Circadian disruption and increase of oxidative stress in male and female volunteers after bright light exposure before bed time

Hyo Sun Lee, Eunil Lee, Joung Ho Moon, Yun Jeong Kim, Heon Jeong Lee

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Backgrounds: Circadian rhythms are patterns of behaviour, physiology, and metabolism that occur within a period of approximately 24 h. The higher risk of breast and prostate cancers among shift workers, as well as the general population, are reported to be associated with circadian rhythm disruption caused by exposure to light at night. We focused on the effects of bright light before bed comparing effects between men and women. Methods: Male and female healthy volunteers aged 20–30 were exposed to 4 hours of bright light before bed for 3 and 4 days. Results: We analyzed the shift of circadian rhythms of subjects based on cortisol secretion patterns in response to short periods of bright-light exposure at bedtime. We also found an increase of oxidative stress including MDA, 8-OHdG, and total antioxidants in both male and female volunteers. Conclusion: These results suggest that bright light exposure before sleep, often encounter in modern daily life, has a considerable influence on the human body. The chronic effects of light exposure before bed time such as the carcinogenic effects caused by circadian disruption and oxidative stress need further investigation.

Original languageEnglish
Pages (from-to)221-229
Number of pages9
JournalMolecular and Cellular Toxicology
Issue number2
Publication statusPublished - 2019 Apr 1

Bibliographical note

Funding Information:
And this study was supported in part by Korea University Grant, and also grants from Environmental Health Center for References Childhood Asthma, Ministry of Environment, Korea. This support is greatly appreciated.

Funding Information:
Acknowledgements This work was supported by the Korea Ministry of Environment (MOE) as The Environmental Health Action Program (2016001360007) and the National Research Foundation of Korea (NRF) grant funded by the Korea government (2016R1D1A1A02937060).

Publisher Copyright:
© 2019, The Korean Society of Toxicogenomics and Toxicoproteomics and Springer Nature B.V.


  • Before bedtime
  • Bright light
  • Circadian disruption
  • Cortisol
  • Male and Female
  • Oxidative stress

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Toxicology
  • Pharmacology, Toxicology and Pharmaceutics(all)
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis


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