Jefferson And Brigham And Women’s Researchers Find Blue Light Important For Setting Biological Clock
Researchers from Brigham and Women's Hospital (BWH) in Boston and Jefferson Medical College have found that the body's natural biological clock is more sensitive to shorter wavelength blue light than it is to the longer wavelength green light, which is needed to see.
The discovery proves what scientists have suspected over the last decade: a second, non-visual photoreceptor system drives the body's internal clock, which sets sleep patterns and other physiological and behavioral functions.
"This discovery will have an immediate impact on the therapeutic use of light for treating winter depression and circadian disorders," says George Brainard, Ph.D., professor of neurology at Jefferson Medical College of Thomas Jefferson University in Philadelphia. "Some makers of light therapy equipment are developing prototypes with enhanced blue light stimuli."
"In the long range, we think this will shape all artificial lighting, whether it's used for therapeutic purposes, or for normal illumination of workplaces, hospitals or homes – this is where the impact will be," he says. "Broad changes in general architectural lighting may take years, but the groundwork has been laid."
In theory, he says, "If a clinician wants to use light therapeutically, the blue wavelengths may be more effective. If you wanted built-in illumination that would enhance circadian regulation, you might want this wavelength region emphasized. It is interesting that natural daylight – the blue sky – is rich in this part of the spectrum."