Light, sleep, melatonin, and cancer

Blue light has a dark side, an article from Harvard Medical School, and a 12-min video clip of Russel J. Reiter, M.D. PhD of University of Texas talking about Melatonin’s role in Cancer are both worth your time, especially if you’re involved in the design of healthcare facilities.

The Harvard article concludes that

“Light at night is bad for your health, and exposure to blue light emitted by electronics and energy-efficient lightbulbs may be especially so.”   

This phenomenon is becoming well-documented; even the American Medical Association issued a policy in 2012 recognizing the adverse health effects of nighttime lighting (though they don’t call out blue light specifically).  The health effects of light’s color have also been studied in health care design.

Dr. Reiter, an expert in melatonin production, is a convincing speaker.  His main points are that the pineal gland produces melatonin only at night, melatonin is a known cancer-inhibitor, light at night (even turning a light on for one second) prevents the pineal gland from producing melatonin. Only a very narrow bandwidth of light inhibits melatonin production – the blue range (460 – 480 nanometer light).  The yellow, orange, or red range of light is least disruptive at night.

I’d be very interested to learn of other experiences, articles, reports, or findings on this subject, especially as it touches the design of healthcare environments.  Thanks, Erich, for the Harvard article.