Shift-Work Related Sleep DisturbanceNCT03203538
Light Intervention for Adaptation to Night Work
A study testing LED-light, 1000 lux, LED-light, 100 lux and LED-light, 7000 K in people with Shift-Work Related Sleep Disturbance and Sleep Deprivation, run by University of Bergen at 1 site in Norway.
Trial summary
The project will contribute with new knowledge concerning how aspects of the physical work environment (lighting conditions) can be arranged to facilitate the workers' adaptation to night work. This is important given the reported adverse consequences of shift work for performance, safety, and health. Read more about this study
- Who is it for?
- Ages 19 to 30 yearsHealthy volunteers can take part
- Conditions the study is for
- Shift-Work Related Sleep Disturbance, Sleep Deprivation, Sleep
- What is being tested?
- LED-light, 1000 lux, LED-light, 100 lux and LED-light, 7000 K
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 97 participants
- Where
- 1 siteNorway
- Study dates
- 25 Aug 2017to 27 Mar 2019
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 30 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Participants are physical and mentally healthy (assessed with BMI and 'General Health Questionnaire-12')
- Participants accept to comply with the protocol (refrain from alcohol, tobacco and coffee, and retain regular bed- and wake-times the week before the simulated night shifts)
Who cannot join
- Neurological, psychiatric or sleep related disorders ('Bergen Insomnia Scale', 'global sleep assessement questionnaire')
- Extreme 'morningness-eveningness' type ('Horne Östberg morningness eveningness questionnaire')
- Use of medication
- Worked night shifts the last 3 months
- Travelled through more than two time zones the last 3 months
Trial locations and contacts
1 site in 1 country.
Norway1 site
The faculty of psychology, University of Bergen
Bergen, Hordaland, 5020
About this study
Official title: Effects of Bright Light Intervention for Adaptation to Night Work: Shift Work Simulation Experiments
The project will contribute with new knowledge concerning how aspects of the physical work environment (lighting conditions) can be arranged to facilitate the workers' adaptation to night work. This is important given the reported adverse consequences of shift work for performance, safety, and health. The project involves a series of three experimental, laboratory based shift work simulation studies. The aim is to investigate how different lighting conditions (intensities and colour temperature), administered through light emitting diode (LED) based bright light integrated standard room lighting, affects adaptation to three consecutive simulated night shifts and re adaptation to a day oriented schedule on measures of alertness, cognitive performance, sleep and circadian rhythm. The proposed project examines the effects of interventions that can be applied in naturalistic settings and will be based on new laboratory infrastructure available at the laboratories situated in the Faculty of Psychology, University of Bergen.
Read the detailed description
Bright light has been suggested as a countermeasure to the negative impact of night work in terms of safety, performance and subsequent sleep. The effect depends on the timing of light (e.g, phase-response curve), duration of light exposure and the intensity of light, as well as the wavelengths that are emitted. Exposure to bright light (more intense than typical room lightning), at evening and night, has been effective in delaying the circadian rhythm to sufficiently adapt to night work both in simulated night work, and in field studies of workers. Blue light has significantly stronger phase shifting effects than other wavelengths of the visible spectrum. The effect of light on the circadian system is mediated by retinal photoresponsive cell population (intrinsically photoresponsive retinal ganglion cells; ipRGC) that contains the photopigment melanopsin, highly sensitive to blue light. These cells signal directly to the suprachiasmatic nuclei (SCN) of the hypothalamus, the circadian pacemaker. Bright light has also been reported to improve alertness and performance during night shifts.
To the best of the investigators knowledge, no shift work simulation study has made the full advance of LED-technology in terms of using light administered via standard room lighting on adaptation to night work. Today, new LED-technology represents an excellent opportunity to study this as roof mounted LED-sources integrated as standard indoor lightening can be programmed to provide a wide range of light intensities and colour temperatures. LED-sources have the advantage over standard light therapy that subjects can be exposed to the therapy via standard room lightening (not confined to a special therapy lamp) thereby allowing the workers to conduct work tasks as normal during light exposure.
Against this backdrop this project aims to investigate how different lighting conditions, administered through LED-based bright light integrated standard room lighting, affects adaptation to three consecutive simulated night shifts and re adaptation to a day oriented schedule on measures of alertness, cognitive performance, sleep and circadian rhythm. In addition, measures of mood, appetite, heart rate variability (HRV), pain sensitivity, moral reasoning, and inflammatory markers will be examined. The researchers also aim to investigate the effects of two extreme monochromatic light conditions (blue vs. red) based on integrated standard room lighting on the adaptation to one simulated night shift.
Study participants will work simulated night shifts (11:00 pm to 07:00 am) in a light laboratory where light parameters (intensity and colour temperature) can be manipulated via roof mounted LED-sources integrated as standard indoor lightening. Participants will be recruited among students at the University of Bergen, and a screening will be done to ensure healthy participants fit for the study. The included participants will take part in experiments with two bouts of three consecutive simulated night shifts (6 nights in total).
HRV will be measured throughout the night shift, and five times, approx. every 1.5 hour (11:30 pm, 01:00 am, 02:30 am, 04:00 am, 05:30 am), the subjects will be tested on a test battery of cognitive tests and will rate their subjective sleepiness. Sleep will be assessed by sleep diary and actigraphy 3 days prior to, during, and 3 days following the shifts. One day before the night shift and the day after the night shift period the circadian rhythm will be measured by saliva samples for estimation of dim light melatonin onset. Prior to-, during- and after the night shifts, participants will undergo a pain sensitivity test. Blood spot samples will be collected at the beginning and the end of each night shift for analysis of inflammatory markers (e.g. interleukins).
- Being tested
- LED-light, 1000 lux, LED-light, 100 lux, LED-light, 7000 K, LED-light, 2500 K, Blue LED-light
- Keywords
- night work, shift work, light, bright light, sleep, cognitive performance, circadian rhythm
- Medical subject headings
- Sleep Deprivation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LED-light, 1000 luxDevice
Full-spectrum light, 1000 lux, 4000 K. Represent a light intensity within acceptable range (light that is not too glary); 4000 K is among the most commonly used indoor light colour temperatures.
LED-light, 100 luxDevice
Full-spectrum light, 100 lux, 4000 K. Represent a light intensity within acceptable range (light that provides sufficient eye sight); 4000 K is among the most commonly used indoor light colour temperatures.
LED-light, 7000 KDevice
Full-spectrum light, 7000 K, 200 lux. Represent the upper border of common colour indoor light temperature, 200 lux is a common indoor light intensity.
LED-light, 2500 KDevice
Full-spectrum light, 2500 K, 200 lux. Represent the lower border of common colour indoor light temperature, 200 lux is a common indoor light intensity.
Blue LED-lightDevice
Blue light with peak wavelength 455 nm. Known to delay the circadian rhythm, suppress melatonin, and increase alertness.
Red LED-lightDevice
Red light with peak wavelength 615 nm. Known not to affect the circadian rhythm, melatonin, and alertness.
| Study group | Role | What they receive |
|---|---|---|
| Light intensity, 1000 lux (4000 K) | Experimental | Participants will work three consecutive simulated night shifts under full-spectrum LED-light, 1000 lux (4000 Kelvin) administered through standard room lighting. Receives: Device: LED-light, 1000 lux |
| Light intensity, 100 lux (4000 K) | Active comparator | Participants will work three consecutive simulated night shifts under full-spectrum LED-light, 100 lux (4000 Kelvin) administered through standard room lighting. Receives: Device: LED-light, 100 lux |
| Colour temperature, 7000 Kelvin | Experimental | Participants will work three consecutive simulated night shifts under full-spectrum LED-light, 7000 K (200 lux) administered through standard room lighting. Receives: Device: LED-light, 7000 K |
| Colour temperature, 2500 Kelvin | Active comparator | Participants will work three consecutive simulated night shifts under full-spectrum LED-light, 2500 K (200 lux) administered through standard room lighting. Receives: Device: LED-light, 2500 K |
| Blue light, 455 nm | Experimental | Participants work one night shift with blue LED-light (peak wavelength 455 nm) administered through standard room lighting. Receives: Device: Blue LED-light |
| Red light, 615 nm | Active comparator | Participants work one night shift with red LED-light (peak wavelength 615 nm) administered through standard room lighting. Receives: Device: Red LED-light |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cognitive performance
Cognitive performance will be measured using the Psychomotor Vigilance Test (PVT). The PVT measures sustained attention, and is considered the 'gold standard' for assessing the effects of sleep deprivation on cognition. The task will be performed approx. every 1.5h throughout the nightshifts.
Measured: 3 nights
Circadian phase
Circadian phase will be measured through assessement of 'Dim Light Melatonin Onset' (DLMO). Saliva samples will be collected every hour in the evening (from 7 pm) to one hour past regular bedtime, one day before the first night shift and the day after the night shift period. Saliva will be analyzed for melatonin, giving an estimate on DLMO.
Measured: 5 days-nights
Sleep
Sleep will be measured objectively using actigraphy
Measured: 9 days-nights
Secondary outcomes (25)
Subjective sleepiness
Karolinska Sleepiness Scale (KSS) will be used to assess subjective sleepiness throughout the night shifts. KSS is a likert scale ranging from 1-9, where subjects rate their sleepiness. '1' indicates 'extremely alert', '9' indicates 'very sleepy/fighting sleep'.
Measured: 3 nights
Self-reported sleep
A sleep diary will be used.
Measured: 9 days-nights
Heart rate variability
'Heart Rate Variability' will be assessed by using Polar heart rate monitor V800 that will continuously monitor 'HRV' through the night.
Measured: 3 nights
Interleukin
Blood spot samples will be analyzed for interleukins (IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13)
Measured: 3 nights
Granulocyte macrophage colony-stimulating factor (GM-CSF)
Blood-spot samples will be analyzed for GM-CSF.
Measured: 3 nights
Interferon gamma (IFN-gamma)
Blood-spot samples will be analyzed for IFN-gamma.
Measured: 3 nights
Tumor necrosis factor alpha (TNF-a)
Blood-spot samples will be analyzed for TNF-a
Measured: 3 nights
Positive and negative affect
'Positive and Negative Affect Schedule', will be administered to assess mood.
Measured: 3 nights
Pain sensitivity
By using a handheld pressure algometer, Wagner FPIX Force One, the pressure pain threshold will be measured. The test site will be the trapezius muscle, and the pressure will be increased in steps of 5 N/sec until the participant indicates pain.
Measured: 3 nights
Headache and eyestrain
A 'Headache and Eyestrain Scale' will be used to get subjective measures on how participants perceive the lighting conditions.
Measured: 3 nights
Appetite/ food cravings
Appetite/ food cravings for different food types will be assessed using a visual analogue scale to record response to questions like: "How much would you like to eat xxx right now?"
A 'Dot-probe test' provides measure of attentional bias towards various food types (pictures)
Measured: 3 nights
Working memory
A 'Working Memory Scanning Task' measure ability to encode and maintain information in working memory
Measured: 3 nights
Decision/ response execution
A 'Two-Choice Numerosity Discrimination Task' measure decision criterion and response execution
Measured: 3 nights
Decision/ response inhibition
A 'Reversal Learning Decision Task' measure ability to adjust choices/ response inhibition
Measured: 3 nights
Cognitive control
A 'Task Switching-Performance Test' measure cognitive control
Measured: 3 nights
Planning
The 'Tower of Hanoi Test' measure planning and sequencing abilities
Measured: 3 nights
Moral reasoning
the 'Defining Issues Test' measure moral reasoning.
Measured: 3 nights
Cognitive throughput
A 'Digit Symbol Substitution Test' will be used as a measure of cognitive throughput
Measured: 3 nights
Fine motor skills
The 'grooved pegboard test' assess fine motor skills through the night shifts
Measured: 3 nights
Recognition of emotions
An 'emotional hexagon test', were participants rate standardized pictures of faces expressing different emotions, measure the ability to discriminate between emotional expressions.
Measured: 3 nights
Pupil size
Pupil size will be measured, using a tobii eyetracker, three times during night shifts. This can provide an objective measure of sleepiness.
Measured: 3 nights
Core body temperature
To get a secondary measure of circadian phase, core body temperature will be measured using ingestible temperature capsules.
Measured: 1-2 nights
Leadership evaluation
The 'Multifactor Leadership Questionnaire' will be used to assess participants leadership preferences. The questionnaire will be administered during daytime and during night shifts.
Measured: 2 nights, 1 day
Experiences of perceptual anomalies
The Cardiff Anomalous Perceptions Scale (CAPS) questionnaire will be administered after the night shifts to assess experiences of hallucinations and perceptual anomalies during night shifts. The questionnaire consists of 32 items/questions regarding perceptual anomalies, e.g. "Do you ever notice that sounds are much louder than they normally would be?", that are answered with 'yes' or 'no'. Adding up the number of 'yes' answers gives the CAPS Total Score ranging from 0 (low) to 32 (high). For each item endorsed, participants rate the item for distress, intrusiveness and frequency, giving three subscales. The rating for subscales goes from 1 (low) to 5 (high). Nonendorsed items are considered to have a score of 0 on subscales. For each subscale the possible range goes from 0 (low) to 160 (high).
Measured: 3 nights
Objective sleepiness, sleep and sleep stages
A subgroup of participants (12-16 in each experiment) will be subject to electroencephalography (EEG) during night shifts, and polysomnography (PSG) after night shifts. EEG will provide a measure of electrical activity in the brain during wakefulness, and can provide an objective measure of sleepiness. PSG will be conducted in the sleep period after night shifts, and allow for the scoring of sleep stages. PSG is considered the gold standard for measuring sleep.
Measured: 3 nights and sleep periods
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jun 2017
- Study start25 Aug 2017
- Primary completion27 Mar 2019
- Study completion27 Mar 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Shift-Work Related Sleep DisturbanceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Three related night shift studies have been planned. Each study investigates how different lighting conditions, administered through LED-based bright light integrated standard room lighting, affects adaptation to simulated night shifts and re adaptation to a day oriented schedule. In each study, 28 participants (84 in total) will be exposed to the interventions (light conditions) in a randomized, blinded, controlled, crossover study. The simulated night shifts will last from 11pm to 7am. The specific light conditions will last from 11pm to 5am (study 1: 1000 lux vs. 100 lux; study 2: 7000 K vs. 2500 K; study 3: 455 nm vs. 615 nm) where after (from 5am to 7am) all participants will be exposed to the same light conditions (200 lux, 4000 K). After completion of one bout of night work (three consecutive shifts for study 1 and 2; one night shift for study 3) there will be a washout period of four weeks before the participants cross over.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 97 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Bergen
- Sponsor type
- University, hospital or other
- Collaborators
- Glamox
- Responsible party
- Sponsor
- Investigators
- Erlend Sunde, Principal investigator, University of Bergen, department of psychosocial science
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03203538
- Sponsor's protocol ID
- 270755
- Status last verified
- Feb 2018
- First submitted
- 3 May 2017
- Last updated
- 16 May 2019
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: After the project has ended the data will be anonymized and no direct recognizable information will be stored.
Publications
Sunde E, Harris A, Olsen OK, Pallesen S. Moral decision-making at night and the impact of night work with blue-enriched white light or warm white light: a counterbalanced crossover study. Ann Med. 2024 Dec;56(1):2331054. doi: 10.1080/07853890.2024.2331054. Epub 2024 Apr 18.
PubMed 38635448Sunde E, Mrdalj J, Pedersen TT, Bjorvatn B, Gronli J, Harris A, Waage S, Pallesen S. Bright light exposure during simulated night work improves cognitive flexibility. Chronobiol Int. 2022 Jul;39(7):948-963. doi: 10.1080/07420528.2022.2050922. Epub 2022 Mar 28.
PubMed 35343353Sunde E, Pedersen T, Mrdalj J, Thun E, Gronli J, Harris A, Bjorvatn B, Waage S, Skene DJ, Pallesen S. Alerting and Circadian Effects of Short-Wavelength vs. Long-Wavelength Narrow-Bandwidth Light during a Simulated Night Shift. Clocks Sleep. 2020 Nov 25;2(4):502-522. doi: 10.3390/clockssleep2040037.
PubMed 33255613Sunde E, Pedersen T, Mrdalj J, Thun E, Gronli J, Harris A, Bjorvatn B, Waage S, Skene DJ, Pallesen S. Blue-Enriched White Light Improves Performance but Not Subjective Alertness and Circadian Adaptation During Three Consecutive Simulated Night Shifts. Front Psychol. 2020 Aug 18;11:2172. doi: 10.3389/fpsyg.2020.02172. eCollection 2020.
PubMed 33013558Sunde E, Mrdalj J, Pedersen T, Thun E, Bjorvatn B, Gronli J, Harris A, Waage S, Pallesen S. Role of nocturnal light intensity on adaptation to three consecutive night shifts: a counterbalanced crossover study. Occup Environ Med. 2020 Apr;77(4):249-255. doi: 10.1136/oemed-2019-106049. Epub 2020 Feb 4.
PubMed 32019847
Study at a glance
From the registry record, last updated by the sponsor on 16 May 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Bright Light Intervention for Adaptation to Night Work: Shift Work Simulation Experiments
- ClinicalTrials.gov ID
- NCT03203538
- Acronym / sponsor ID
- 270755
- Keywords
- night work, shift work, light, bright light, sleep, cognitive performance, circadian rhythm
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 97 participants (actual)
- Lead sponsor
- University of BergenUniversity, hospital or other
- Collaborators
- Glamox
- Study start
- 25 Aug 2017 (actual)
- Primary completion
- 27 Mar 2019 (actual)
- Study completion
- 27 Mar 2019 (actual)
- First posted
- 29 Jun 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The project will contribute with new knowledge concerning how aspects of the physical work environment (lighting conditions) can be arranged to facilitate the workers' adaptation to night work. This is important given the reported adverse consequences of shift work for performance, safety, and health. The project involves a series of three experimental, laboratory based shift work simulation studies. The aim is to investigate how different lighting conditions (intensities and colour temperature), administered through light emitting diode (LED) based bright light integrated standard room lighting, affects adaptation to three consecutive simulated night shifts and re adaptation to a day oriented schedule on measures of alertness, cognitive performance, sleep and circadian rhythm. The proposed project examines the effects of interventions that can be applied in naturalistic settings and will be based on new laboratory infrastructure available at the laboratories situated in the Faculty of Psychology, University of Bergen.
Detailed description
Bright light has been suggested as a countermeasure to the negative impact of night work in terms of safety, performance and subsequent sleep. The effect depends on the timing of light (e.g, phase-response curve), duration of light exposure and the intensity of light, as well as the wavelengths that are emitted. Exposure to bright light (more intense than typical room lightning), at evening and night, has been effective in delaying the circadian rhythm to sufficiently adapt to night work both in simulated night work, and in field studies of workers. Blue light has significantly stronger phase shifting effects than other wavelengths of the visible spectrum. The effect of light on the circadian system is mediated by retinal photoresponsive cell population (intrinsically photoresponsive retinal ganglion cells; ipRGC) that contains the photopigment melanopsin, highly sensitive to blue light. These cells signal directly to the suprachiasmatic nuclei (SCN) of the hypothalamus, the circadian pacemaker. Bright light has also been reported to improve alertness and performance during night shifts.
To the best of the investigators knowledge, no shift work simulation study has made the full advance of LED-technology in terms of using light administered via standard room lighting on adaptation to night work. Today, new LED-technology represents an excellent opportunity to study this as roof mounted LED-sources integrated as standard indoor lightening can be programmed to provide a wide range of light intensities and colour temperatures. LED-sources have the advantage over standard light therapy that subjects can be exposed to the therapy via standard room lightening (not confined to a special therapy lamp) thereby allowing the workers to conduct work tasks as normal during light exposure.
Against this backdrop this project aims to investigate how different lighting conditions, administered through LED-based bright light integrated standard room lighting, affects adaptation to three consecutive simulated night shifts and re adaptation to a day oriented schedule on measures of alertness, cognitive performance, sleep and circadian rhythm. In addition, measures of mood, appetite, heart rate variability (HRV), pain sensitivity, moral reasoning, and inflammatory markers will be examined. The researchers also aim to investigate the effects of two extreme monochromatic light conditions (blue vs. red) based on integrated standard room lighting on the adaptation to one simulated night shift.
Study participants will work simulated night shifts (11:00 pm to 07:00 am) in a light laboratory where light parameters (intensity and colour temperature) can be manipulated via roof mounted LED-sources integrated as standard indoor lightening. Participants will be recruited among students at the University of Bergen, and a screening will be done to ensure healthy participants fit for the study. The included participants will take part in experiments with two bouts of three consecutive simulated night shifts (6 nights in total).
HRV will be measured throughout the night shift, and five times, approx. every 1.5 hour (11:30 pm, 01:00 am, 02:30 am, 04:00 am, 05:30 am), the subjects will be tested on a test battery of cognitive tests and will rate their subjective sleepiness. Sleep will be assessed by sleep diary and actigraphy 3 days prior to, during, and 3 days following the shifts. One day before the night shift and the day after the night shift period the circadian rhythm will be measured by saliva samples for estimation of dim light melatonin onset. Prior to-, during- and after the night shifts, participants will undergo a pain sensitivity test. Blood spot samples will be collected at the beginning and the end of each night shift for analysis of inflammatory markers (e.g. interleukins).
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 6
- Model description
- Three related night shift studies have been planned. Each study investigates how different lighting conditions, administered through LED-based bright light integrated standard room lighting, affects adaptation to simulated night shifts and re adaptation to a day oriented schedule. In each study, 28 participants (84 in total) will be exposed to the interventions (light conditions) in a randomized, blinded, controlled, crossover study. The simulated night shifts will last from 11pm to 7am. The specific light conditions will last from 11pm to 5am (study 1: 1000 lux vs. 100 lux; study 2: 7000 K vs. 2500 K; study 3: 455 nm vs. 615 nm) where after (from 5am to 7am) all participants will be exposed to the same light conditions (200 lux, 4000 K). After completion of one bout of night work (three consecutive shifts for study 1 and 2; one night shift for study 3) there will be a washout period of four weeks before the participants cross over.
| Arm | Type | Receives |
|---|---|---|
| Light intensity, 1000 lux (4000 K) | Experimental | Device: LED-light, 1000 luxParticipants will work three consecutive simulated night shifts under full-spectrum LED-light, 1000 lux (4000 Kelvin) administered through standard room lighting. |
| Light intensity, 100 lux (4000 K) | Active comparator | Device: LED-light, 100 luxParticipants will work three consecutive simulated night shifts under full-spectrum LED-light, 100 lux (4000 Kelvin) administered through standard room lighting. |
| Colour temperature, 7000 Kelvin | Experimental | Device: LED-light, 7000 KParticipants will work three consecutive simulated night shifts under full-spectrum LED-light, 7000 K (200 lux) administered through standard room lighting. |
| Colour temperature, 2500 Kelvin | Active comparator | Device: LED-light, 2500 KParticipants will work three consecutive simulated night shifts under full-spectrum LED-light, 2500 K (200 lux) administered through standard room lighting. |
| Blue light, 455 nm | Experimental | Device: Blue LED-lightParticipants work one night shift with blue LED-light (peak wavelength 455 nm) administered through standard room lighting. |
| Red light, 615 nm | Active comparator | Device: Red LED-lightParticipants work one night shift with red LED-light (peak wavelength 615 nm) administered through standard room lighting. |
Who may qualify
- Ages
- 19 to 30 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Participants are physical and mentally healthy (assessed with BMI and 'General Health Questionnaire-12')
- Participants accept to comply with the protocol (refrain from alcohol, tobacco and coffee, and retain regular bed- and wake-times the week before the simulated night shifts)
Key exclusion criteria (5 listed)
- Neurological, psychiatric or sleep related disorders ('Bergen Insomnia Scale', 'global sleep assessement questionnaire')
- Extreme 'morningness-eveningness' type ('Horne Östberg morningness eveningness questionnaire')
- Use of medication
- Worked night shifts the last 3 months
- Travelled through more than two time zones the last 3 months
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LED-light, 1000 luxFull-spectrum light, 1000 lux, 4000 K. Represent a light intensity within acceptable range (light that is not too glary); 4000 K is among the most commonly used indoor light colour temperatures. | Device | Light intensity, 1000 lux (4000 K) |
| LED-light, 100 luxFull-spectrum light, 100 lux, 4000 K. Represent a light intensity within acceptable range (light that provides sufficient eye sight); 4000 K is among the most commonly used indoor light colour temperatures. | Device | Light intensity, 100 lux (4000 K) |
| LED-light, 7000 KFull-spectrum light, 7000 K, 200 lux. Represent the upper border of common colour indoor light temperature, 200 lux is a common indoor light intensity. | Device | Colour temperature, 7000 Kelvin |
| LED-light, 2500 KFull-spectrum light, 2500 K, 200 lux. Represent the lower border of common colour indoor light temperature, 200 lux is a common indoor light intensity. | Device | Colour temperature, 2500 Kelvin |
| Blue LED-lightBlue light with peak wavelength 455 nm. Known to delay the circadian rhythm, suppress melatonin, and increase alertness. | Device | Blue light, 455 nm |
| Red LED-lightRed light with peak wavelength 615 nm. Known not to affect the circadian rhythm, melatonin, and alertness. | Device | Red light, 615 nm |
Primary outcome
Cognitive performance
Time frame: 3 nights
Cognitive performance will be measured using the Psychomotor Vigilance Test (PVT). The PVT measures sustained attention, and is considered the 'gold standard' for assessing the effects of sleep deprivation on cognition. The task will be performed approx. every 1.5h throughout the nightshifts.
Circadian phase
Time frame: 5 days-nights
Circadian phase will be measured through assessement of 'Dim Light Melatonin Onset' (DLMO). Saliva samples will be collected every hour in the evening (from 7 pm) to one hour past regular bedtime, one day before the first night shift and the day after the night shift period. Saliva will be analyzed for melatonin, giving an estimate on DLMO.
Sleep
Time frame: 9 days-nights
Sleep will be measured objectively using actigraphy
25 secondary outcomes
Subjective sleepiness
Time frame: 3 nights
Self-reported sleep
Time frame: 9 days-nights
Heart rate variability
Time frame: 3 nights
Interleukin
Time frame: 3 nights
Granulocyte macrophage colony-stimulating factor (GM-CSF)
Time frame: 3 nights
Interferon gamma (IFN-gamma)
Time frame: 3 nights
Tumor necrosis factor alpha (TNF-a)
Time frame: 3 nights
Positive and negative affect
Time frame: 3 nights
Pain sensitivity
Time frame: 3 nights
Headache and eyestrain
Time frame: 3 nights
Appetite/ food cravings
Time frame: 3 nights
Working memory
Time frame: 3 nights
Decision/ response execution
Time frame: 3 nights
Decision/ response inhibition
Time frame: 3 nights
Cognitive control
Time frame: 3 nights
Planning
Time frame: 3 nights
Moral reasoning
Time frame: 3 nights
Cognitive throughput
Time frame: 3 nights
Fine motor skills
Time frame: 3 nights
Recognition of emotions
Time frame: 3 nights
Pupil size
Time frame: 3 nights
Core body temperature
Time frame: 1-2 nights
Leadership evaluation
Time frame: 2 nights, 1 day
Experiences of perceptual anomalies
Time frame: 3 nights
Objective sleepiness, sleep and sleep stages
Time frame: 3 nights and sleep periods
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 May 2019.
- Derived from this study: PubMed 38635448Sunde E, Harris A, Olsen OK, Pallesen S. Moral decision-making at night and the impact of night work with blue-enriched white light or warm white light: a counterbalanced crossover study. Ann Med. 2024 Dec;56(1):2331054. doi: 10.1080/07853890.2024.2331054. Epub 2024 Apr 18.
- Derived from this study: PubMed 35343353Sunde E, Mrdalj J, Pedersen TT, Bjorvatn B, Gronli J, Harris A, Waage S, Pallesen S. Bright light exposure during simulated night work improves cognitive flexibility. Chronobiol Int. 2022 Jul;39(7):948-963. doi: 10.1080/07420528.2022.2050922. Epub 2022 Mar 28.
- Derived from this study: PubMed 33255613Sunde E, Pedersen T, Mrdalj J, Thun E, Gronli J, Harris A, Bjorvatn B, Waage S, Skene DJ, Pallesen S. Alerting and Circadian Effects of Short-Wavelength vs. Long-Wavelength Narrow-Bandwidth Light during a Simulated Night Shift. Clocks Sleep. 2020 Nov 25;2(4):502-522. doi: 10.3390/clockssleep2040037.
- Derived from this study: PubMed 33013558Sunde E, Pedersen T, Mrdalj J, Thun E, Gronli J, Harris A, Bjorvatn B, Waage S, Skene DJ, Pallesen S. Blue-Enriched White Light Improves Performance but Not Subjective Alertness and Circadian Adaptation During Three Consecutive Simulated Night Shifts. Front Psychol. 2020 Aug 18;11:2172. doi: 10.3389/fpsyg.2020.02172. eCollection 2020.
- Derived from this study: PubMed 32019847Sunde E, Mrdalj J, Pedersen T, Thun E, Bjorvatn B, Gronli J, Harris A, Waage S, Pallesen S. Role of nocturnal light intensity on adaptation to three consecutive night shifts: a counterbalanced crossover study. Occup Environ Med. 2020 Apr;77(4):249-255. doi: 10.1136/oemed-2019-106049. Epub 2020 Feb 4.
- Individual participant dataSharing planned: No. After the project has ended the data will be anonymized and no direct recognizable information will be stored.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Erlend Sunde principal investigator
University of Bergen, department of psychosocial science
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing LED-light, 1000 lux, LED-light, 100 lux and LED-light, 7000 K in people with Shift-Work Related Sleep Disturbance and Sleep Deprivation, run by University of Bergen at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 May 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cognitive performance (time frame: 3 nights). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03203538, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 May 2019.