ArticleJournal of biological rhythms2018
White Light During Daytime Does Not Improve Alertness in Well-rested Individuals.
Article in Journal of biological rhythms, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 16 papers, 1 of them a synthesis that pooled it.
What it found
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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.
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Who cites it
16 citing papers in PubMed, 1 synthesis or guideline pooled it, 53 citations in OpenAlex.
- Ocular light and optical radiation exposure as a modifiable environmental determinant of health: expert consensus on research gaps and priorities.BMC medicine · 2026Guideline
- Daytime melatonin and light independently affect human alertness and body temperature.Journal of pineal research · 2019Trial
- Bright light exposure reduces negative affect and modulates EEG activity in sleep-deprived and well-rested adolescents.Frontiers in behavioral neuroscience · 2025Article
- Light Exposure on Alertness after Wake-Up in Healthy Men: Comparing Dim, Bright, Red, and Blue Light.Neuropsychobiology · 2024Article
- Associations between light exposure and sleep timing and sleepiness while awake in a sample of UK adults in everyday life.Proceedings of the National Academy of Sciences of the United States of America · 2023Article
- Brighter Time: A Smartphone App Recording Cognitive Task Performance and Illuminance in Everyday Life.Clocks & sleep · 2022Article
- Objective Measures of Immediate "Energizing" Effect of Light: Studies Review and Data Analysis.Clocks & sleep · 2022Review
- Bright Light Increases Alertness and Not Cortisol in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light (I).Journal of biological rhythms · 2022Article
- Effects of Daytime Electric Light Exposure on Human Alertness and Higher Cognitive Functions: A Systematic Review.Frontiers in psychology · 2021Review
- Human-Centric Lighting: Foundational Considerations and a Five-Step Design Process.Frontiers in neurology · 2021Review
- Does Bright Light Counteract the Post-lunch Dip in Subjective States and Cognitive Performance Among Undergraduate Students?Frontiers in public health · 2021Article
- Temporal Dynamics of Subjective and Objective Alertness During Exposure to Bright Light in the Afternoon for 5 h.Frontiers in physiology · 2021Article
- The Role of Daylight for Humans: Gaps in Current Knowledge.Clocks & sleep · 2020Article
- Living in Biological Darkness: Objective Sleepiness and the Pupillary Light Responses Are Affected by Different Metameric Lighting Conditions during Daytime.Journal of biological rhythms · 2019Article
- Light, Alertness, and Alerting Effects of White Light: A Literature Overview.Journal of biological rhythms · 2018Review
- Investigation of Dose-Response Relationships for Effects of White Light Exposure on Correlates of Alertness and Executive Control during Regular Daytime Working Hours.Journal of biological rhythms · 2018Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Broad-spectrum light applied during the night has been shown to affect alertness in a dose-dependent manner. The goal of this experiment was to investigate whether a similar relationship could be established for light exposure during daytime. Fifty healthy participants were subjected to a paradigm (0730-1730 h) in which they were intermittently exposed to 1.5 h of dim light (<10 lux) and 1 h of experimental light (24-2000 lux). The same intensity of experimental light was used throughout the day, resulting in groups of 10 subjects per intensity. Alertness was assessed with subjective and multiple objective measures. A significant effect of time of day was found in all parameters of alertness ( p < 0.05). Significant dose-response relationships between light intensity and alertness during the day could be determined in a few of the parameters of alertness at some times of the day; however, none survived correction for multiple testing. We conclude that artificial light applied during daytime at intensities up to 2000 lux does not elicit significant improvements in alertness in non-sleep-deprived subjects.
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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.