Glucose IntoleranceNCT04868539
Influence of Nocturnal Light Exposure on the Impairment of Glucose Tolerance Induced by Chronic Sleep Restriction
A study testing Sleep Restriction with ALAN first, then Sleep Restriction without ALAN and Sleep Restriction without ALAN first, then sleep restriction with ALAN in people with Glucose Intolerance and Sleep Deprivation, run by Brigham and Women's Hospital at 1 site in United States.
Trial summary
This project is designed to test for the first time whether glucose metabolism is differentially impaired by sleep restriction with and without additional exposure to artificial light at night (ALAN). Read more about this study
- Who is it for?
- Ages 20 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Glucose Intolerance, Sleep Deprivation, Sleep
- What is being tested?
- Sleep Restriction with ALAN first, then Sleep Restriction without ALAN and Sleep Restriction without ALAN first, then sleep restriction with ALAN
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Mar 2022to 30 May 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 20 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adults with conventional and regular sleep-wake timing
- Non-smokers
- Completion of medical, psychological, and sleep screening tests
- Able to spend 33 consecutive days/nights in the laboratory
- Normal color vision
Who cannot join
- History of neurological or psychiatric disorder
- History of sleep disorder or regular use of sleep-promoting medication
- Current prescription, herbal, or over-the-counter medication use
- Traveling across 2 or more time zones within past 3 months
- Donating blood within past 8 weeks
- Worked night or rotating shift work within past 3 years
Show all 9Show fewer
- Hearing impairment, visual impairment
- History of eye trauma or surgery
- Drug or alcohol dependency
Trial locations and contacts
1 site in 1 country.
United States1 site
Brigham and Women's Hospital
Boston, Massachusetts, 02115
About this study
This project is designed to test for the first time whether glucose metabolism is differentially impaired by sleep restriction with and without additional exposure to artificial light at night (ALAN).
Read the detailed description
Laboratory studies have shown that sleep restriction to 4-6h per night for durations varying from one to 14 days reduces glucose tolerance in otherwise healthy adults, but the mechanisms by which insufficient sleep impairs glucose metabolism are still unknown. Current theories are based on the premise that the adverse metabolic consequences are caused by reduction in the duration of sleep per se. However, sleep curtailment is typically accompanied by longer exposure to artificial light at night (ALAN), which is an environmental endocrine disrupter that profoundly disrupts circadian rhythms.
The investigators have previously reported that acute circadian misalignment induced hyperglycemia comparable to pre-diabetic states in a third of otherwise healthy participants. Since then, the investigators have shown that even when the circadian phase of participants was realigned, prior exposure to 2 ½ weeks of chronic sleep restriction combined with a history of recurrent circadian disruption induced even more deleterious effects on glucose metabolism, in which pancreatic beta cells failed to respond adequately to increased glucose levels. Moreover, both night and rotating shift work (which induce circadian disruption) are associated with increased risk for metabolic problems. Night shifts can lead to acute increases in glucose and insulin levels, although some studies report reduced insulin release in response to meals consumed during the night. Given that circadian disruption has been shown to independently adversely affect metabolism, and exposure to ALAN adversely impacts metabolism in animals, it is important to understand the extent to which circadian disruption contributes to the observed impact of sleep curtailment on metabolism. No previous studies of the metabolic impact of sleep restriction in humans have controlled for this additional exposure to ALAN, thus confounding the effects of sleep restriction with the effects of circadian disruption caused by extended exposure to ALAN.
- Conditions
- Glucose Intolerance, Sleep Deprivation, Sleep
- Being tested
- Sleep Restriction with ALAN first, then Sleep Restriction without ALAN, Sleep Restriction without ALAN first, then sleep restriction with ALAN
- Keywords
- Chronic Sleep Restriction, Artificial Light At Night, Glucose Intolerance, Melatonin, Sleep
- Medical subject headings
- Glucose Intolerance, Sleep Deprivation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sleep Restriction with ALAN first, then Sleep Restriction without ALANOther
Also called ALAN first
Sleep restriction with 90 lux lighting for 19hr/day first, followed by Sleep restriction with 90 lux lighting for 14hr/day
Sleep Restriction without ALAN first, then sleep restriction with ALANOther
Also called ALAN second
Sleep restriction with 90 lux lighting for 14hr/day first, followed by Sleep restriction with 90 lux lighting for 19hr/day
| Study group | Role | What they receive |
|---|---|---|
| Sleep Restriction with ALAN, then Sleep Restriction without ALAN | Experimental | Participants first received Sleep Restriction with extended duration Artificial Light At Night (ALAN), during which sleep episodes were shortened to 5 hours and participants remained in room lighting for the full wake episode (19h room light, 5h darkness). After a washout of 10 days, participants received Sleep Restriction without ALAN, during which sleep episodes were shortened to 5 hours but participants were kept in dim light for the extra time awake (14h room light, 5h dim light, 5h darkness). Receives: Other: Sleep Restriction with ALAN first, then Sleep Restriction without ALAN |
| Sleep Restriction without ALAN, then Sleep Restriction with ALAN | Experimental | Participants first received Sleep Restriction without extended duration Artificial Light At Night (ALAN), during which sleep episodes were shortened to 5 hours but participants were kept in dim light for the extra time awake (14h room light, 5h dim light, 5h darkness). After a washout of 10 days, participants received Sleep Restriction with extended duration ALAN, during which sleep episodes were shortened to 5 hours and participants remained in room lighting for the full wake episode (19h room light, 5h darkness). Receives: Other: Sleep Restriction without ALAN first, then sleep restriction with ALAN |
What is being measured
The primary outcome is the main question the study is designed to answer.
Impairment of Insulin Sensitivity
Insulin sensitivity (Si) is assessed via minimal model analysis, a mathematical model developed by Bergman and colleagues. Higher values represent better insulin sensitivity and lower values represent impaired insulin sensitivity.
The mean change in Si between exposure and baseline is reported for each arm.
Measured: Change between Study Day 7 vs. Study Day 15 and Study Day 24 vs. Study Day 32
Impairment of Glucose Tolerance
Test the hypothesis that exposure to one week of sleep restriction with concurrent exposure to extended duration ALAN (LD 19:5) will induce greater impairment of glucose tolerance than exposure to one week of sleep restriction without extended duration ALAN (LD 14:10). Glucose tolerance will be calculated as the area under the curve from minutes 0-120 following a mixed meal tolerance test
Measured: Change between Study Day 6 vs. Study Day 14 and Study Day 23 vs. Study Day 31
Duration of Nocturnal Melatonin Secretion
Test the hypothesis that exposure to one week of sleep restriction with concurrent exposure to extended duration ALAN (LD 19:5) will acutely reduce the duration of nocturnal melatonin secretion as compared to baseline more than exposure to one week of sleep restriction without extended duration ALAN (LD 14:10). Duration of nocturnal melatonin secretion will be determined by the duration of time at which melatonin levels are above a threshold calculated as 25% of peak-to-trough amplitude at baseline in dim light.
Measured: Change between Study Day 14-15 (overnight) vs. Study Day 31-32 (overnight)
Secondary outcomes (4)
Acute Insulin Response to Glucose
Acute Insulin Response as calculated with minimal model analysis, a mathematical model developed by Bergman and colleagues, and represents early insulin release in the body to manage blood glucose levels. Higher values represent a better response and lower values represent a worse response. The mean change in AIRg between exposure and baseline is reported for each arm.
Measured: Change from study day 7 to 15 compared to change from study day 24 to 32
Glucose Effectiveness
Glucose Effectiveness as calculated using minimal model analysis, a mathematical model developed by Bergman and colleagues. It represents how well the body can normalize blood glucose independent of insulin. Higher glucose effectiveness (Sg) is generally associated with better metabolic health outcomes.
Measured: Change from study day 7 to 15 vs change from study day 24 to 32
Insulin Area-under-the-curve
Insulin area under the curve (AUC) as calculated with trapezoidal method between 0-120min following mixed meal tolerance test.
Measured: Change between Study Day 6 vs. Study Day 14 and Study Day 23 vs. Study Day 31
Duration of Endogenous Melatonin Secretory Profile
Test the hypothesis that exposure to one week of sleep restriction with concurrent exposure to extended duration ALAN (LD 19:5) will reduce the duration of the endogenous melatonin secretory profile more than exposure to one week of sleep restriction without extended duration ALAN (LD 14:10). Duration of nocturnal melatonin secretion will be determined by the duration of time at which melatonin levels are above a threshold calculated as 25% of peak-to-trough amplitude at baseline in dim light.
Measured: Study Day 15-16 vs Study Day 32-33
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 May 2021
- Study start15 Mar 2022
- Primary completion20 Feb 2024
- Study completion30 May 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Glucose IntoleranceStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This study uses a within-subjects randomized crossover design to compare the effects of sleep restriction with and without ALAN on glucose metabolism. The order in which subjects undergo the two sleep interventions will be randomized.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Charles A. Czeisler, PhD, MD, Brigham and Women's Hospital
- Investigators
- Charles A Czeisler, PhD, MD, Principal investigator, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04868539
- Sponsor's protocol ID
- 2021P000961
- Status last verified
- Sep 2025
- First submitted
- 20 Apr 2021
- Last updated
- 14 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Influence of Nocturnal Light Exposure on the Impairment of Glucose Tolerance Induced by Chronic Sleep Restriction
- ClinicalTrials.gov ID
- NCT04868539
- Acronym / sponsor ID
- 2021P000961
- Conditions
- Glucose Intolerance, Sleep Deprivation, Sleep
- Keywords
- Chronic Sleep Restriction, Artificial Light At Night, Glucose Intolerance, Melatonin, Sleep
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Study start
- 15 Mar 2022 (actual)
- Primary completion
- 20 Feb 2024 (actual)
- Study completion
- 30 May 2024 (actual)
- First posted
- 3 May 2021 (actual)
- Results
- Posted 14 Oct 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This project is designed to test for the first time whether glucose metabolism is differentially impaired by sleep restriction with and without additional exposure to artificial light at night (ALAN).
Detailed description
Laboratory studies have shown that sleep restriction to 4-6h per night for durations varying from one to 14 days reduces glucose tolerance in otherwise healthy adults, but the mechanisms by which insufficient sleep impairs glucose metabolism are still unknown. Current theories are based on the premise that the adverse metabolic consequences are caused by reduction in the duration of sleep per se. However, sleep curtailment is typically accompanied by longer exposure to artificial light at night (ALAN), which is an environmental endocrine disrupter that profoundly disrupts circadian rhythms.
The investigators have previously reported that acute circadian misalignment induced hyperglycemia comparable to pre-diabetic states in a third of otherwise healthy participants. Since then, the investigators have shown that even when the circadian phase of participants was realigned, prior exposure to 2 ½ weeks of chronic sleep restriction combined with a history of recurrent circadian disruption induced even more deleterious effects on glucose metabolism, in which pancreatic beta cells failed to respond adequately to increased glucose levels. Moreover, both night and rotating shift work (which induce circadian disruption) are associated with increased risk for metabolic problems. Night shifts can lead to acute increases in glucose and insulin levels, although some studies report reduced insulin release in response to meals consumed during the night. Given that circadian disruption has been shown to independently adversely affect metabolism, and exposure to ALAN adversely impacts metabolism in animals, it is important to understand the extent to which circadian disruption contributes to the observed impact of sleep curtailment on metabolism. No previous studies of the metabolic impact of sleep restriction in humans have controlled for this additional exposure to ALAN, thus confounding the effects of sleep restriction with the effects of circadian disruption caused by extended exposure to ALAN.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- This study uses a within-subjects randomized crossover design to compare the effects of sleep restriction with and without ALAN on glucose metabolism. The order in which subjects undergo the two sleep interventions will be randomized.
| Arm | Type | Receives |
|---|---|---|
| Sleep Restriction with ALAN, then Sleep Restriction without ALAN | Experimental | Other: Sleep Restriction with ALAN first, then Sleep Restriction without ALANParticipants first received Sleep Restriction with extended duration Artificial Light At Night (ALAN), during which sleep episodes were shortened to 5 hours and participants remained in room lighting for the full wake episode (19h room light, 5h darkness). After a washout of 10 days, participants received Sleep Restriction without ALAN, during which sleep episodes were shortened to 5 hours but participants were kept in dim light for the extra time awake (14h room light, 5h dim light, 5h darkness). |
| Sleep Restriction without ALAN, then Sleep Restriction with ALAN | Experimental | Other: Sleep Restriction without ALAN first, then sleep restriction with ALANParticipants first received Sleep Restriction without extended duration Artificial Light At Night (ALAN), during which sleep episodes were shortened to 5 hours but participants were kept in dim light for the extra time awake (14h room light, 5h dim light, 5h darkness). After a washout of 10 days, participants received Sleep Restriction with extended duration ALAN, during which sleep episodes were shortened to 5 hours and participants remained in room lighting for the full wake episode (19h room light, 5h darkness). |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Healthy adults with conventional and regular sleep-wake timing
- Non-smokers
- Completion of medical, psychological, and sleep screening tests
- Able to spend 33 consecutive days/nights in the laboratory
- Normal color vision
Key exclusion criteria (9 listed)
- History of neurological or psychiatric disorder
- History of sleep disorder or regular use of sleep-promoting medication
- Current prescription, herbal, or over-the-counter medication use
- Traveling across 2 or more time zones within past 3 months
- Donating blood within past 8 weeks
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 |
|---|---|---|
| Sleep Restriction with ALAN first, then Sleep Restriction without ALANAlso: ALAN firstSleep restriction with 90 lux lighting for 19hr/day first, followed by Sleep restriction with 90 lux lighting for 14hr/day | Other | Sleep Restriction with ALAN, then Sleep Restriction without ALAN |
| Sleep Restriction without ALAN first, then sleep restriction with ALANAlso: ALAN secondSleep restriction with 90 lux lighting for 14hr/day first, followed by Sleep restriction with 90 lux lighting for 19hr/day | Other | Sleep Restriction without ALAN, then Sleep Restriction with ALAN |
Primary outcome
Impairment of Insulin Sensitivity
Time frame: Change between Study Day 7 vs. Study Day 15 and Study Day 24 vs. Study Day 32
Insulin sensitivity (Si) is assessed via minimal model analysis, a mathematical model developed by Bergman and colleagues. Higher values represent better insulin sensitivity and lower values represent impaired insulin sensitivity. The mean change in Si between exposure and baseline is reported for each arm.
Impairment of Glucose Tolerance
Time frame: Change between Study Day 6 vs. Study Day 14 and Study Day 23 vs. Study Day 31
Test the hypothesis that exposure to one week of sleep restriction with concurrent exposure to extended duration ALAN (LD 19:5) will induce greater impairment of glucose tolerance than exposure to one week of sleep restriction without extended duration ALAN (LD 14:10). Glucose tolerance will be calculated as the area under the curve from minutes 0-120 following a mixed meal tolerance test
Duration of Nocturnal Melatonin Secretion
Time frame: Change between Study Day 14-15 (overnight) vs. Study Day 31-32 (overnight)
Test the hypothesis that exposure to one week of sleep restriction with concurrent exposure to extended duration ALAN (LD 19:5) will acutely reduce the duration of nocturnal melatonin secretion as compared to baseline more than exposure to one week of sleep restriction without extended duration ALAN (LD 14:10). Duration of nocturnal melatonin secretion will be determined by the duration of time at which melatonin levels are above a threshold calculated as 25% of peak-to-trough amplitude at baseline in dim light.
4 secondary outcomes
Acute Insulin Response to Glucose
Time frame: Change from study day 7 to 15 compared to change from study day 24 to 32
Glucose Effectiveness
Time frame: Change from study day 7 to 15 vs change from study day 24 to 32
Insulin Area-under-the-curve
Time frame: Change between Study Day 6 vs. Study Day 14 and Study Day 23 vs. Study Day 31
Duration of Endogenous Melatonin Secretory Profile
Time frame: Study Day 15-16 vs Study Day 32-33
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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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.
Charles A Czeisler, PhD, MD principal investigator
Brigham and Women's Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Sleep Restriction with ALAN first, then Sleep Restriction without ALAN and Sleep Restriction without ALAN first, then sleep restriction with ALAN in people with Glucose Intolerance and Sleep Deprivation, 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 5 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: finished, as of the sponsor's last update on 14 Oct 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 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?
Yes. Results are posted in the registry (first posted 14 Oct 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Impairment of Insulin Sensitivity (time frame: Change between Study Day 7 vs. Study Day 15 and Study Day 24 vs. Study Day 32). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 14 Oct 2025.