Circadian disruption and increase of oxidative stress in male and female volunteers after bright light exposure before bed time
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.
Male and female healthy volunteers aged 20–30 were exposed to 4 hours of bright light before bed for 3 and 4 days.
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.
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.
KeywordsCircadian disruption Bright light Before bedtime Cortisol Oxidative stress Male and Female
Unable to display preview. Download preview PDF.
- 1.DiTacchio, L., DiTacchio, K. A. & Panda, S. Relevance of circadian rhythm in cancer. Energy Balance and Cancer 1–19 (2015).Google Scholar
- 2.Albers, S. & Duriscoe, D. Modeling light pollution from population data and implications for National Park Service lands. George Wright Forum 18, 56–68 (2001).Google Scholar
- 4.Stevens, R. G. et al. Considerations of circadian impact for defining ‘shift work’ in cancer studies: IARC Working Group Report. Occup Environ Med 2009, 053512 (2010).Google Scholar
- 13.Kim, Y. J., Lee, E., Lee, H. S., Kim, M. & Park, M. S. High prevalence of breast cancer in light polluted areas in urban and rural regions of South Korea: An ecologic study on the treatment prevalence of female cancers based on National Health Insurance data. Chronobiol Int 32, 657–667 (2015).CrossRefGoogle Scholar
- 18.Corbella, O. & Yannas, S. Environmental study of two shopping malls in Rio de Janeiro. Eco-friendly 98, 483–486 (2014).Google Scholar
- 21.Kim, K. Y., Lee, E., Kim, Y. J. & Kim, J. The association between artificial light at night and prostate cancer in Gwangju City and South Jeolla Province of South Korea. Chronobio lInt 1–9 (2016).Google Scholar
- 32.Santiago, L. B., Jorge, S. M. & Moreira, A. C. Longitudinal evaluation of the development of salivary cortisol circadian rhythm in infancy. J Clin Endocrinol Metab 44, 157–161 (1996).Google Scholar
- 34.Schulz, P., Kirschbaum, C., Prüßner, J. & Hellhammer, D. Increased free cortisol secretion after awakening in chronically stressed individuals due to work overload. Stress Health 14, 91–97 (1998).Google Scholar