Feeling Blue

Researchers have known for a while that blue light from screens discourages sleep. Now researchers from the University of Manchester in England have a identified a specific shade that has an impact on sleep — cyan.

Additive color blue lightExposure to higher levels of cyan blue light, a color between green and blue, drops the production of the sleep hormone melatonin, according to a June 22 article by the BBC.

Cyan can be used to create other colors, such as certain shades of green, the article noted. But researchers say the same colors can be created without cyan.

The study, published in the May 18 issue of the journal Sleep, determined the difference the color made by screening a film — with colors adapted to include and exclude cyan — and measuring melatonin in the viewers’ saliva.

“This outcome is exciting because it tells us that regulating exposure to cyan light alone, without changing color, can influence how sleepy we feel,” said researcher Rob Lucas, professor of neuroscience, in the BBC article.