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Your Environment. Your Health.

Light and Its Impact on Circadian Disruption and Health: What We Know, What We Don't Know and What We Need to Know

The NIEHS Exposure Science and the Exposome Webinar Series
February 9, 2017


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The NIEHS Strategic Plan places a significant emphasis on transforming exposure science through the development of new approaches to exposure assessment, the definition and dissemination of the exposome concept, and the development and demonstration of the exposome as a tool for both epidemiological and mechanistic research. In order to achieve this goal, NIEHS launched the Exposure Science and the Exposome Webinar Series on April 4, 2014 to foster discussions on international efforts in advancing exposure science and the exposome concept as well as challenges and opportunities in incorporating this concept in environmental health research.


Environmental factors such as electric light at night (LAN) have been implicated as agents in endocrine disruption. It is hypothesized that LAN suppresses melatonin production by the pineal gland, which may shift rest/activities patterns, making them asynchronous with the solar day/night cycle. Circadian disruption has been linked to a series of maladies, including poor performance and higher stress, diabetes, obesity, and even cancer. Since light is the primary stimulus for controlling the timing of the biological clock, and therefore, melatonin production, it is important to quantify circadian light exposure throughout the 24-hour day and night. However, standard light meters are not designed to represent the spectral sensitivity of the circadian system, particularly the short wavelength portion of the visible spectrum, which has the largest impact on circadian functions. Moreover, since timing and duration of light exposure are so important to the circadian system, a satisfactory measure of circadian light exposure must also be able to measure when and for how long light is delivered to the human eye. This talk will provide an overview of light as it affects the circadian system, discuss tools to measure and specify circadian effective light as well as propose gaps in our knowledge of the health effects of light. Potential research studies to minimize these gaps will also be discussed.

Dr. Figueiro's full webinar


Mariana G. Figueiro, Ph.D., is Light and Health Program Director at the Lighting Research Center (LRC) and Professor at Rensselaer Polytechnic Institute. Dr. Figueiro holds a Ph.D. in multidisciplinary sciences and has over 20 years of experience in the study of human–light interactions. She currently serves as principal investigator (PI) on one grant from the National Institute of Occupational Safety and Health (NIOSH), one grant from the National Cancer Institute (NCI), and two grants from the National Institute on Aging (NIA) which are examining the effects of light on human health and wellbeing in a wide variety of populations including shift workers, persons with Alzheimer's disease and other dementias, and older adults. She is also a PI on a subaward from the US Army to develop and validate a circadian monitoring system. She also serves as PI on one grant from the Department of State and one grant from the General Services Administration, both investigating the impact of daytime light exposure on sleep and mood. Dr. Figueiro is also a PI on a grant from the Office of Naval Research investigating the impact of light on alertness and performance in laboratory and field settings. Dr. Figueiro is a fellow of the Illuminating Engineering Society (IES), has served as chair of the IES's committee on Light and Human Health, and has published more than 70 scientific and technical articles related to light and human health. She was invited to be a speaker at TEDMED on September 12, 2014 at the Kennedy Center in Washington, DC.
TedMed - Speaker: Mariana Figueiro

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