Room light before bedtime may impact sleep quality, blood pressure and diabetes risk

New study shows indoor lighting has profound suppressive effect on the hormone melatonin

2011-01-14

(Press-News.org) Chevy Chase, MD—According to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM), exposure to electrical light between dusk and bedtime strongly suppresses melatonin levels and may impact physiologic processes regulated by melatonin signaling, such as sleepiness, thermoregulation, blood pressure and glucose homeostasis.

Melatonin is a hormone produced at night by the pineal gland in the brain. In addition to its role in regulating the sleep-wake cycle, melatonin has been shown to lower blood pressure and body temperature and has also been explored as a treatment option for insomnia, hypertension and cancer. In modern society, people are routinely exposed to electrical lighting during evening hours to partake in work, recreational and social activities. This study sought to understand whether exposure to room light in the late evening may inhibit melatonin production.

"On a daily basis, millions of people choose to keep the lights on prior to bedtime and during the usual hours of sleep," said Joshua Gooley, PhD, of Brigham and Women's Hospital and Harvard Medical School in Boston, Mass. and lead author of the study. "Our study shows that this exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could, in turn, have effects on sleep quality and the body's ability to regulate body temperature, blood pressure and glucose levels."

In this study, researchers evaluated 116 healthy volunteers aged 18-30 years who were exposed to room light or dim light in the eight hours preceding bedtime for five consecutive days. An intravenous catheter was inserted into the forearms of study participants for continuous collection of blood plasma every 30-60 minutes for melatonin measurements. Results showed exposure to room light before bedtime shortened melatonin duration by about 90 minutes when compared to dim light exposure. Furthermore, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50 percent.

"Given that chronic light suppression of melatonin has been hypothesized to increase relative risk for some types of cancer and that melatonin receptor genes have been linked to type 2 diabetes, our findings could have important health implications for shift workers who are exposed to indoor light at night over the course of many years," said Gooley. "Further research is still needed to both substantiate melatonin suppression as a significant risk factor for breast cancer and determine the mechanisms by which melatonin regulates glucose metabolism."

INFORMATION: Other researchers working on the study include: Kyle Chamberlain of the University of Surrey in the United Kingdom; and Kurt Smith, Sat Bir Khalsa, Shantha Rajaratnam, Eliza Van Reen, Jamie Zeitzer, Charles Czeisler and Steven Lockley of Brigham and Women's Hospital and Harvard Medical School in Boston, Mass.

The article, "Exposure to room light prior to bedtime suppresses melatonin onset and shortens melatonin duration in humans," appears in the March 2011 issue of JCEM.

Founded in 1916, The Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at www.endo-society.org.

ELSE PRESS RELEASES FROM THIS DATE:

Women with polycystic ovary syndrome may be more vulnerable to BPA

2011-01-14

Chevy Chase, MD—A recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM), found higher Bisphenol A (BPA) levels in women with polycystic ovary syndrome (PCOS) compared to controls. Furthermore, researchers found a statistically significant positive association between male sex hormones and BPA in these women suggesting a potential role of BPA in ovarian dysfunction. BPA is a very common industrial compound used in food and drink packaging, plastic consumer products and dental materials. PCOS is the most ...

Race plays role in weight-related counseling among obese patients

2011-01-14

When it comes to advising obese patients, blacks receive less weight reduction and exercise counseling from physicians than their white counterparts. This is according to a recent study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health who examined the impact of patient and doctor race concordance on weight-related counseling. The results are featured in the January 2011 online issue of Obesity. "Contrary to our expectations, we did not observe a positive association between patient-physician race concordance and weight-related counseling," ...

When continents formed

2011-01-14

The continental crust is the principal record of conditions on the Earth for the last 4.4 billion years. Its formation modified the composition of the mantle and the atmosphere, it supports life, and it remains a sink for carbon dioxide through weathering and erosion. The continental crust therefore has had a key role in the evolution of the Earth, and yet the timing of its generation remains the topic of considerable debate. It is widely believed that the juvenile continental crust has grown from the depleted upper mantle. One common way to assess when new crust was ...

Researchers can predict your video game aptitude by imaging your brain

2011-01-14

CHAMPAIGN, Ill. — Researchers report that they can predict "with unprecedented accuracy" how well you will do on a complex task such as a strategic video game simply by analyzing activity in a specific region of your brain. The findings, published in the online journal PLoS ONE, offer detailed insights into the brain structures that facilitate learning, and may lead to the development of training strategies tailored to individual strengths and weaknesses. The new approach used established brain imaging techniques in a new way. Instead of measuring how brain activity ...

BSE pathogens can be transmitted by air

2011-01-14

Airborne prions are also infectious and can induce mad cow disease or Creutzfeldt-Jakob disorder. This is the surprising conclusion of researchers at the University of Zurich, the University Hospital Zurich and the University of Tübingen. They recommend precautionary measures for scientific labs, slaughterhouses and animal feed plants. The prion is the infectious agent that caused the epidemic of mad cow disease, also termed bovine spongiform encephalopathy (BSE), and claimed the life of over 280,000 cows in the past decades. Transmission of BSE to humans, e.g. by ...

New predator 'dawn runner' discovered in early dinosaur graveyard

2011-01-14

A team of paleontologists and geologists from Argentina and the United States on Jan. 13 announced the discovery of a lanky dinosaur that roamed South America in search of prey as the age of dinosaurs began, approximately 230 million years ago. Sporting a long neck and tail and weighing only 10 to 15 pounds, the new dinosaur has been named Eodromaeus, the "dawn runner." "It really is the earliest look we have at the long line of meat eaters that would ultimately culminate in Tyrannosaurus rex near the end of the dinosaur era," said Paul Sereno, University of Chicago ...

Academics urge universities to change culture to value teaching as highly as research

2011-01-14

Irvine, Calif. — The reward systems at universities heavily favor science, math and engineering research at the expense of teaching, which can and must change. That's the conclusion of UC Irvine biology professor Diane K. O'Dowd and research professors at Harvard University, Yale University, the Massachusetts Institute of Technology, and elsewhere. Writing in the Jan. 14 issue of Science magazine, the authors note that professors have two responsibilities: to generate new knowledge and to educate students. But, they maintain, "although education and lifelong learning ...

Cardiff scientists make hydrocarbon breakthrough using gold catalyst

2011-01-14

Researchers from Cardiff University are opening up a new way of using hydrocarbon feedstocks to make a range of valuable products. Hydrocarbons are an extremely important energy resource but, although widely available from fossil fuels, are extremely difficult to activate and require very high temperatures in current industrial processes. For the first time, the Cardiff study has shown that the primary carbon-hydrogen bonds in toluene, a hydrocarbon widely used as an industrial material, can be activated selectively at low temperatures. Professor Graham Hutchings ...

Cancer survivors likely to experience pain at some point in care: U-M study shows

2011-01-14

ANN ARBOR, Mich. – Surviving cancer may also mean surviving pain, according to a study by the University of Michigan Health System showing 20 percent of cancer survivors at least two years post diagnosis have current cancer-related chronic pain. The study, published online ahead of print in the American Cancer Society's journal Cancer, gives new insight on issues in cancer survivorship among the growing number of U.S. cancer survivors. More than 40 percent of patients surveyed had experienced pain since their diagnosis, and the pain experience was worse for blacks ...

Popular sleep medicine puts older adults at risk for falls, cognitive impairment

2011-01-14

Adults who take one of the world's most commonly prescribed sleep medications are significantly more at risk for nighttime falls and potential injury, according to a new study by the University of Colorado at Boulder. The study, which involved 25 healthy adults, showed 58 percent of the older adults and 27 percent of the young adults who took a hypnotic, sleep-inducing drug called zolpidem showed a significant loss of balance when awakened two hours after sleep. The findings are important because falls are the leading cause of injury in older adults, and 30 percent of ...

Labor market immigrants moving to Germany are less likely to make their first choice of residence in regions where xenophobic attitudes, measured by right-wing party support and xenophobic violence, a

Lots of screentime in toddlers is linked with worse language skills, but educational content and screen use accompanied by adults might help, per study across 19 Latin American countries

Room light before bedtime may impact sleep quality, blood pressure and diabetes risk

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: