ClinicalTrials.Veeva

Menu

Effects of Different Colors of Light on Human Physiology

Mass General Brigham logo

Mass General Brigham

Status

Completed

Conditions

Healthy
Circadian Rhythm

Treatments

Device: Monochromatic visible light exposure

Study type

Interventional

Funder types

Other
NIH

Identifiers

NCT00200863
R01AT002129-01 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

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.

Full 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.

Enrollment

47 patients

Sex

All

Ages

18 to 30 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

  • Free from any acute, chronic or debilitating medical, psychological, or ophthalmological conditions
  • Drug-free (including caffeine, nicotine, and alcohol) for entire study duration

Exclusion criteria

  • 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 design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

None (Open label)

47 participants in 6 patient groups

1
Experimental group
Description:
420 nm light
Treatment:
Device: Monochromatic visible light exposure
2
Experimental group
Description:
480 nm
Treatment:
Device: Monochromatic visible light exposure
3
Experimental group
Description:
507 nm
Treatment:
Device: Monochromatic visible light exposure
4
Experimental group
Description:
555 nm
Treatment:
Device: Monochromatic visible light exposure
5
Experimental group
Description:
620 nm
Treatment:
Device: Monochromatic visible light exposure
6
Experimental group
Description:
460 nm
Treatment:
Device: Monochromatic visible light exposure

Trial contacts and locations

1

Loading...

Data sourced from clinicaltrials.gov

Clinical trials

Find clinical trialsTrials by location
© Copyright 2025 Veeva Systems