An observational study in Sleep Wake Disorders, Sleep Disorders, Circadian Rhythm and Sleep Disorders, Intrinsic, sponsored by Brigham and Women's Hospital. Terminated at 1 site in United States. Open to participants aged 18 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-08-03.
Sponsored by Brigham and Women's Hospital · Observational
Study investigators want to learn more about the underlying biological clock and to see if the timing of that clock can be estimated from a single blood sample.
There is an urgent need for a practical way to assess circadian timing accurately in both general and sleep medicine. The study is designed to assess the levels of different biomarkers in the blood taken from frequent samples across three separate sleep-wake conditions - Conventional/Normal sleep-wake conditions (baseline), extended wake/acute sleep deprivation (constant routine), and during irregular sleep-wake conditions (inverted day). Participants will be asked to complete medical, psychological, and sleep-wake evaluations prior to the study. Upon completion of screening, if eligible, participants will stay 7 consecutive days and nights in the sleep research laboratory within the hospital.
788 studies on the registry are indexed under Sleep Wake Disorders; 186 are open to participants now.
This study's enrollment of 15 is below the median of 114 across 215 observational studies indexed under Sleep Wake Disorders.
Browse Sleep Wake Disorders studies →Brigham and Women's Hospital is the lead sponsor of 1,236 studies on the registry; 224 are open to participants now.
Of its 116 completed or terminated interventional studies of FDA-regulated products, 64 (55%) have results posted.
Counted across the registry records on this site, refreshed daily.
Healthy volunteers will be recruited from the surrounding community.
Exclusion Criteria:
Study participants will have one inverted day when they are scheduled to sleep \~12h opposite their usual sleep time.
Study participants will spend \~28-50 hours awake, inactive, sitting in bed, in constant lighting and temperature.
Circadian Phase Timing by BodyTime Assay - Baseline Segment
Circadian phase will be predicted by the BodyTime assay during the baseline segment (study day 3) and will be compared to conventional phase assessment methods.
Time frame: Baseline Segment (Study day 3)
Circadian Phase Timing by BodyTime Assay - Constant Routine
Circadian phase will be predicted by the BodyTime assay during the Constant Routine (study days 4-5) and will be compared to conventional phase assessment methods.
Time frame: During Constant Routine (Study days 4-5)
Circadian Phase Timing by BodyTime Assay - Inverted Day
Circadian phase will be predicted by the BodyTime assay during the Inverted Day (study days 6-7) and will be compared to conventional phase assessment methods.
Time frame: Inverted Day (Study days 6-7)
This study is terminated, as verified in Jul 2025. You cannot join it, but the record below documents what was studied.
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Brigham and Women's Hospital