Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach (Substudy 2 of 7)

Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach

NOTE: This is the second 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 6 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 Overview

• Status: Completed
• Conditions: Exposure to Man-made Visible Light
• Intervention / Treatment: Other: Visible light exposure

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Bern, Switzerland, 3012
    • University of Bern, Institute of Complementary Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Normal color vision
• Right handed
• Written informed consent

Exclusion Criteria:

• 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
• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Visible light exposure Green 30 lux; The participants will be exposed to green LED light at a illuminance of 30 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure Green 120 lux; The participants will be exposed to green LED light at a illuminance of 120 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure Yellow 30 lux; The participants will be exposed to yellow LED light at a illuminance of 30 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure Yellow 120 lux; The participants will be exposed to yellow LED light at a illuminance of 120 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure Violet 30 lux; The participants will be exposed to violet LED light at a illuminance of 30 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure Violet 120 lux; The participants will be exposed to violet LED light at a illuminance of 120 lux at eye level for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in cerebral tissue oxygen saturation during colored light exposure compared with a baseline and a recovery period		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		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		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.	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		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	3 hemoglobin concentrations will be analyzed: of oxygenated hemoglobin, of deoxygenated hemoglobin, and of total hemoglobin.	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	The tonic and phasic parts of the electro-dermal activity will be analyzed.	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	The systolic, diastolic, and mean arterial pressure will be analyzed.	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	The partial pressure of carbon dioxide will be assessed by the end-tidal partial pressure of carbon dioxide of the exhalation air.	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	Heart rate variability variables are: the standard deviation of the NN intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD), the power of the high-frequency component (HF, 0.15-0.4 Hz), the power of the low-frequency component (LF, 0.04-0.15 Hz), the power of the very low-frequency component (VLF, <0.04 Hz), normalized LF and HF components, and the LF/HF ratio.	43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)

Collaborators and Investigators

• Sponsor: University of Bern
• Investigators: Principal Investigator: Ursula Wolf, Prof. Dr., University of Bern

Publications and helpful links

General 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.
• Weinzirl 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.

Helpful Links

• Link to further information on the study

Study record dates

Study Major Dates

• Study Start (Actual): June 26, 2017
• Primary Completion (Actual): May 31, 2018
• Study Completion (Actual): August 30, 2021

Study Registration Dates

• First Submitted: August 24, 2016
• First Submitted That Met QC Criteria: August 24, 2016
• First Posted (Estimate): August 30, 2016

Study Record Updates

• Last Update Posted (Actual): September 17, 2021
• Last Update Submitted That Met QC Criteria: September 16, 2021
• Last Verified: September 1, 2021

More Information

Terms related to this study

• Keywords: blood pressure; functional near-infrared spectroscopy; heart rate variability; mood; affect; respiration; cerebral oxygen metabolism; partial pressure of carbon dioxide; systematic randomized cross-over study; systemic physiology; electro-dermal activity; pulse-respiratory quotient
• Other Study ID Numbers: COLOR10_b

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No