Light and Shift Work
In the U.S. and Europe, 15–20% of all full-time personnel are employed outside of regular working hours, with over 7 million Americans following shift-work schedules. Shift work, especially when it involves rotating and overnight shifts, is associated with increased risks for developing cancer and other diseases. Research in this area has focused on circadian disruption and exposure to light at night (LAN), both of which are involved in melatonin suppression and its associated cancer risks. Scientists at the LRC have been exploring the role of light in these two avenues of research, and investigating how light can be used to improve performance and facilitate healthier outcomes for shift workers.
Some recent LRC research projects regarding the effects of light on shift workers are highlighted below.
Laboratory studies conducted at the LRC have demonstrated that short-wavelength (blue) and long-wavelength (red) light increases alertness and performance at night, although only blue light significantly suppresses melatonin, suggesting that melatonin suppression is not required to promote nighttime alertness and improve performance.
The National Institute for Occupational Safety and Health (NIOSH) has recently funded a four-year project that will provide LRC researchers with the opportunity to field test these laboratory results in a healthcare setting. This research, which employs a novel lighting intervention utilizing red light, is designed to determine whether healthcare workers' alertness and performance can be improved without disrupting their natural melatonin production. If shown to be effective in reducing errors and improving quality of life, this intervention will provide a non-pharmacological treatment to help healthcare workers cope with irregular nighttime work schedules without disrupting their circadian rhythms.
Summaries of select LRC research projects are linked below in PDF format.
Lighting Interventions to Reduce Circadian Disruption in Rotating Shift Workers
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Sponsor:
- The National Institute for Occupational Safety and Health (NIOSH), 1R01OH010668
- Hunter CM, Figueiro MG. 2016. Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature. Biological Research for Nursing, in press.
Related publication:
Red Light Delivered During Sleep to Reduce Sleep Inertia 
Red Light Improves Nighttime Alertness and Performance
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Sponsor:
- Office of Naval Research
- Figueiro MG, Pedler D. 2020. Red light: A novel, non-pharmacological intervention to promote alertness in shift workers. Journal of Safety Research74:169-77.
- Figueiro MG, Sahin L, Wood B, Plitnick B. 2016. Light at night and measures of alertness and performance: Implications for shift workers. Biological Research for Nursing. 17:1-8.
- Plitnick B, Figueiro MG, Wood B, Rea MS. 2010. The effects of red and blue light on alertness and mood at night. Lighting Research and Technology. 42(4):449-458.
- Figueiro MG, Bierman A, Plitnick B, Rea MS. 2009. Preliminary evidence that both blue and red light can induce alertness at night. BMC Neuroscience. 10(105).
- Figueiro MG, Bullough JD, Bierman A, Fay CR, Rea MS. 2007. On light as an alerting stimulus at night. Acta Neurobiologiae Experimentalis. 67(2):171-178.
Related publications:
Circadian Lighting for U.S. Navy Submarines
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Sponsors:
- Commander of Submarine Forces
- Navy Bureau of Medicine and Surgery
- Office of Naval Research
- Lighting provided by GE
- Young CR, Jones GE, Figueiro MG, Soutière SE, Keller MW, Richardson AM, Lehmann BJ, Rea MS. 2015. At-sea trial of 24-h-based submarine watchstanding schedules with high and low correlated color temperature light sources. Journal of Biological Rhythms. 30(2):144-154.
- Crepeau LJ, Bullough JD, Figueiro MG, Porter S, Rea MS. 2006. Lighting as a circadian rhythm-entraining and alertness-enhancing stimulus in the submarine environment. Undersea HSI Symposium: Research, Acquisition, and the Warrior. Mystic, CT. June 6-8.
Related Publications:
Night shift work, especially prevalent among nurses and other healthcare workers, requires inverting the activity-rest cycle. As a result, shift workers are more likely to experience sleepiness and insomnia, along with decreased productivity, impaired safety, diminished quality of life, and adverse health effects. Light can help shift workers to stay awake, in part due to suppression of melatonin, but melatonin suppression and the resulting circadian disruption has been linked to increased risk for metabolic syndrome, diabetes, cardiovascular disease, and certain cancers.
Summaries of select LRC research projects are linked below in PDF format.
Mouse Glucose Tolerance and Light on Shift Work Schedules
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Sponsor:
- Office of Naval Research, N00014-11-1-0572
- Swedish Energy Agency through Lund University
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Related Publication:
- Figueiro MG, Radetsky L, Plitnick B, Rea MS. 2017. Glucose tolerance in mice exposed to light-dark stimulus patterns mirroring dayshift and rotating shift schedules. Scientific Reports. 7:40661.
Circadian Disruption: Comparing Humans to Mice
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Sponsors:
- Office of Naval Research
- DMX lighting control system donated by Philips Color Kinetics
- Rea MS, Figueiro MG. 2014. Quantifying light-dependent circadian disruption in humans and animal models. Chronobiology International Special Issue: Shift Work.10(2):107-113.
- Radetsky L, Rea MS, Bierman A, Figueiro MG. 2013. Circadian disruption: comparing humans with mice. Chronobiology International. 30(8):1066-71.
Related Publications:
Bridging Animal Models to Human Health Outcomes
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Sponsors:
- Swedish Energy Agency
- Office of Naval Research
- Rea MS, Figueiro MG. 2014. Quantifying light-dependent circadian disruption in humans and animal models. Chronobiology International Special Issue: Shift Work.10(2):107-113.
- Radetsky L, Rea MS, Bierman A, Figueiro MG. 2013. Circadian disruption: comparing humans with mice. Chronobiology International. 30(8):1066-71.
Related Publications:
New Insight on Ways Circadian Disruption Affects Human Health
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Sponsors:
- Centers for Disease Control and Prevention
- Trans-National Institutes of Health Genes, Environment and Health Initiative
- Rea MS, Bierman A, Figueiro MG, Bullough JD. 2008. A new approach to understanding the impact of circadian disruption on human health Journal of Circadian Rhythms. 6:7.
Related Publications:
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Sponsor:
- National Cancer Institute, Division of Cancer Control & Population Sciences
- Basic Biobehavioral and Psychological Sciences (BBPSB) Profile: Mariana Figueiro, PhD
Related Information:
Further reading:
- Lunn RM, Blask DE, Coogan AN, Figueiro MG, et al. 2017. Health consequences of electric lighting practices in the modern world: A report on the National Toxicology Program's workshop on shift work at night, artificial light at night, and circadian disruption.
Science of The Total Environment. 607-608:1073-1084. - Figueiro MG, White RD. 2013. Health consequences of shift work and implications for structural design. Journal of Perinatology. 33:S17-23.
- Stevens RG, Rea MS. 2001. Light in the built environment: potential role of circadian disruption in endocrine disruption and breast cancer. Cancer Causes and Control. 12(3):279-287.
LRC research on light and shift work has been featured in various media reports. For more featured media, visit our Newsroom Media Page.
Quantifying Circadian Light and Its Impact
Architectural Lighting - February 2017
Melanopic lux is the wrong metric for describing circadian-effective light. Here is a better alternative.
How to design circadian lighting - by top scientists
LUX Magazine - December 2016
US scientists have developed a special tool to help designers create lighting installations which affect the sleep-wake cycle.
Understanding Rotating Shift Workers' Health Risks
Occupational Health & Safety Magazine - November 2016
Until we know more, it is recommended that lighting in health care facilities should be designed to minimize acute melatonin suppression in night shift workers.
SIL Conference session to focus on the effects of lighting on health
LEDs Magazine - November 11, 2016
At the upcoming Strategies in Light conference (Feb. 28 - March 2, 2017; Anaheim, CA) the lead speaker in the Non-Visual Effects of Lighting session will be Dr. Mariana Figueiro, LRC Light and Health Program Director. In this essay, Dr. Figueiro highlights some of the topics she will discuss in her SIL conference presentation, including healthy lighting for adolescents, older adults, office workers, and night-shift workers.
Blue LEDs Light Up Your Brain
Scientific American - November 2016
LRC Light & Health Program Director Mariana Figueiro is featured in this article in the November issue of Scientific American exploring the science of why electronic screens keep you awake at night.
Designing with Circadian Stimulus
LD+A - October 2016
The Lighting Research Center proposes a metric for applying circadian light in the built environment.
Everything You Need to Know About How Light Affects Your Sleep
Van Winkle's - June 21, 2016
Until we evolve beyond a light-regulated circadian sleep/wake rhythm, we need to accept the relationship between light and sleep — and understand what we can do to help it along.
Mariana Figueiro Presents at NIH Workshop on Light at Night
News from the Lighting Research Center - March 14, 2016
Mariana Figueiro was invited to participate in the workshop "Shift Work at Night, Artificial Light at Night, and Circadian Disruption," held at the National Institute of Environmental Health Sciences. She presented an overview of light at night and its association with circadian disruption.
NIOSH-CDC Awards $2.2 Million for Light and Health Research to the Lighting Research Center
News from the Lighting Research Center - September 22, 2015
The National Institute for Occupational Safety and Health and the Centers for Disease Control and Prevention have awarded $2.2 million to Mariana Figueiro to support research that could benefit the more than 7 million Americans who work rotating or night shift schedules.
Night Shift Making You Sick? Red Light Could Help
WNYC News, New York Public Radio - May 27, 2014
News producer Paige Cowett of WNYC visited the Lighting Research Center to learn about our new study investigating the use of red light at night to facilitate healthier outcomes for shift workers.
View a list of publications, journal articles, and conference papers on light and health issues by Lighting Research Center scientists.