All living things — from animals and plants down to cells — carry inside them a clock set to the most basic cycle on Earth: night and day.
Scientists believe that this clock, called circadian rhythm, dates to the very beginning of life on Earth, some 3.5 billion years ago. It helps us stay awake and active when the sun is out, and rest during the night so cells can carry out basic maintenance and the brain can record memories.
What’s more, we've messed with our internal clocks by adjusting for daylight saving time. No wonder scientists around the world have been looking for a fix.
One team of engineers at GE Lighting recently came up with an “intelligent” LED called CbyGE designed to help users wake up in the morning and fall asleep at night. “We’ve built an LED light that changes colors and helps the body conform better to its circadian rhythm,” says Carmen Pastore, marketing leader for GE Lighting.
GE scientists invented the first visible LED in the 1960s and modern LED technology gave the team access to an “infinite palette” of colors.
But it focused on two: blue and yellow. That’s because those colors stimulate receptors in the eye’s retina that control the level of the sleep-inducing hormone melatonin in the body.
Yellow and orange hues, which humans got used to by watching millions of sunsets before going to sleep, stimulate melatonin production, while bright blue morning light tells the body to reduce the hormone’s level and get ready for a day’s work. “This is 3 billion years of evolution we are dealing with,” Pastore says. “Our LED is helping the body adjust, rather than waiting for the body to catch up to technological progress.”
Pastore says that effect of light is especially strong at night. “You can feel the hard punch of the blue light when you turn on your tablet in the middle of the night,” says Pastore. “Good luck falling asleep again. But a nice yellow glow will help you change a diaper and you and your toddler will go straight back to sleep.”
Pastore says the new LED contains a chip that could change its color from banana yellow to blueberry blue. But there is no need for such extremes. Instead, his team designed the light to fall within a range of subtle hues that can do the trick without being disruptive.
Customers can control the light with an app from their smartphones and tablets over Bluetooth.
Says Pastore: “It sounds high-tech, but we are really getting back to nature.”