The Nuance
Is Blue Light Really What’s Keeping You Awake?
It’s a convenient scapegoat, but there are other reasons that devices mess with your sleep
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Every week, the Nuance will go beyond the basics, offering a deep and researched look at the latest science and expert insights on a buzzed-about health topic.
Light plays a crucial role in regulating many of the body’s internal processes, including the circadian rhythms that govern sleep. Among night-shift workers, fatigue, insomnia, and performance impairments are so common that experts have coined the term “shift work disorder” to encapsulate the symptoms. Research has even linked some forms of cancer and heart disease to the internal disruptions that stem from ignoring the sun’s sleep-wake cues.
So it makes sense that holding a light-emitting device a few inches from your eyeballs would disrupt your sleep. And there’s some evidence to support this theory. Studies have shown that exposing a person to blue light — a type of short wavelength light commonly emitted by digital devices — can suppress the body’s release of melatonin, a hormone that helps regulate sleep. And research from Harvard Medical School has found that people who read traditional paper books fall asleep faster and feel more alert the next morning than those who go to bed with an e-reader.
Experts say blue light isn’t the only thing — or even the primary thing — linking your bedtime device use to sleep issues.
A blue light–blocking filter or one of those light-mellowing programs built into most smartphones should remove any sleep risks, right? That would be a convenient solution (especially for device makers and app sellers who want you to stay glued to your screens), experts say blue light isn’t the only thing — or even the primary thing — linking your bedtime device use to sleep issues.
“Based on my research and that of others, we have consistently found that the blue-enriched light from screens tested in a single night in a sleep laboratory does not affect sleep,” says Michael Gradisar, a sleep researcher and professor of psychology at Flinders University in Australia. While…
