Those mesmerizing blue and orange hues in the sky at the start and end of a sunny day might have an essential role in setting humans' internal clocks. In new research from the University of Washington in Seattle, a novel LED light that emits alternating wavelengths of orange and blue outpaced two other light devices in advancing melatonin levels in a small group of study participants. Published in the Journal of Biological Rhythms , the finding appears to establish a new benchmark in humans' ability to influence their circadian rhythms, and reflects an effective new approach to counteract seasonal affective disorder (SAD).
A raft of health and mood problems have been attributed to out-of-sync circadian rhythms. Such asynchrony is encouraged by seasonal changes, a lack of exposure to natural light , graveyard-shift jobs and flights across multiple time zones . "Our internal clock tells us how our body's supposed to act during different times of day, but the clock has to be set, and if our brain is not synced to the time of day, then it's not going to work right," said Jay Neitz, a co-author on the paper and a professor of ophthalmology at the UW School of Medicine.
Circadian rhythms are trained and reset every day by the 24-hour solar cycles of light and dark, which stimulate circuits in the eyes that communicate to the brain. With that information, the brain produces melatonin, a hormone that helps organisms become sleepy in sync with the solar night. People who spend many da.