Researchers Shed New Light on Blue’s Effect on Sleep


MANCHESTER, U.K.—Contrary to common belief, blue light may not be as disruptive to our sleep patterns as originally thought, according to University of Manchester scientists. According to the team, using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial to our health. Twilight is both dimmer and bluer than daylight, they say, and the body clock uses both of those features to determine the appropriate times to be asleep and awake.


The research, which was carried out on mice, used specially designed lighting that allowed the team to adjust color without changing brightness. That showed blue colors produced weaker effects on the mouse body clock than equally bright yellow colors.

The findings, say the team, have important implications for the design of lighting and visual displays intended to ensure healthy patterns of sleep and alertness. The study is published in Current Biology and funded by the Biotechnology and Biological Sciences Research Council.

The body clock uses a specialized light sensitive protein in the eye to measure brightness, called melanopsin, which is better at detecting shorter wavelength photons. This is why, say the team, researchers originally suggested blue light might have a stronger effect.

However, our perception of color comes from the retinal cone cells and the new research shows that the blue color signals they supply reduce the impact on light on the clock. Dr. Tim Brown, from The University of Manchester, said, “We show the common view that blue light has the strongest effect on the clock is misguided; in fact, the blue colors that are associated with twilight have a weaker effect than white or yellow light of equivalent brightness.



“Our findings suggest that using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial. Research has already provided evidence that aligning our body clocks with our social and work schedules can be good for our health. Using color appropriately could be a way to help us better achieve that.”