Lighting Research Center

Advancing the effective use of light for society and the environment

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Light & Health

Light and Shift Work

In the U.S. and Europe, 1520% 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.

Healthy Lighting for Shift Work

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

  • The National Institute for Occupational Safety and Health (NIOSH), 1R01OH010668

  • Related publication:
  • 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.

 Red Light Delivered During Sleep to Reduce Sleep Inertia pdf logo

Red Light Improves Nighttime Alertness and Performance  pdf logo

Circadian Lighting for U.S. Navy Submarines pdf logo

Shift Work and Circadian Disruption

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 pdf logo

  • Office of Naval Research, N00014-11-1-0572
  • Swedish Energy Agency through Lund University
    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 pdf logo

Bridging Animal Models to Human Health Outcomes pdf logo

New Insight on Ways Circadian Disruption Affects Human Health pdf logo

Light as a Controlling Stimulus for Behavior Cancer Research: Bridging Human Exposures to Animal Models for Parametric Investigations 

Further reading:

Media Coverage

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.








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