SleepLS4NCT07889466
Circadian-informed Optimal Bedtime
A study testing Optimal Bedtime in people with Sleep and Alertness, Fatigue, Mood, and Performance, run by Massachusetts Institute of Technology at 1 site in United States.
Trial summary
The goal of this interventional study is to test whether circadian-informed bedtime recommendations can improve sleep, next-day psychomotor vigilance, and subjective well-being among healthy adults. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Sleep, Alertness, Fatigue, Mood, and Performance, Well-being
- What is being tested?
- Optimal Bedtime
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 203 participants
- Where
- 1 siteUnited States
- Study dates
- 11 Jun 2025to 30 Jan 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adults aged 18 to 60
- English-speaking
- Residence of the U.S.
- Owner of a Samsung Galaxy Watch paired with an Android phone
Who cannot join
- Shift work schedule
- Current smoker or currently using recreational drug
- Diagnosis of any sleep or circadian rhythm disorder
- Currently taking medications that may inhibit melatonin production
- History of traumatic brain injury, stroke, or seizure
- Plan of traveling across time zones during the study
Trial locations and contacts
1 site in 1 country.
United States1 site
Massachusetts Institute of Technology
Cambridge, Massachusetts, 02139
About this study
Official title: New Personalized Smart Bedtime Intervention Based on the Data Collected From Samsung Galaxy Watch.
The goal of this interventional study is to test whether circadian-informed bedtime recommendations can improve sleep, next-day psychomotor vigilance, and subjective well-being among healthy adults. The main questions it aims to answer are:
- Can Optimal Bedtime derived from data collected by a consumer smartwatch increase the objective total sleep time?
- Can Optimal Bedtime derived from data collected by a consumer smartwatch reduce the count of lapse in a next-day Psychomotor Vigilance Task?
- Can Optimal Bedtime derived from data collected by a consumer smartwatch increase subjective sleep quality?
Read more
Researchers will compare Optimal Bedtime with a placebo bedtime and an unguided baseline in a cross-over design.
Participants will:
- Be randomized 1:1 to either Optimal Bedtime then placebo or placebo then Optimal Bedtime.
- Wear a consumer smartwatch for 6 weeks, 2 weeks in each of baseline, Optimal Bedtime, and placebo.
- Complete a Psychomotor Vigilance Task and a subjective well-being survey every morning.
- Conditions
- Sleep, Alertness, Fatigue, Mood, and Performance, Well-being
- Being tested
- Optimal Bedtime, Placebo
- Medical subject headings
- Fatigue
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Optimal BedtimeBehavioural
Also called Smart Bedtime
Optimal Bedtime recommendations informed by the estimated dim-light melatonin onset from a consumer smartwatch, adjusted for the desired total sleep time of the participant and delivered via a mobile application twice a day.
PlaceboBehavioural
Placebo bedtime recommendations based on the desired total sleep time and desired wake-up time of the participant with a daily random jitter within ± 30 minutes, delivered via a mobile application twice a day.
| Study group | Role | What they receive |
|---|---|---|
| Optimal Bedtime then placebo | Other | Optimal Bedtime recommendation for two weeks followed by placebo bedtime recommendation for two weeks (randomized crossover) Receives: Behavioral: Optimal Bedtime; Behavioral: Placebo |
| Placebo then Optimal Bedtime | Other | Placebo bedtime recommendation for two weeks followed by Optimal Bedtime recommendation for two weeks (randomized crossover) Receives: Behavioral: Optimal Bedtime; Behavioral: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from Baseline and Placebo in Total Sleep Time
Smartwatch-derived objective total sleep time in minutes.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in the Count of Lapse in Psychomotor Vigilance Task (PVT)
Count of responses with reaction time greater than 500 milliseconds in a PVT session.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Sleep Quality
Self-reported sleep quality score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Secondary outcomes (14)
Change from Baseline and Placebo in Sleep Efficiency
Objective total sleep time divided by time in bed, in percentage points.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Sleep Fragmentation Index
Waking bouts per 100 min of objective total sleep time.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Wake After Sleep Onset
Objective total time awake after sleep onset and before wake onset, in minutes.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Deep Sleep Duration
Smartwatch-derived deep sleep duration in minutes.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Deep Sleep Percentage
Smartwatch-derived deep sleep in percentage of objective total sleep time.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Rapid Eye Movement (REM) Sleep Duration
Smartwatch-derived REM sleep duration in minutes.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Rapid Eye Movement (REM) Sleep Percentage
Smartwatch-derived REM sleep in percentage of objective total sleep time.
Measured: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Mean Response Speed
Mean reciprocal reaction time in a PVT session, in per second.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Mean Slowest-10% Response Speed
Mean reciprocal reaction time over the slowest 10% responses in a PVT session, in per second.
Measured: 6 week, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Alertness
Daily self-reported alertness score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Happiness
Self-reported happiness score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Energy
Self-reported energy score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Health
Self-reported health score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Calmness
Self-reported calmness score on a visual analogue scale of 0 to 100, higher indicating more favorable.
Measured: 6 weeks, daily in baseline, placebo, and intervention.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Oct 2026
- Study start11 Jun 2025
- Primary completion30 Jan 2026
- Study completion30 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for SleepStudies 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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomization will be used to limit bias and achieve an equal distribution of participants to the two crossover arms (intervention then placebo or placebo then intervention).
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 203 participants (actual)
Sponsor and investigators
- Lead sponsor
- Massachusetts Institute of Technology
- Sponsor type
- University, hospital or other
- Collaborators
- Samsung Research America
- Responsible party
- Sponsor
- Investigators
- Rosalind W Picard, Sc. D., Principal investigator, Massachusetts Institute of Technology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07889466
- Sponsor's protocol ID
- 2411001487
- Acronym
- LS4
- Status last verified
- Oct 2026
- First submitted
- 15 Oct 2026
- Last updated
- 23 Oct 2026
- Results posted
- No
- 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 23 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- New Personalized Smart Bedtime Intervention Based on the Data Collected From Samsung Galaxy Watch.
- ClinicalTrials.gov ID
- NCT07889466
- Acronym / sponsor ID
- LS4 / 2411001487
- Conditions
- Sleep, Alertness, Fatigue, Mood, and Performance, Well-being
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 203 participants (actual)
- Lead sponsor
- Massachusetts Institute of TechnologyUniversity, hospital or other
- Collaborators
- Samsung Research America
- Study start
- 11 Jun 2025 (actual)
- Primary completion
- 30 Jan 2026 (actual)
- Study completion
- 30 Jan 2026 (actual)
- First posted
- 22 Oct 2026 (actual)
- 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.
The goal of this interventional study is to test whether circadian-informed bedtime recommendations can improve sleep, next-day psychomotor vigilance, and subjective well-being among healthy adults. The main questions it aims to answer are:
- Can Optimal Bedtime derived from data collected by a consumer smartwatch increase the objective total sleep time?
- Can Optimal Bedtime derived from data collected by a consumer smartwatch reduce the count of lapse in a next-day Psychomotor Vigilance Task?
- Can Optimal Bedtime derived from data collected by a consumer smartwatch increase subjective sleep quality?
Researchers will compare Optimal Bedtime with a placebo bedtime and an unguided baseline in a cross-over design.
Participants will:
- Be randomized 1:1 to either Optimal Bedtime then placebo or placebo then Optimal Bedtime.
- Wear a consumer smartwatch for 6 weeks, 2 weeks in each of baseline, Optimal Bedtime, and placebo.
- Complete a Psychomotor Vigilance Task and a subjective well-being survey every morning.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomization will be used to limit bias and achieve an equal distribution of participants to the two crossover arms (intervention then placebo or placebo then intervention).
| Arm | Type | Receives |
|---|---|---|
| Optimal Bedtime then placebo | Other | Behavioral: Optimal Bedtime, Behavioral: PlaceboOptimal Bedtime recommendation for two weeks followed by placebo bedtime recommendation for two weeks (randomized crossover) |
| Placebo then Optimal Bedtime | Other | Behavioral: Optimal Bedtime, Behavioral: PlaceboPlacebo bedtime recommendation for two weeks followed by Optimal Bedtime recommendation for two weeks (randomized crossover) |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Adults aged 18 to 60
- English-speaking
- Residence of the U.S.
- Owner of a Samsung Galaxy Watch paired with an Android phone
Key exclusion criteria (6 listed)
- Shift work schedule
- Current smoker or currently using recreational drug
- Diagnosis of any sleep or circadian rhythm disorder
- Currently taking medications that may inhibit melatonin production
- History of traumatic brain injury, stroke, or seizure
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 |
|---|---|---|
| Optimal BedtimeAlso: Smart BedtimeOptimal Bedtime recommendations informed by the estimated dim-light melatonin onset from a consumer smartwatch, adjusted for the desired total sleep time of the participant and delivered via a mobile application twice a day. | Behavioural | Optimal Bedtime then placebo, Placebo then Optimal Bedtime |
| PlaceboPlacebo bedtime recommendations based on the desired total sleep time and desired wake-up time of the participant with a daily random jitter within ± 30 minutes, delivered via a mobile application twice a day. | Behavioural | Optimal Bedtime then placebo, Placebo then Optimal Bedtime |
Primary outcome
Change from Baseline and Placebo in Total Sleep Time
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Smartwatch-derived objective total sleep time in minutes.
Change from Baseline and Placebo in the Count of Lapse in Psychomotor Vigilance Task (PVT)
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Count of responses with reaction time greater than 500 milliseconds in a PVT session.
Change from Baseline and Placebo in Subjective Sleep Quality
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Self-reported sleep quality score on a visual analogue scale of 0 to 100, higher indicating more favorable.
14 secondary outcomes
Change from Baseline and Placebo in Sleep Efficiency
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Sleep Fragmentation Index
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Wake After Sleep Onset
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Deep Sleep Duration
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Deep Sleep Percentage
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Rapid Eye Movement (REM) Sleep Duration
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Rapid Eye Movement (REM) Sleep Percentage
Time frame: 6 weeks, nightly in baseline, placebo, and intervention.
Change from Baseline and Placebo in Mean Response Speed
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Mean Slowest-10% Response Speed
Time frame: 6 week, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Alertness
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Happiness
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Energy
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Health
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Change from Baseline and Placebo in Subjective Calmness
Time frame: 6 weeks, daily in baseline, placebo, and intervention.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2026.
- Individual participant dataSharing planned: No
Related trials for Sleep
Recruiting
A Clinical Trial to Evaluate the Effects of Adrenal Adapt on Sleep Quality, Daytime Energy, Stress Resilience, and Cognitive Performance.
Improves Daytime Energy Levels, Reduces Afternoon Energy Crashes and Midday Fatigue
Recruiting
The Sleep2BWell Trial
Blood Pressure, Sleep Health
Recruiting
The Effects of Successful OSA Treatment on Memory and AD Biomarkers in Older Adults Study
Obstructive Sleep Apnea, Cognitive Decline
Not yet recruitingObservational study
Stress, Coping, and Sleep Health Study
Sleep
Recruiting
Smith Magenis Syndrome and Autism Spectrum Disorders
Smith-Magenis Syndrome, Autism Spectrum Disorder
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.
Rosalind W Picard, Sc. D. principal investigator
Massachusetts Institute of Technology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Optimal Bedtime in people with Sleep and Alertness, Fatigue, Mood, and Performance, run by Massachusetts Institute of Technology 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 4 inclusion and 6 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 23 Oct 2026. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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 from Baseline and Placebo in Total Sleep Time (time frame: 6 weeks, nightly in baseline, placebo, and intervention.). 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 23 Oct 2026.