Light at Night
Light at night is a growing concern. You can make appropriate night lighting choices to aid sleep and promote health and safety!
What the package can tell you...
What light is appropriate at night?
- Look for fluorescent or compact fluorescent bulbs (CL) with warm "color temperature" - approximately 2700 Kelvin
- For precise light measurement, purchase a light meter
- A light meter measures lux
- It is best to have 51 lux or less on the face of a sleeping person
- Always purchase lighting products from a reputable manufacturer
People are sensitive to light cycles that affect sleep/wake cycles (circadian rhythms)
These conditions are healthy and existed before modern electric lighting.
These modern conditions may cause problems.
Remember: It is not possible or advised to eliminate all light at night. Some electric light should be available for safe nighttime movement (such as trips from bedroom to bathroom). Low light levels using incandescent or 2700 Kelvin fluorescent lights are recommended as "night lights". Lights from electronic screens can impact sleep. Be sure to turn off televisions and electronic devices with screens in bedrooms. Scientists are currently studying this modern problem.
When can light at night be a problem?
Light at night may contribute to...
- Sleep disturbances or disorders
- Health issues:
- Fatigue, hormone problems, coronary diseases, endocrine and immune system problems, reproduction difficulties and cancers
- Human errors and accidents
Light at night affects
- Young children and adolescents
- Older adults
- Shift workers
- People who stay in hospitals, care facilities, correctional facilities, and other places that are open 24 hours
Light at night recommendations for home interiors and other buildings where people sleep:
- Close window coverings
- Use lower light levels at night than in day time (less than 51 lux)
- Choose bulbs with warm color temperature
- Turn off televisions, computers, tablets, cellphones, and other devices with illuminated "blue" screens
American Medical Association. Council on Science and Public Health. (2012). Light pollution: Adverse health effects of nighttime lighting (CSAPH Report 4-A-12).
Boivin, D.B., & James, F.O. (2002, December). Circadian adaptation to night-shift work by judicious light and darkness exposure. Journal of Biological Rhythms, 17(6), 556-567.
Boyce, P.R. (2010). Review: The impact of light in buildings on human health. Indoor and Built Environment, 19(8), 8-20.
Illuminating Engineering Society of North America. IES Light and Human Health Committee. (2008). Light and human health: An overview of the impact of optical radiation on visual, circadian, neuroendocrine, and neurobehavioral responses (Research Report IES TM-18-08). New York, NY: IESNA.
Illuminating Engineering Society of North America. IESNA Lighting for the Aged and Partially Sighted Committee. (2007). Recommended practice for lighting and the visual environment for senior living (Research Report ANSI/IESNA RP-28-07). New York, NY: IESNA.
Martin, S.K., & Eastman, C.I. (1998). Medium-intensity light produces circadian rhythm adaptation to simulated night-shift work. Sleep, 21(2), 154-165.
Rea, M.S. (2002). Light - Much more than vision. Paper presented at the 5th International Lighting Research Symposium, Palo Alto, CA.
U.S. Department fo Energy. (2010, January). Light at night and human health [Fact sheet].
Paulette Hebert, Ph.D
Design, Housing & Merchandising
Mihyun Kang, Ph.D.
Design, Housing & Merchandising
Gina Peek, Ph.D.
Extension Housing & Consumer Specialist
Oklahoma Cooperative Extension service
Oklahoma Cooperative Extension SErvice
Marinana Figueriro, Ph.D,
Rensselaer Polytechnic Institute
OKlahoma Home and Community Education, Inc.