Having trouble to doze off? It’s tempting to blame the phone for the endless newsfeed. However, the notion that it’s the blue light emitted by smartphones that’s disrupting sleep isn’t fairly right.
While blue or short-wavelength light such as – daylight or that emitted by tech – does affect our circadian rhythm, things are less clear-cut than we often think, reports The Guardian.
“Sleep is a complex process,” says Stuart Peirson, professor of circadian neuroscience at the University of Oxford.
He explains that while the receptors in our eyes that tell our brain when it’s time to be awake are prompted by cells that absorb blue light, they’re also triggered by those that absorb longer wavelengths of light (such as red). This means it’s not the colour of the glow that’s the problem, it’s the brightness and length of time we’re exposed to it – and the screens of our phones are pretty dim.
Daylight is 1,000 times brighter than the average light emitted by a phone. Room lighting is, on average, 10 times brighter. (This is why turning off the big light as you wind down in the evening can help you feel sleepier.)
“Technically, blue light from smartphones can affect sleep,” says Peirson. “But these effects are small unless you are using your phone for hours with a bright screen and already have sleep problems.”
In lab studies at Harvard University, even around four hours of light exposure from an e-reader at full strength had only a relatively small effect: a 10-minute delay in sleep onset. In fact, your sleep is more likely to be affected by the kinds of content you’re consuming.
If you think light is impacting your sleep, Peirson says you don’t need to spend money on special “blue-light blocking” glasses. Instead, he recommends decreasing screen time and turning down the phone’s brightness.
Bd-pratidin English/ Fariha Nowshin Chinika
