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Troy, N.Y. -  7/11/2011

"Best of Sleep Medicine 2011" Textbook Includes LRC Field Study Results on Impact of Light on Teens' Sleeping Habits

Paper Selected From Thousands of Journal Articles Published in 2010

Dr. Mariana G. Figueiro and middle-school studentResearch led by Rensselaer Polytechnic Institute Associate Professor Mariana Figueiro on the impact of light on teenagers’ sleeping habits was selected for publication in Best of Sleep Medicine 2011. The textbook is designed to keep sleep clinicians, researchers, and technologists informed of the latest science and technology advances in the growing field of sleep medicine.

According to Editor Dr. Teofilo Lee-Chiong of National Jewish Health, Best of Sleep Medicine 2011 covers the entire spectrum of adult and pediatric sleep sciences and is designed to represent some of the finest scientific literature on sleep medicine published in 2010. The articles are selected from among thousands of journal articles in medicine, neurology, psychiatry, and surgery periodicals. The book contains concise summaries of the notable works accompanied by commentaries written by major international authorities on sleep medicine. 

Figueiro, Light and Health Program director at the LRC, led a series of field studies examining the impact of light on teenagers’ sleeping habits. The paper selected for publication in Best of Sleep Medicine 2011 details results from one of those studies where the LRC research team found that 11 8th grade students who wore special glasses to prevent short-wavelength (blue) morning light from reaching their eyes experienced a 30-minute delay in the onset of melatonin, the hormone that indicates to the body when it’s nighttime, according to Figueiro. The human circadian system is maximally sensitive to blue light, therefore removal of morning blue light can reduce synchronization of the sleep/wake cycle to the 24-hour solar day.

The details of the study were summarized in the paper “Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students,” by Figueiro and LRC Director Mark Rea, and published by the journal Neuroendocrinology Letters 2010:31(1).

The series of field studies examined not only the impact of removing morning blue light, but also the seasonal impact and the increased evening light exposure during the spring months on teens’ melatonin onset and sleep times.

“The field studies supported the research team’s general hypothesis that the entire 24-hour pattern of light/dark exposure influences synchronization of the body’s circadian clock with the solar day and thus influences teenagers’ sleep/wake cycles,” said Figueiro. “As a general rule, teenagers should increase morning daylight exposure year round and decrease evening daylight exposure in the spring to help ensure they will get sufficient sleep before going to school.” 

In the series of studies, each subject wore a Daysimeter, a small, head-mounted device developed by the LRC to measure an individual’s exposure to daily “circadian light,” as well as rest and activity patterns. The definition of circadian light is based upon the potential for light to suppress melatonin synthesis at night, as opposed to measuring light in terms of how it stimulates the visual system.

The studies, sponsored by the U.S. Green Building Council (USGBC) and, in part, by a grant from a Trans-National Institutes of Health Genes, Environment and Health Initiative (NIH-GEI), were able to relate field measurements of circadian light exposures to a well-established circadian marker—evening melatonin levels.

To read more about LRC field studies, visit

Best of Sleep Medicine 2011 is available at

About the Lighting Research Center
The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is the world's leading center for lighting research and education. Established in 1988 by the New York State Energy Research and Development Authority (NYSERDA), the LRC conducts research in light and human health, transportation lighting and safety, solid-state lighting, energy efficiency, and plant health. LRC lighting scientists with multidisciplinary expertise in research, technology, design, and human factors, collaborate with a global network of leading manufacturers and government agencies, developing innovative lighting solutions for projects that range from the Boeing 787 Dreamliner to U.S. Navy submarines to hospital neonatal intensive-care units. In 1990, the LRC became the first university research center to offer graduate degrees in lighting and today, offers a M.S. in lighting and a Ph.D. to educate future leaders in lighting. Learn more at

About Rensselaer Polytechnic Institute
Founded in 1824, Rensselaer Polytechnic Institute is America's first technological research university. Rensselaer encompasses five schools, 32 research centers, more than 145 academic programs, and a dynamic community made up of more than 7,900 students and more than 100,000 living alumni. Rensselaer faculty and alumni include more than 145 National Academy members, six members of the National Inventors Hall of Fame, six National Medal of Technology winners, five National Medal of Science winners, and a Nobel Prize winner in Physics. With nearly 200 years of experience advancing scientific and technological knowledge, Rensselaer remains focused on addressing global challenges with a spirit of ingenuity and collaboration.