Investigating how light and meal timing affect body clocks

Determining the Role of Photic and Non-photic Time Cues in Resetting Circadian Rhythms in Humans

Not applicable Interventional Brigham and Women's Hospital · NCT05276739

This study is testing whether changing the timing of bright light exposure or meal times can help reset body clocks and improve health in healthy young adults.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment48 (estimated)
Ages18 Years to 30 Years
SexAll
SponsorBrigham and Women's Hospital Academic / other
Locations1 site (Boston, Massachusetts)
Trial IDNCT05276739 on ClinicalTrials.gov

What this trial studies

This study aims to identify whether light exposure or meal timing serves as the primary cue for resetting circadian rhythms related to melatonin and metabolic outcomes. It will involve a randomized controlled trial with 48 healthy young adults, manipulating the timing of 6.5-hour bright light exposure and time-restricted eating. The research will compare the effects of these cues on circadian rhythms of circulating lipids and melatonin, providing insights into how these factors influence human biological clocks. The study builds on previous successful experiments that explored the relationship between light exposure and circadian rhythms.

Who should consider this trial

Good fit: Ideal candidates are healthy young adults aged 18-30 who can maintain a consistent sleep schedule and refrain from substances that may affect sleep or alertness.

Not a fit: Patients with sleep disorders, psychiatric conditions, or those on medications affecting sleep or light sensitivity may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved strategies for managing sleep and metabolic health through better timing of light exposure and meals.

How similar studies have performed: Previous studies have shown success in understanding the effects of light on circadian rhythms, making this approach both relevant and promising.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Aged between 18-30 years
* Healthy (no medical, psychiatric or sleep disorders;
* Non-smoking for at least 6 months;
* Body Mass Index of \>18 or \<30 kg/m2;
* Able to maintain 8-hour consistent sleep schedule during the study
* Able to refrain from caffeine, alcohol, medication and supplements during the study

Exclusion Criteria:

* History of alcohol or substance abuse;
* Positive result on drugs of abuse urine toxicology;
* Current or past history of sleep disorders, including but not limited to obstructive sleep apnea, narcolepsy, insomnia, or any significant sleep complaint
* Psychiatric disorder, or first degree relative with a psychiatric disorder
* Recent acute or chronic medical disorder
* Use of drugs or medication (birth control OK) likely to affect sleep, alertness or light sensitivity, as determined by the investigators
* Visual disorder, including but not limited to color blindness, or family history of glaucoma
* Pregnancy or lactation
* Shift work (past 3 years)
* Transmeridian travel (2 or more time zones) in the past 3 months
* Any other reason as determine by the Principal Investigator

Where this trial is running

Boston, Massachusetts

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Light ExposureMeal Timing
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.