Trial reportProceedings of the National Academy of Sciences of the United States of America2007
Entrainment of the human circadian pacemaker to longer-than-24-h days.
Trial report in Proceedings of the National Academy of Sciences of the United States of America, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 92 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
92 citing papers in PubMed, 1 synthesis or guideline pooled it, 203 citations in OpenAlex.
- A systematic review of the amount and timing of light in association with objective and subjective sleep outcomes in community-dwelling adults.Sleep health · 2019Pooled it
- Trial
- Characterizing the temporal Dynamics of Melatonin and Cortisol Changes in Response to Nocturnal Light Exposure.Scientific reports · 2019Trial
- Circadian phase resetting by a single short-duration light exposure.JCI insight · 2017Trial
- Temporal integration of light flashes by the human circadian system.The Journal of clinical investigation · 2016Trial
- Trial
- Combination of light and melatonin time cues for phase advancing the human circadian clock.Sleep · 2013Trial
- Human responses to bright light of different durations.The Journal of physiology · 2012Trial
- Variable Morning Melatonin Profiles Limit Determination of Dim-Light Melatonin Offset in Preschool-Aged Children.Journal of biological rhythms · 2026Article
- Temporal Dynamics of Sleep During Bright-Light Therapy for Depression and Their Relation to Symptom Improvement.Clocks & sleep · 2026Article
- Association of circadian rhythms, MTNR1B, BMAL1, BMAL2, and CRY2 gene polymorphisms and their interactions with type 2 diabetes in coal miners.Frontiers in endocrinology · 2026Article
- Influence of circadian alignment and sleep timing variability on sex-specific inflammatory markers in healthy adults.American journal of physiology. Heart and circulatory physiology · 2025Article
- The relationship between sleep and circadian-sleep phase angles based on dim light melatonin onset predicted from light and activity data.Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine · 2025Article
- CHRONO regulates the circadian clock via the REV-ERBα - BMAL1 loop.Npj biological timing and sleep · 2025Article
- Light levels in a modern intensive care unit: Impact of time of year, window directionality, and outdoor light levels.Chronobiology international · 2025Article
- Evidence that the woman's ovarian cycle is driven by an internal circamonthly timing system.Science advances · 2024Article
- Spatiotemporal light exposure modeling for environmental circadian misalignment and solar jetlag.Environmental epidemiology (Philadelphia, Pa.) · 2024Article
- The sleep-circadian interface: A window into mental disorders.Proceedings of the National Academy of Sciences of the United States of America · 2024Review
- Distribution of dim light melatonin offset (DLMOff) and phase relationship to waketime in healthy adults and associations with chronotype.Sleep health · 2024Article
- A perspective on the Festschrift of Charles A. Czeisler, PhD MD.Sleep health · 2024Article
32 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 3 institutions in 2 countries.
Funding
Abstract
Entrainment of the circadian pacemaker to the light:dark cycle is necessary for rhythmic physiological functions to be appropriately timed over the 24-h day. Nonentrainment results in sleep, endocrine, and neurobehavioral impairments. Exposures to intermittent bright light pulses have been reported to phase shift the circadian pacemaker with great efficacy. Therefore, we tested the hypothesis that a modulated light exposure (MLE) with bright light pulses in the evening would entrain subjects to a light:dark cycle 1 h longer than their own circadian period (tau). Twelve subjects underwent a 65-day inpatient study. Individual subject's circadian period was determined in a forced desynchrony protocol. Subsequently, subjects were released into 30 longer-than-24-h days (daylength of tau + 1 h) in one of three light:dark conditions: (i) approximately 25 lux; (ii) approximately 100 lux; and (iii) MLE: approximately 25 lux followed by approximately 100 lux, plus two 45-min bright light pulses of approximately 9,500 lux near the end of scheduled wakefulness. We found that lighting levels of approximately 25 lux were insufficient to entrain all subjects tested. Exposure to approximately 100 lux was sufficient to entrain subjects, although at a significantly wider phase angle compared with baseline. Exposure to MLE was able to entrain the subjects to the imposed sleep-wake cycles but at a phase angle comparable to baseline. These results suggest that MLE can be used to entrain the circadian pacemaker to non-24-h days. The implications of these findings are important because they could be used to treat circadian misalignment associated with space flight and circadian rhythm sleep disorders such as shift-work disorder.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.