåt lys, som kommer fra lysforurening (kunstig belysning, TV og PC).
Over et døgn kan kroppen højst opretholde en maksimal produktion af det naturlige søvnmiddel, melatonin, i ca. 10-12 timer i træk. Hos voksne med en velafbalanceret døgnrytme sker produktionen af melatonin, typisk i 9-10 timer i nattetimerne – og det er vel at mærke i mørke.
Søvnproblemer og søvnbriller
Mange forsøger at løse problemet med dyre og vanedannende sovepiller, men der findes et sundt alternativ, nemlig søvnbriller. En enkel løsning, som er helt fri for generende bivirkninger.
Mennesker, der af den ene eller anden grund har ubalance i deres melatoninproduktion, kan forbedre deres søvn bemærkelsesværdigt ved at bruge søvnbriller.
Resultatet er, at man lettere falder i søvn. Søvnen bliver sund og dyb, og man vågner udhvilet og frisk om morgenen, da melatoninproduktionen er faldende.
Søvnbriller er et sundt alternativ, der generelt virker efter blot 1-5 dages brug.
Hvis man f.eks. skal op næste morgen kl. 6:00 og have 8 timers søvn, skal man gå i seng kl. 22:00. I dette tilfælde skal man iføre sig søvnbrillerne f.eks. kl. 21:00. Hvis man falder i søvn før kl. 22:00, så kan man forsøge sig at bære brillerne i mindre tid. Hvis man derimod ikke er søvnig og falder let i søvn, når man går i seng kl. 22:00, så skal man udvide den tid man bærer søvnbrillerne. Man mindsker eller forøger den tid, man bærer søvnbrillerne med intervaller af 10 minutter.
Børn, unge og søvn
Alt for mange børn og unge går for sent i seng og får for lidt søvn. De er ikke udhvilede, når de bliver vækket tidligt om morgenen, når de skal i børnehave eller skole.
En tommelfingerregel er, at børn i alderen 5-9 skal sove 10-12 timer om natten. Børn i alderen 10-13 skal sove 9-11 timer om natten og teenagere skal sove 8-10 timer om natten.
Mange børnehave- og skolebørn er knap vågne i de første timer i børnehave og skole på grund af for få timers søvn om natten. Dette påvirker i høj grad deres velbefindende og evne til at lære.
Problemet kan undgås ved at fremrykke tidspunktet om aftenen, hvor produktionen af melatonin starter. Dette opnås ved, at barnet undgår at udsætte øjnene for blåt lys et par timer før den planlagte sengetid.
Den store synder i dag er smartphones, tablets, computere og til dels TV, som mange børn og unge bruger lige indtil de skal sove. De udsender alle blåt lys, og det kan få børn og unge til at forsinke deres behov for søvn og have svært ved at falde i søvn.
Børn, unge og søvnbriller
Den mest praktiske metode er at bruge søvnbriller, som blokerer for det blå lys i lysspektret.
I løbet af et par dage, når barnet eller den unge har undgået blåt lys om aftenen, vil cyklussen for produktionen af melatonin blive fremrykket, så den slutter i god tid før mødetid i børnehave eller skole.
Om vinteren kan fremgangen konsolideres ved, at barnet får lysterapi med blåt lys kort efter at være vågnet om morgenen. Lysterapi kan være i form af en lysterapilampe eller en wake-up lampe.
Forskning vedrørende søvnproblemer
Digital afhængighed og søvn
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
I 2020 anerkendte Verdenssundhedsorganisationen formelt afhængighed af digital teknologi som et verdensomspændende problem, hvor overdreven onlineaktivitet og internetbrug fører til manglende evne til at styre tid, energi og opmærksomhed i...
Digital afhængighed og søvn
I 2020 anerkendte Verdenssundhedsorganisationen formelt afhængighed af digital teknologi som et verdensomspændende problem, hvor overdreven onlineaktivitet og internetbrug fører til manglende evne til at styre tid, energi og opmærksomhed i dagtimerne og eller søvnløshed om natten. Når man ser på digitale skærme, som afgiver blåt lys over mange timer om dagen og natten, så kan det medføre adfærdssymptomer, som omfatter spiseforstyrrelser og tilbagetrækning fra udendørs og socialt liv.
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
Lysforurening
Rev Prat. 2022 Feb;72(2):141-146.Jean-Louis Dufier, Yvan TouitouPMID: 35289519
Kunstigt lys kan være skadeligt i forhold til toksiciteten af det blå lys (380-500 nm) af det synlige spektrum (380-700 nm), der specifikt anvendes i lysdioder (LED'er). Udsættelse for lys...
Lysforurening
Kunstigt lys kan være skadeligt i forhold til toksiciteten af det blå lys (380-500 nm) af det synlige spektrum (380-700 nm), der specifikt anvendes i lysdioder (LED'er). Udsættelse for lys om natten forstyrrer stofskiftet alvorligt. Udsættelse for kunstigt lys om natten forstyrrer det indre ur. Lys hæmmer udskillelsen af melatonin og er i stand til at fremskynde eller forsinke det indre ur. Skifteholds- og natarbejdere er ligesom teenagere udsat for lys om natten. Forekomsten af brystkræft er højere hos sygeplejersker der er udsat for lys om natten. Teenageres eksponering for skærme er også tvivlsom. De kroniske desynkroniseringer af både skifteholdsarbejdere og unge bør betragtes som et stort folkesundhedsproblem.
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/
Brug af søvnbriller om aftenen for søvn og mod depression: en systemstisk gennemgang
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
Man har undersøgt søvnbriller mod søvnløshed, døgnrytmeforskydelse, skifteholdsarbejde, jetlag og ikke-patologiske søvnforbedringer. Man har også undersøgt søvnbriller som behandling mod bipolar lidelse, depression og fødselsdepression. Ud af 24 publicerede forsøg...
Brug af søvnbriller om aftenen for søvn og mod depression: en systemstisk gennemgang
Man har undersøgt søvnbriller mod søvnløshed, døgnrytmeforskydelse, skifteholdsarbejde, jetlag og ikke-patologiske søvnforbedringer. Man har også undersøgt søvnbriller som behandling mod bipolar lidelse, depression og fødselsdepression. Ud af 24 publicerede forsøg med fokus på søvnen var der betydelig bevisførelse for, at brug af søvnbriller er en succesfuld behandling ved søvnproblemer, jetlag og skifteholdsarbejde.
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/
Søvnbrillers effekt på subjektiv og objektiv søvn hos raske voksne: et tilfældigt kontrolforsøg
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
Denne undersøgelse tester hypoteses om, at søvnbriller forbedrer subjektiv og objektiv søvn hos en gruppe raske voksne. Undersøgelsen viste, at søvnbriller ikke forbedrede søvnens varighed eller søvnkvalitet.
Søvnbrillers effekt på subjektiv og objektiv søvn hos raske voksne: et tilfældigt kontrolforsøg
Denne undersøgelse tester hypoteses om, at søvnbriller forbedrer subjektiv og objektiv søvn hos en gruppe raske voksne. Undersøgelsen viste, at søvnbriller ikke forbedrede søvnens varighed eller søvnkvalitet.
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/
Evaluering af to strategier til at lindre effekten på døgnrytmen fra smartphone-skærme
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
Undersøgelsen skulle sammenligne den stråling fra smartphones, der rammer øjnene, når man bruger app med natfunktion eller computerbriller. App’s med natfunktion i smartphones reducerede MSV'er med op til 93 %. Den højeste...
Evaluering af to strategier til at lindre effekten på døgnrytmen fra smartphone-skærme
Undersøgelsen skulle sammenligne den stråling fra smartphones, der rammer øjnene, når man bruger app med natfunktion eller computerbriller. App’s med natfunktion i smartphones reducerede MSV'er med op til 93 %. Den højeste indstilling gav den mindste dæmpning af melatonin produktionen. Computerbriller reducerede dæmpningen af melatonin med 33 % og er mere effektive end tonede briller. Smartphones kan forringe reguleringen af døgnrytme om natten. Aktiveringen af app’en med nattfunktion var mere effektiv end computerbriller til at reducere mængden af blåt lys (op til 2,25 gange).
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/
Blåt lys indstiller det indre ur og deraf døgnrytmen hos mennesker
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
Det blå lys, er det stærkeste synkroniseringsmiddel for det døgnrytmen, der holder de fleste biologiske og psykologiske rytmer internt synkroniseret. Eksponering for blåt lys i løbet af dagen er vigtig...
Blåt lys indstiller det indre ur og deraf døgnrytmen hos mennesker
Det blå lys, er det stærkeste synkroniseringsmiddel for det døgnrytmen, der holder de fleste biologiske og psykologiske rytmer internt synkroniseret. Eksponering for blåt lys i løbet af dagen er vigtig for at undertrykke udskilning af melatonin (signalstof), der produceres af pinealkirtlen og spiller en afgørende rolle for døgnrytmen. Mens eksponeringen for blåt lys er vigtig for velbefindende, årvågenhed og kognitive ydeevne i løbet af dagtimerne, kan kronisk eksponering for blåt lys umiddelbart før sengetid have alvorlige konsekvenser for søvnkvaliteten, døgnrytmen og varigheden af cyklus.
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/
Okulært og systemisk melatonin og påvirkningen af lyseksponering
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 er et signalstof, der er kendt for at modulere en bred vifte af døgnrytmefunktioner, herunder søvn. Syntesen og frigivelsen af melatonin fra pinealkirtlen er stærkt påvirket af lysstimulering af...
Okulært og systemisk melatonin og påvirkningen af lyseksponering
Melatonin er et signalstof, der er kendt for at modulere en bred vifte af døgnrytmefunktioner, herunder søvn. Syntesen og frigivelsen af melatonin fra pinealkirtlen er stærkt påvirket af lysstimulering af nethinden. Dette medfører melatoninundertrykkelse, hvilket fører til overvejelser om, hvordan søvnbriller, grå stær og lysterapi kan påvirke søvn og humør hos patienter. Derudover diskuteres interaktionerne mellem melatonin, søvn og udvikling af brydningsfejl.
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/
Begrænset eksponering for blåt lys om aftenen for bedring af søvnen hos restituerende atleter – En pilopundersøgelse
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
Forsøget skulle undersøge om blokering af det blå lys om aftenen kan fremme søvnen og potentielt andre søvnparametre blandt restituerende atleter. Blokering af kortbølget lys om aftenen ved hjælp af ravfarvede...
Begrænset eksponering for blåt lys om aftenen for bedring af søvnen hos restituerende atleter – En pilopundersøgelse
Forsøget skulle undersøge om blokering af det blå lys om aftenen kan fremme søvnen og potentielt andre søvnparametre blandt restituerende atleter. Blokering af kortbølget lys om aftenen ved hjælp af ravfarvede briller er et omkostningseffektivt og lovende middel til at forbedre subjektive søvnestimater blandt rekreative atleter i deres sædvanlige hjemmemiljø.
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/
Blokering af blåt lys om natten for søvnløshed: Et tilfældigt kontrolleret forsøg
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
Brugen af elektroniske enheder med lysdisplay før sengetid kan medføre eller forværre søvnproblemer ved at undertrykke melatonin. Vi skulle afgøre, om det at bære søvnbriller før sengetid forbedrer søvnen hos...
Blokering af blåt lys om natten for søvnløshed: Et tilfældigt kontrolleret forsøg
Brugen af elektroniske enheder med lysdisplay før sengetid kan medføre eller forværre søvnproblemer ved at undertrykke melatonin. Vi skulle afgøre, om det at bære søvnbriller før sengetid forbedrer søvnen hos personer med søvnløshed. Brug af ravfarvede kontra klare linser i 2 timer før sengetid i 1 uge forbedrede søvnen hos personer med søvnløshedssymptomer. Disse resultater har sundhedsrelevans i betragtning af den brede brug af lysemitterende enheder før sengetid og forekomsten af søvnløshed. Søvnbriller repræsenterer en sikker, overkommelig og let implementeret terapeutisk intervention for søvnløshedssymptomer.
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/
Dæmpning af korte bølgelængder ændrer søvn og ipRGC-pupilrespons
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
Forsøget skulle vise, om melatoninniveau og søvnkvalitet kan ændres ved at reducere signal om nattetid til ipRGC'erne, ved hjælp af søvnbriller. Forsøget viste, at søvnbriller ved nattetide øgede subjektivt målt...
Dæmpning af korte bølgelængder ændrer søvn og ipRGC-pupilrespons
Forsøget skulle vise, om melatoninniveau og søvnkvalitet kan ændres ved at reducere signal om nattetid til ipRGC'erne, ved hjælp af søvnbriller. Forsøget viste, at søvnbriller ved nattetide øgede subjektivt målt søvnkvalitet og objektivt målte melatoninniveauer og søvnvarighed. Dette var formentlig som følge af nedsat nattestimulering af ipRGC'er. Ændringer i det ipRGC-drevne pupilrespons tyder på en ændring af døgnrytmen. Resultaterne tyder på, at en minimering af blåt lys efter solnedgang kan hjælpe med at regulere søvnmønstre.
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.
https://pubmed.ncbi.nlm.nih.gov/28656675/
Effekten ved brug af smartphones med og uden blåt lys om natten hos raske voksne: En tilfældig, dobbeltblinded, cross-over, placebokontrolleret sammenligning
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
Blåt lys fra bl.a. smartphones er den mest potente bølgelængde for søvn og humør. Blandt forsøgets 22 deltagere, var brug af smartphones forbundet med signifikant nedsat søvnighed og øget forvirringstilstand....
Effekten ved brug af smartphones med og uden blåt lys om natten hos raske voksne: En tilfældig, dobbeltblinded, cross-over, placebokontrolleret sammenligning
Blåt lys fra bl.a. smartphones er den mest potente bølgelængde for søvn og humør. Blandt forsøgets 22 deltagere, var brug af smartphones forbundet med signifikant nedsat søvnighed og øget forvirringstilstand. Brugere af smartphones oplevede også længere tid til at opnå start af melatoninproduktion i hjernen og de oplevede stigninger i kropstemperatur, serummelatoninniveauer og cortisolniveauer. Brug af blåt lys LED-smartphones om natten kan have en negativ indflydelse på søvn- og forvirringstilstand, mens det måske ikke er nok til at føre til væsentlige ændringer i serummelatonin- og cortisolniveauer.
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/
Søvnbriller: Optisk og klinisk ydeevne
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
Forsøget skal vurdere søvnbrillers optiske ydeevne og effekt, samt undersøge om en reduktion af blåt lys påvirker synlig ydeevne og søvnkvalitet. Konklusionen viser at søvnbriller delvis kan filtrere højenergi lys...
Søvnbriller: Optisk og klinisk ydeevne
Forsøget skal vurdere søvnbrillers optiske ydeevne og effekt, samt undersøge om en reduktion af blåt lys påvirker synlig ydeevne og søvnkvalitet. Konklusionen viser at søvnbriller delvis kan filtrere højenergi lys med kort bølgelængder uden at forringe den visuelle ydeevne og søvnkvaliteten. Søvnbriller kan fungere som et supplement til at beskytte nethinden mod blåt lys.
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/
Forstyrrelse af teenageres døgnrytme: Den onde cirkel af mediebrug, eksponering for lys om natten, søvntab og risikoadfærd
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
Det er med sundhedsrisiko at teenagere i større grad bruger tid online relateret til overdreven brug af elektroniske medier. Ungdomssøvnen bliver uregelmæssig, forkortet og forsinket i forhold til senere indsættelse...
Forstyrrelse af teenageres døgnrytme: Den onde cirkel af mediebrug, eksponering for lys om natten, søvntab og risikoadfærd
Det er med sundhedsrisiko at teenagere i større grad bruger tid online relateret til overdreven brug af elektroniske medier. Ungdomssøvnen bliver uregelmæssig, forkortet og forsinket i forhold til senere indsættelse af søvnen og tidlig vækning på grund af tidlige skolestarttider på hverdage. Dette resulterer i desynkronisering af døgnrytmen og søvntab. Endvidere er det blevet til stor bekymring, at de unge mennesker udsættes for eksponering af de mange elektroniske enheder før sengetid, fordi LED'er i enhederne udsender meget blåt lys og derfor har en større indflydelse på det biologiske ur.
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/
Søvnbriller kan ved brug om aftenen fremrykke døgnrytmen hos patienter med forsinket søvnfaseforstyrrelse: Et åbent forsøg
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
Vi undersøgte effekten af søvnbriller hos personer med forsinket søvnfaseforstyrrelse (DSPD). Patienterne der brugte søvnbriller, viste en fremrykning på 78 minutter i DLMO-værdi, selvom ændringen ikke var statistisk signifikant. Ikke...
Søvnbriller kan ved brug om aftenen fremrykke døgnrytmen hos patienter med forsinket søvnfaseforstyrrelse: Et åbent forsøg
Vi undersøgte effekten af søvnbriller hos personer med forsinket søvnfaseforstyrrelse (DSPD). Patienterne der brugte søvnbriller, viste en fremrykning på 78 minutter i DLMO-værdi, selvom ændringen ikke var statistisk signifikant. Ikke desto mindre blev søvnstarttiden målt med actigraph fremskreden med 132 minutter efter behandlingen. Disse data tyder på, at det at bære søvnbriller kan være en effektiv og sikker behandling af patienter med 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/
Større, lysere, blå’er-bedre? Nuværende enheder der afgiver lys -ugunstige søvnegenskaber og forebyggende strategier
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
Vi undersøgte omfanget af spredning af blåt lys ved hjælp af en tablet (iPad Air), e-læser (Kindle Paperwhite 1. generation) og smartphone (iPhone 5s), som alle afgiver blåt lys. Den første...
Større, lysere, blå’er-bedre? Nuværende enheder der afgiver lys -ugunstige søvnegenskaber og forebyggende strategier
Vi undersøgte omfanget af spredning af blåt lys ved hjælp af en tablet (iPad Air), e-læser (Kindle Paperwhite 1. generation) og smartphone (iPhone 5s), som alle afgiver blåt lys. Den første strategi var et par søvnbriller. Den anden strategi var en app, som var designet til at dæmpe mængden af blåt lys om aftenen. Både søvnbrillerne og app’en reducerede lysspredningen af blåt lys markant. Da denne type lys sandsynligvis vil forårsage mest forstyrrelse af søvnen, da det effektivt dæmper melatoninniveauet og øger årvågenhed, skal der være erkendelse af, at blåt lys ikke er godt.
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/
Søvnbriller mod lys fra skærme om aftenen hos mandlige teenagere
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
Vi undersøgte, om brugen af søvnbriller om aftenen, mens man sidder foran en computerskærm (LED), kan fremme søvnen på det subjektive, kognitive og fysiologiske niveau. Sammenlignet med klare linser dæmpede søvnbriller...
Søvnbriller mod lys fra skærme om aftenen hos mandlige teenagere
Vi undersøgte, om brugen af søvnbriller om aftenen, mens man sidder foran en computerskærm (LED), kan fremme søvnen på det subjektive, kognitive og fysiologiske niveau. Sammenlignet med klare linser dæmpede søvnbriller signifikant LED-induceret melatoninundertrykkelse om aftenen og nedsatte årvågen opmærksomhed og subjektiv årvågenhed før sengetid. Konklusion: Søvnbriller kan være nyttige hos unge mod lyseksponering fra LED-skærme og derfor potentielt hæmme de negative effekter, moderne belysning pålægger døgnfysiologien om aftenen.
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/
Effekten af kronotyper, søvnplan og lys/mørke ereksponeringer på døgnrytme-fasen
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
Under forsøget med et fremrykket lyseksponeringsmønster modtog deltagerne blåt lys om morgenen og søvnbriller om aftenen. I det forsinkende lyseksponeringsmønster modtog deltagerne søvnbriller om morgenen og kortbølgelængdelys om aftenen. De nuværende resultater...
Effekten af kronotyper, søvnplan og lys/mørke ereksponeringer på døgnrytme-fasen
Under forsøget med et fremrykket lyseksponeringsmønster modtog deltagerne blåt lys om morgenen og søvnbriller om aftenen. I det forsinkende lyseksponeringsmønster modtog deltagerne søvnbriller om morgenen og kortbølgelængdelys om aftenen. De nuværende resultater viser, at ændringer af døgnrytme-fasen er i overensstemmelse med dem, der er forudsagt af tidligere offentliggjorte faseresponskurver (PRC'er) for både tidlige og sene kronotyper.
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/
Styring af lys-mørke eksponeringsmønstre i stedet for søvnplaner over døgnrytmefase
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
Formålet med forsøget var at undersøge forskydning af døgnrytmen baseret på to forskellige lys-mørke eksponeringsmønstre. Efter syv dage på det 90-minutters avancerede søvnskema steg døgnfasen 132±19 minutter for fremskudsgruppen (blåt...
Styring af lys-mørke eksponeringsmønstre i stedet for søvnplaner over døgnrytmefase
Formålet med forsøget var at undersøge forskydning af døgnrytmen baseret på to forskellige lys-mørke eksponeringsmønstre. Efter syv dage på det 90-minutters avancerede søvnskema steg døgnfasen 132±19 minutter for fremskudsgruppen (blåt lys) og forsinket 59±7,5 minutter for forsinkelsesgruppen (søvnbriller). Konklusioner: Styring af et lys-mørke eksponeringsmønster rykker døgnrytmefasen i den forventede retning uanset det faste avancerede søvnskema.
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/
Lysniveau og eksponeringsvarighed bestemmer virkningen af lyset fra tablets på dæmpningen af melatoninniveau
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
Udsættelse for lys fra skærme kan være forbundet med øget risiko for søvnforstyrrelser, da disse enheder udsender blåt lys, der dæmper produktionen af melatonin. Til forsøget deltog forsøgspersoner der anvendte tablets...
Lysniveau og eksponeringsvarighed bestemmer virkningen af lyset fra tablets på dæmpningen af melatoninniveau
Udsættelse for lys fra skærme kan være forbundet med øget risiko for søvnforstyrrelser, da disse enheder udsender blåt lys, der dæmper produktionen af melatonin. Til forsøget deltog forsøgspersoner der anvendte tablets med hvidt lys, forsøgspersoner der anvendte tablets med blåt lys med placebobriller og forsøgspersoner der anvendte tablets med søvnbriller. Dæmpningen af melatoninproduktionen var størst ved brug af tablets med blåt lys.
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/
Måling af lys fordelt over døgnet og dets indvirkning på unge
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
Halvdelen af de studerende bar søvnbriller, der minimerer kortbølget lyseksponering, der er nødvendig for stimulering af døgnrytmen. En kontrolgruppe havde ikke søvnbriller på. Timingen af døgnrytmen var signifikant forsinket for...
Måling af lys fordelt over døgnet og dets indvirkning på unge
Halvdelen af de studerende bar søvnbriller, der minimerer kortbølget lyseksponering, der er nødvendig for stimulering af døgnrytmen. En kontrolgruppe havde ikke søvnbriller på. Timingen af døgnrytmen var signifikant forsinket for de elever, der bar søvnbriller sammenlignet med kontrolgruppen. Søvnvarigheden var lidt, men ikke signifikant, begrænset i gruppen med søvnbriller. Præstationsscore på en kort, standardiseret psykomotorisk årvågenhedstest og selvrapportering af velvære var ikke signifikant forskellige mellem de to grupper.
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/
Effekten af lys fra computerskærme på melatoninniveauer hos universitetsstuderende
Neuro Endocrinol Lett. 2011;32(2):158-63. Mariana G Figueiro, Brittany Wood, Barbara Plitnick, Mark S ReaPMID: 21552190
Lysets effekt fra computerskærme vedr. dæmpning af melatonin blev undersøgt. Koncentrationen af melatonin efter brug af lysvisir blev signifikant reduceret sammenlignet med søvnbriller og computerskærmen. Selvom det ikke var statistisk...
Effekten af lys fra computerskærme på melatoninniveauer hos universitetsstuderende
Lysets effekt fra computerskærme vedr. dæmpning af melatonin blev undersøgt. Koncentrationen af melatonin efter brug af lysvisir blev signifikant reduceret sammenlignet med søvnbriller og computerskærmen. Selvom det ikke var statistisk signifikant, blev den gennemsnitlige melatoninkoncentration efter eksponering for computerskærmen kun reduceret en smule i forhold til søvnbriller.
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/
Brug af blågrønt lys om natten og søvnbriller om dagen for at forbedre omstilling til natarbejde: en pilotundersøgelse
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
Vi undersøgte omstillingsevnen hos skifteholdsarbejdere, der var udsat for blågrønt lys om natten kombineret med brug af søvnbriller i dagtimerne. Efter en uge blev melatonin-profilerne for 3 deltagere ændret med...
Brug af blågrønt lys om natten og søvnbriller om dagen for at forbedre omstilling til natarbejde: en pilotundersøgelse
Vi undersøgte omstillingsevnen hos skifteholdsarbejdere, der var udsat for blågrønt lys om natten kombineret med brug af søvnbriller i dagtimerne. Efter en uge blev melatonin-profilerne for 3 deltagere ændret med mindst 2 timer. Forsøget viste at strategisk eksponering for blågrønt lys om natten og/eller brug af søvnbriller i dagtimerne syntes at forbedre søvn, årvågenhed og ydeevne.
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/
Søvnbriller til blokering af blåt lys og forbedring af søvnen: et randomiseret forsøg
Chronobiol Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719.Kimberly Burkhart, James R PhelpsPMID: 20030543 / DOI: 10.3109/07420520903523719
Alt lys er ikke ens: blå bølgelængder er den mest potente del af det synlige elektromagnetiske spektrum til regulering af døgnrytmen. Da timingen og mængden af lys og mørke begge...
Søvnbriller til blokering af blåt lys og forbedring af søvnen: et randomiseret forsøg
Alt lys er ikke ens: blå bølgelængder er den mest potente del af det synlige elektromagnetiske spektrum til regulering af døgnrytmen. Da timingen og mængden af lys og mørke begge påvirker søvnen, kan brug af søvnbriller om aftenen til at blokere blåt lys påvirke søvnkvaliteten. Ved afslutningen af undersøgelsen oplevede gruppen med søvnbriller en signifikant (p < 0,001) forbedring i søvnkvalitet i forhold til kontrolgruppen og positiv påvirkning (p = 0,005). Humøret forbedredes også betydeligt i forhold til kontrolgruppen.
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 rytmer hos unge og ældre mennesker under søvn, søvnmangel og i vågen tilstand
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
Forsøget skulle klarlægge virkningerne af søvn og søvnmangel på plasmamelatoninkoncentrationer hos mennesker, og om disse virkninger er aldersafhængige. Konklusion: Både søvn og søvnmangel påvirker sandsynligvis melatonin-amplituden, og effekten af søvn...
Plasma melatonin rytmer hos unge og ældre mennesker under søvn, søvnmangel og i vågen tilstand
Forsøget skulle klarlægge virkningerne af søvn og søvnmangel på plasmamelatoninkoncentrationer hos mennesker, og om disse virkninger er aldersafhængige. Konklusion: Både søvn og søvnmangel påvirker sandsynligvis melatonin-amplituden, og effekten af søvn på melatonin ser ud til at være aldersafhængig.
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/
Termoregulerende effekt af melatonin i forhold til søvnighed
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
I denne undersøgelse gennemgår vi vores egne undersøgelser udført i løbet af det sidste årti, der viser en afgørende rolle for melatonin som en mediator mellem det termoregulerende -og årvågenhedssystem...
Termoregulerende effekt af melatonin i forhold til søvnighed
I denne undersøgelse gennemgår vi vores egne undersøgelser udført i løbet af det sidste årti, der viser en afgørende rolle for melatonin som en mediator mellem det termoregulerende -og årvågenhedssystem hos mennesker. Tilsammen er melatonin involveret i finjusteringen af vaskulær tonus i selektive vaskulære filter, da cirkulerende melatoninniveauer stiger og falder i løbet af natten. Udover melatonins rolle som "naturens bedøvelsesmiddel", kan det også tjene som naturens natlige vaskulære 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/