Exposure to Man-made Visible LightNCT02919137
Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach (Substudy 7 of 7)
A study testing Visible light exposure in people with Exposure to Man-made Visible Light, run by University of Bern at 1 site in Switzerland.
Trial summary
NOTE: This is the seventh of in total 7 sub-studies related to the Ethics Committee of the Canton of Bern Ref. No. KEK-BE 2016-00674. This sub-study includes 50 participants and 8 arms, in total 350 participants will be assessed in all 7 sub-studies. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Exposure to Man-made Visible Light
- What is being tested?
- Visible light exposure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 23 participants
- Where
- 1 siteSwitzerland
- Study dates
- 1 Jun 2025to 31 Jul 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Normal color vision
- Right handed
- Written informed consent
Who cannot join
- Smoking
- Any kind of diagnosed sleep disorder or neurological or psychiatric disorder in the last 3 months
- Acute severe traumas
- Chronic diseases with the necessity for medication
- Use of recreational drugs
- Regular intake of medication that would affect the outcome measures
Show all 9Show fewer
- Regular excessive alcohol use (> 18 standard units / week)
- Transmeridian travel in the last month (crossed > 1 time zone border)
- Night shift word during the last month
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
University of Bern, Institute of Complementary Medicine
Bern, 3012
About this study
Official title: Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach
NOTE: This is the seventh of in total 7 sub-studies related to the Ethics Committee of the Canton of Bern Ref. No. KEK-BE 2016-00674. This sub-study includes 50 participants and 8 arms, in total 350 participants will be assessed in all 7 sub-studies.
General study information: This is a randomized, cross-over, quantitative study, which investigates physiological variables, mood, and affect of healthy participants in response to colored light exposure. The Participants take part in 5-8 arms and are exposed to colored light only, or are additionally asked to solve cognitive tasks during the colored light exposure. Primary aim is to measure the change in several physiological variables, mood, and affect during colored light exposure of 15 or 45 minutes. The risk for the participants is negligible and comparable to the risk during daily life.
- Conditions
- Exposure to Man-made Visible Light
- Being tested
- Visible light exposure
- Keywords
- cerebral oxygen metabolism, functional near-infrared spectroscopy, partial pressure of carbon dioxide, heart rate variability, blood pressure, affect, mood, respiration, systematic randomized cross-over study, systemic physiology, electro-dermal activity, pulse-respiratory quotient
- Medical subject headings
- Respiratory Aspiration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Visible light exposureOther
Subjects will be exposed to visible colored light for 45 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
| Study group | Role | What they receive |
|---|---|---|
| Visible light exposure Red 30 lux | Experimental | The participants will be exposed to red LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure Red 120 lux | Experimental | The participants will be exposed to red LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure Blue 30 lux | Experimental | The participants will be exposed to blue LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure Blue 120 lux | Experimental | The participants will be exposed to blue LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure Green 30 lux | Experimental | The participants will be exposed to green LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure Green 120 lux | Experimental | The participants will be exposed to green LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure White 30 lux | Experimental | The participants will be exposed to white LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
| Visible light exposure White 120 lux | Experimental | The participants will be exposed to white LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . Receives: Other: Visible light exposure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in cerebral tissue oxygen saturation during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in cerebral hemoglobin concentration during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the heart rate variability during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the electro-dermal activity during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the blood pressure during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the partial pressure of carbon dioxide during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the respiration rate during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the heart rate during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the pulse-respiratory quotient during colored light exposure compared with a baseline and a recovery period
The pulse-respiratory quotient will be calculated as heart rate divided by the respiration rate.
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the arterial oxygen saturation during colored light exposure compared with a baseline and a recovery period
Measured: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Secondary outcomes (4)
Change in verbal fluency task performance during exposure to different colors.
A word repetition task will serve as control condition.
Measured: 1-4 weeks
Change in arithmetic task performance during exposure to different colors.
A word repetition task will serve as control condition.
Measured: 1-4 weeks
Difference in brain activity evoked from the verbal fluency task for the different colored light conditions.
A word repetition task will serve as control condition.
Measured: 1-4 weeks
Difference in brain activity evoked from the arithmetic task for the different colored light conditions.
A word repetition task will serve as control condition.
Measured: 1-4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Sep 2016 (estimated)
- Study start1 Jun 2025
- Primary completion1 Jun 2025
- Study completion31 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Exposure to Man-made Visible LightStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Bern
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Ursula Wolf, Prof. Dr., Principal investigator, University of Bern
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02919137
- Sponsor's protocol ID
- COLOR10_g
- Status last verified
- Jul 2025
- First submitted
- 24 Aug 2016
- Last updated
- 29 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Access to research data and documents will be handled according to the Manifesto to advance Data Access and Research Transparency (DART) in Switzerland, formulated at the workshop on "Improving DART in Switzerland" in Bern, November 7th, 2014.
Publications
Weinzirl J, Wolf M, Nelle M, Heusser P, Wolf U. Colored light and brain and muscle oxygenation. Adv Exp Med Biol. 2012;737:33-6. doi: 10.1007/978-1-4614-1566-4_5. No abstract available.
PubMed 22259078Weinzirl J, Wolf M, Heusser P, Nelle M, Wolf U. Effects of changes in colored light on brain and calf muscle blood concentration and oxygenation. ScientificWorldJournal. 2011 Jun 9;11:1216-25. doi: 10.1100/tsw.2011.118.
PubMed 21666991
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach
- ClinicalTrials.gov ID
- NCT02919137
- Acronym / sponsor ID
- COLOR10_g
- Conditions
- Exposure to Man-made Visible Light
- Keywords
- cerebral oxygen metabolism, functional near-infrared spectroscopy, partial pressure of carbon dioxide, heart rate variability, blood pressure, affect, mood, respiration
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 23 participants (actual)
- Lead sponsor
- University of BernUniversity, hospital or other
- Study start
- 1 Jun 2025 (actual)
- Primary completion
- 1 Jun 2025 (actual)
- Study completion
- 31 Jul 2027 (estimated)
- First posted
- 29 Sep 2016 (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.
NOTE: This is the seventh of in total 7 sub-studies related to the Ethics Committee of the Canton of Bern Ref. No. KEK-BE 2016-00674. This sub-study includes 50 participants and 8 arms, in total 350 participants will be assessed in all 7 sub-studies.
General study information: This is a randomized, cross-over, quantitative study, which investigates physiological variables, mood, and affect of healthy participants in response to colored light exposure. The Participants take part in 5-8 arms and are exposed to colored light only, or are additionally asked to solve cognitive tasks during the colored light exposure. Primary aim is to measure the change in several physiological variables, mood, and affect during colored light exposure of 15 or 45 minutes. The risk for the participants is negligible and comparable to the risk during daily life.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Visible light exposure Red 30 lux | Experimental | Other: Visible light exposureThe participants will be exposed to red LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure Red 120 lux | Experimental | Other: Visible light exposureThe participants will be exposed to red LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure Blue 30 lux | Experimental | Other: Visible light exposureThe participants will be exposed to blue LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure Blue 120 lux | Experimental | Other: Visible light exposureThe participants will be exposed to blue LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure Green 30 lux | Experimental | Other: Visible light exposureThe participants will be exposed to green LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure Green 120 lux | Experimental | Other: Visible light exposureThe participants will be exposed to green LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure White 30 lux | Experimental | Other: Visible light exposureThe participants will be exposed to white LED light at a illuminance of 30 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
| Visible light exposure White 120 lux | Experimental | Other: Visible light exposureThe participants will be exposed to white LED light at a illuminance of 120 lux at eye level for 45 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will perform cognitive tests (verbal fluency task, arithmetic task, word repetition task) during the colored light exposure and hyperventilation and hypoventilation tasks . |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Normal color vision
- Right handed
- Written informed consent
Key exclusion criteria (9 listed)
- Smoking
- Any kind of diagnosed sleep disorder or neurological or psychiatric disorder in the last 3 months
- Acute severe traumas
- Chronic diseases with the necessity for medication
- Use of recreational drugs
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 |
|---|---|---|
| Visible light exposureSubjects will be exposed to visible colored light for 45 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans. | Other | Visible light exposure Blue 120 lux, Visible light exposure Blue 30 lux, Visible light exposure Green 120 lux, Visible light exposure Green 30 lux, Visible light exposure Red 120 lux, Visible light exposure Red 30 lux, Visible light exposure White 120 lux, Visible light exposure White 30 lux |
Primary outcome
Change in cerebral tissue oxygen saturation during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in cerebral hemoglobin concentration during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the heart rate variability during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the electro-dermal activity during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the blood pressure during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the partial pressure of carbon dioxide during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the respiration rate during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the heart rate during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the pulse-respiratory quotient during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
The pulse-respiratory quotient will be calculated as heart rate divided by the respiration rate.
Change of the arterial oxygen saturation during colored light exposure compared with a baseline and a recovery period
Time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
4 secondary outcomes
Change in verbal fluency task performance during exposure to different colors.
Time frame: 1-4 weeks
Change in arithmetic task performance during exposure to different colors.
Time frame: 1-4 weeks
Difference in brain activity evoked from the verbal fluency task for the different colored light conditions.
Time frame: 1-4 weeks
Difference in brain activity evoked from the arithmetic task for the different colored light conditions.
Time frame: 1-4 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2025.
- Background: PubMed 22259078Weinzirl J, Wolf M, Nelle M, Heusser P, Wolf U. Colored light and brain and muscle oxygenation. Adv Exp Med Biol. 2012;737:33-6. doi: 10.1007/978-1-4614-1566-4_5. No abstract available.
- Background: PubMed 21666991Weinzirl J, Wolf M, Heusser P, Nelle M, Wolf U. Effects of changes in colored light on brain and calf muscle blood concentration and oxygenation. ScientificWorldJournal. 2011 Jun 9;11:1216-25. doi: 10.1100/tsw.2011.118.
- Individual participant dataSharing planned: Undecided. Access to research data and documents will be handled according to the Manifesto to advance Data Access and Research Transparency (DART) in Switzerland, formulated at the workshop on "Improving DART in Switzerland" in Bern, November 7th, 2014.
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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.
Ursula Wolf, Prof. Dr. principal investigator
University of Bern
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Visible light exposure in people with Exposure to Man-made Visible Light, run by University of Bern at 1 site in Switzerland.
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 3 inclusion and 9 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: under way, not looking for participants, as of the sponsor's last update on 29 Jul 2025. 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 Switzerland. 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?
This study is still under way. Results are not available in the source record yet.
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?
Change in cerebral tissue oxygen saturation during colored light exposure compared with a baseline and a recovery period (time frame: 43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)). The study lists 10 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 NCT02919137, which also lists 2 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 29 Jul 2025.