The DOI matches its Crossref record; 45 of the 45 references it cites were found in a registry or an index.
Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans
Abstract
Light is considered the most potent synchronizer of the human circadian system and exerts many other non-image-forming effects, including those that affect brain function. These effects are mediated in part by intrinsically photosensitive retinal ganglion cells that express the photopigment melanopsin. The spectral sensitivity of melanopsin is greatest for blue light at approximately 480 nm. At present, there is little information on how the spectral composition of light to which people are exposed varies over the 24 h period and across seasons. Twenty-two subjects, aged 22+/-4 yrs (mean+/-SD) participated during the winter months (November-February), and 12 subjects aged 25+/-3 yrs participated during the summer months (April-August). Subjects wore Actiwatch-RGB monitors, as well as Actiwatch-L monitors, for seven consecutive days while living in England. These monitors measured activity and light exposure in the red, green, and blue spectral regions, in addition to broad-spectrum white light, with a 2 min resolution. Light exposure during the day was analyzed for the interval between 09:00 and 21:00 h. The time course of white-light exposure differed significantly between seasons (p = 0.0022), with light exposure increasing in the morning hours and declining in the afternoon hours, and with a more prominent decline in the winter. Overall light exposure was significantly higher in summer than winter (p = 0.0002). Seasonal differences in the relative contribution of blue-light exposure to overall light exposure were also observed (p = 0.0006), in particular during the evening hours. During the summer evenings (17:00-21:00 h), the relative contribution of blue light was significantly higher (p < 0.0001) (40.2+/-1.1%) than during winter evenings (26.6+/-0.9%). The present data show that in addition to overall light exposure, the spectral composition of light exposure varies over the day and with season.
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“In line with these results, findings from Swedish office workers indicate a higher exposure to light radiation of short wavelengths in summer compared to winter, autumn and spring.”
From Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness (2021) · cites this paper as [70]
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“Furthermore, seasonal differences in daily light exposure between summer and winter have been reported [70], showing an overall lower exposure time to short-wavelength light in winter (November–February) as compared to summer (April–August) in a student population from the UK.”
From Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness (2021) · cites this paper as [70]
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Cites
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ETHICS AND METHODS FOR BIOLOGICAL RHYTHM RESEARCH ON ANIMALS AND HUMAN BEINGS
Portaluppi, F., Smolensky, M. H., & Touitou, Y. (2010) · Chronobiology International · doi:10.3109/07420528.2010.516381 · Cited by 1,125
Entrainment of the Human Circadian Clock to the Natural Light-Dark Cycle
Wright, K. P., McHill, A. W., Birks, B. R., Griffin, B. R., Rusterholz, T., & Chinoy, E. D. (2013) · Current Biology · doi:10.1016/j.cub.2013.06.039 · Cited by 783
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Self-citationCircadian Entrainment to the Natural Light-Dark Cycle across Seasons and the Weekend
Stothard, E. R., McHill, A. W., Depner, C. M., Birks, B. R., Moehlman, T. M., Ritchie, H. K., Guzzetti, J. R., Chinoy, E. D., LeBourgeois, M. K., Axelsson, J., et al. (2017) · Current Biology · doi:10.1016/j.cub.2016.12.041 · Cited by 303
Metadata
- Authors
- Thorne, H. C., Jones, K. H., Peters, S. P., Archer, S. N., & Dijk, D.-J.
- Affiliations
- University of Surrey (GB)
- Corresponding author
- Thorne, Helen C.
- Venue
- Chronobiology International
- Publisher
- Informa UK Limited
- Published
- 2009-01
- Volume
- 26
- Issue
- 5
- Pages
- 854-866
- ISSN
- 0742-0528 (ISSN-L)
- 1525-6073
- OpenAlex
- W2161404195
- Cited by
- 153
- References
- 45
- Citations by year
- 2026: 9 · 2025: 17 · 2024: 8 · 2023: 18 · 2022: 11 · 2021: 14 · 2020: 9 · 2019: 8 · 2018: 7 · 2017: 9 · 2016: 7 · 2015: 6 · 2014: 7 · 2013: 7 · 2012: 7
- FWCI
- 2.39
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Chronobiology International (publishedVersion)
- PubMed (publishedVersion)
- Surrey Research Insight Open Access (The University of Surrey) (submittedVersion)
- Funders
- Wellcome Trust
- Biotechnology and Biological Sciences Research Council
- Topics
- Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
- Physical Sciences › Environmental Science › Global and Planetary Change › Impact of Light on Environment and Health
- Life Sciences › Agricultural and Biological Sciences › Plant Science › Light effects on plants
- Keywords
- spectral composition of light, circadian rhythm, seasonal variation, blue light exposure, melanopsin, intrinsically photosensitive retinal ganglion cells, white light exposure, diurnal variation, evening light exposure
- MeSH terms
- Melanopsin, Adolescent, Adult, Circadian Rhythm, Climate, Female, Humans, Light, Male, Photochemistry, Research Design, Seasons, Sleep, Genetic Variation, Rod Opsins
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