HealthyNCT00200863
Effects of Different Colors of Light on Human Physiology
A study testing Monochromatic visible light exposure in people with Healthy and Circadian Rhythm, run by Brigham and Women's Hospital at 1 site in United States.
Trial summary
This study will determine which color of light is most effective in stimulating a range of biological functions in humans including activation of sleep-wake regulatory system (alertness, performance, microsleeps, brain activity), activation of the nervous system (heart rate, temperature, blood pressure, breathing… Read more about this study
- Who is it for?
- Ages 18 to 30 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Circadian Rhythm
- What is being tested?
- Monochromatic visible light exposure
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 47 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2005to Feb 2007
- 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 18 to 30 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Free from any acute, chronic or debilitating medical, psychological, or ophthalmological conditions
- Drug-free (including caffeine, nicotine, and alcohol) for entire study duration
Who cannot join
- History of drug or alcohol dependency
- History of psychiatric illnesses or evidence of psychopathology according to standardized questionnaires, or in a structured clinical interview
- Night shift work during the past 3 years
- Transmeridian travel in the last 3 months
Trial locations and contacts
1 site in 1 country.
United States1 site
Division of Sleep Medicine, Brigham and Women's Hospital
Boston, Massachusetts, 02115
About this study
Official title: Mechanism Underlying the Effects of Blue Light in Humans
This study will determine which color of light is most effective in stimulating a range of biological functions in humans including activation of sleep-wake regulatory system (alertness, performance, microsleeps, brain activity), activation of the nervous system (heart rate, temperature, blood pressure, breathing rate), and shifting the timing of the internal 24-hour (circadian) pacemaker.
Read the detailed description
Light has long been proposed to have a stimulatory effect on a range of biological functions in humans including increased feelings of activation, such as improved alertness or ability to perform. The mechanisms underlying how light stimulates these neurobiological systems remain to be elucidated. We propose to investigate the effects of different colors of light on human physiology, and in particular, test the claims that specific colors of light preferentially stimulate neurobiological, physiological and hormonal systems. Using classical photobiological techniques, we will construct action spectra for the effects of different colors of light on a range of non-image forming responses in humans.
We will test the hypotheses that: 1) light-induced activation of the neurobiological sleep-wake regulatory system, as indicated by increased alertness, faster reaction time, suppression of EEG alpha activity, microsleeps and slow rolling eye movements, and suppression of pineal melatonin, is most sensitive to retinal exposure to short wavelength blue light (460 nm) compared to equal photons of other colors of visible light; 2) light-induced activation of autonomic and hypothalamic-pituitary-adrenal axis measures of arousal, as indicated by increased heart rate variability, core body temperature, blood pressure, respiration rate, plasma cortisol levels and urinary catecholamines, is most sensitive to exposure to short wavelength blue light (460 nm) compared to equal photons of other colors; 3) phase shifts of the human circadian pacemaker, as assessed by changes in temperature, melatonin and cortisol rhythms, are most sensitive to exposure to short wavelength blue light (460 nm) compared to equal photons of other colors. The resultant action spectra will help to identify the photoreceptor mechanism(s) by which light activates arousal and circadian resetting, these non-image-forming physiological responses and enable us to distinguish between major candidate photoreceptive mechanisms, including potential novel photoreceptor systems, that might mediate such responses.
- Conditions
- Healthy, Circadian Rhythm
- Being tested
- Monochromatic visible light exposure
- Keywords
- light, wavelength, action spectrum, circadian, melatonin, alertness, performance, arousal
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Monochromatic visible light exposureDevice
Monochromatic light in the visible range from 420-620 nm up to 60uW/cm2 for 6.5 hours
| Study group | Role | What they receive |
|---|---|---|
| 1 | Experimental | 420 nm light Receives: Device: Monochromatic visible light exposure |
| 2 | Experimental | 480 nm Receives: Device: Monochromatic visible light exposure |
| 3 | Experimental | 507 nm Receives: Device: Monochromatic visible light exposure |
| 4 | Experimental | 555 nm Receives: Device: Monochromatic visible light exposure |
| 5 | Experimental | 620 nm Receives: Device: Monochromatic visible light exposure |
| 6 | Experimental | 460 nm Receives: Device: Monochromatic visible light exposure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Subjective alertness prior to, during and after light exposure
Measured: 9.5 hours
Auditory psychomotor performance prior to, during and after light exposure
Measured: 9.5 hours
EEG power frequency prior to, during and after light exposure
Measured: 9.5 hours
Plasma melatonin and cortisol prior to, during and after light exposure
Measured: 60 hours
Heart rate, blood pressure, respiration rate and temperature prior to, during and after light exposure
Measured: 9.5 hours
Urinary catecholamines prior to, during and after light exposure
Measured: 32 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Sep 2005 (estimated)
- Study startApr 2005
- Primary completionFeb 2007
- Study completionFeb 2007
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 47 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- National Center for Complementary and Integrative Health (NCCIH)
- Responsible party
- Principal investigator, Steven W. Lockley, Brigham and Women's Hospital
- Investigators
- Steven W Lockley, Ph.D., Principal investigator, Brigham and Women's Hospital, Harvard Medical School
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00200863
- Sponsor's protocol ID
- R01AT002129-01
- Other IDs
- R01AT002129-01
- Status last verified
- Aug 2014
- First submitted
- 12 Sep 2005
- Last updated
- 12 Aug 2014
- Results posted
- No
- Data monitoring committee
- No
Publications
Gooley JJ, Chamberlain K, Smith KA, Khalsa SB, Rajaratnam SM, Van Reen E, Zeitzer JM, Czeisler CA, Lockley SW. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. J Clin Endocrinol Metab. 2011 Mar;96(3):E463-72. doi: 10.1210/jc.2010-2098. Epub 2010 Dec 30.
PubMed 21193540
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Mechanism Underlying the Effects of Blue Light in Humans
- ClinicalTrials.gov ID
- NCT00200863
- Acronym / sponsor ID
- R01AT002129-01
- Conditions
- Healthy, Circadian Rhythm
- Keywords
- light, wavelength, action spectrum, circadian, melatonin, alertness, performance, arousal
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 47 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Collaborators
- National Center for Complementary and Integrative Health (NCCIH)
- Study start
- Apr 2005
- Primary completion
- Feb 2007 (actual)
- Study completion
- Feb 2007 (actual)
- First posted
- 20 Sep 2005 (estimated)
- 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.
This study will determine which color of light is most effective in stimulating a range of biological functions in humans including activation of sleep-wake regulatory system (alertness, performance, microsleeps, brain activity), activation of the nervous system (heart rate, temperature, blood pressure, breathing rate), and shifting the timing of the internal 24-hour (circadian) pacemaker.
Detailed description
Light has long been proposed to have a stimulatory effect on a range of biological functions in humans including increased feelings of activation, such as improved alertness or ability to perform. The mechanisms underlying how light stimulates these neurobiological systems remain to be elucidated. We propose to investigate the effects of different colors of light on human physiology, and in particular, test the claims that specific colors of light preferentially stimulate neurobiological, physiological and hormonal systems. Using classical photobiological techniques, we will construct action spectra for the effects of different colors of light on a range of non-image forming responses in humans.
We will test the hypotheses that: 1) light-induced activation of the neurobiological sleep-wake regulatory system, as indicated by increased alertness, faster reaction time, suppression of EEG alpha activity, microsleeps and slow rolling eye movements, and suppression of pineal melatonin, is most sensitive to retinal exposure to short wavelength blue light (460 nm) compared to equal photons of other colors of visible light; 2) light-induced activation of autonomic and hypothalamic-pituitary-adrenal axis measures of arousal, as indicated by increased heart rate variability, core body temperature, blood pressure, respiration rate, plasma cortisol levels and urinary catecholamines, is most sensitive to exposure to short wavelength blue light (460 nm) compared to equal photons of other colors; 3) phase shifts of the human circadian pacemaker, as assessed by changes in temperature, melatonin and cortisol rhythms, are most sensitive to exposure to short wavelength blue light (460 nm) compared to equal photons of other colors. The resultant action spectra will help to identify the photoreceptor mechanism(s) by which light activates arousal and circadian resetting, these non-image-forming physiological responses and enable us to distinguish between major candidate photoreceptive mechanisms, including potential novel photoreceptor systems, that might mediate such responses.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 6
| Arm | Type | Receives |
|---|---|---|
| 1 | Experimental | Device: Monochromatic visible light exposure420 nm light |
| 2 | Experimental | Device: Monochromatic visible light exposure480 nm |
| 3 | Experimental | Device: Monochromatic visible light exposure507 nm |
| 4 | Experimental | Device: Monochromatic visible light exposure555 nm |
| 5 | Experimental | Device: Monochromatic visible light exposure620 nm |
| 6 | Experimental | Device: Monochromatic visible light exposure460 nm |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Free from any acute, chronic or debilitating medical, psychological, or ophthalmological conditions
- Drug-free (including caffeine, nicotine, and alcohol) for entire study duration
Key exclusion criteria (4 listed)
- History of drug or alcohol dependency
- History of psychiatric illnesses or evidence of psychopathology according to standardized questionnaires, or in a structured clinical interview
- Night shift work during the past 3 years
- Transmeridian travel in 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 |
|---|---|---|
| Monochromatic visible light exposureMonochromatic light in the visible range from 420-620 nm up to 60uW/cm2 for 6.5 hours | Device | 1, 2, 3, 4, 5, 6 |
Primary outcome
Subjective alertness prior to, during and after light exposure
Time frame: 9.5 hours
Auditory psychomotor performance prior to, during and after light exposure
Time frame: 9.5 hours
EEG power frequency prior to, during and after light exposure
Time frame: 9.5 hours
Plasma melatonin and cortisol prior to, during and after light exposure
Time frame: 60 hours
Heart rate, blood pressure, respiration rate and temperature prior to, during and after light exposure
Time frame: 9.5 hours
Urinary catecholamines prior to, during and after light exposure
Time frame: 32 hours
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 12 Aug 2014.
- Derived from this study: PubMed 21193540Gooley JJ, Chamberlain K, Smith KA, Khalsa SB, Rajaratnam SM, Van Reen E, Zeitzer JM, Czeisler CA, Lockley SW. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. J Clin Endocrinol Metab. 2011 Mar;96(3):E463-72. doi: 10.1210/jc.2010-2098. Epub 2010 Dec 30.
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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.
Steven W Lockley, Ph.D. principal investigator
Brigham and Women's Hospital, Harvard Medical School
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Monochromatic visible light exposure in people with Healthy and Circadian Rhythm, run by Brigham and Women's Hospital at 1 site in United States.
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 4 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 12 Aug 2014. 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 United States. 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?
Subjective alertness prior to, during and after light exposure (time frame: 9.5 hours). The study lists 6 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 NCT00200863, which also lists 1 linked publication.
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 12 Aug 2014; AzTrials last refreshed its copy on 7 Nov 2026.