For a decade, we’ve been told our screens are wrecking our sleep. The real culprit is far bigger than the glow from your phone.
I have spent the last few weeks strapping on a pair of special orange safety goggles three hours before bed. They’re made of thick, uncomfortable plastic that casts the world in a dull amber glow, making it hard to see anything blue. But I don’t stop there.
I cover the windows with blackout curtains and switch off all my lamps, one by one. In their place, I exclusively light my apartment with candles. My sleep routine is deranged, but it’s for an experiment. I found out what happens when you banish blue light.
The world has grown increasingly panicked about this photochromatic fiend over the past 10 years. We’re told that our phones, TVs, computers, tablets, and LED light bulbs expose us to a perverse amount of blue light.
Supposedly, this ruins our sleep by disrupting the natural rhythms of daylight that influence our internal body clock. There’s science to back some of this up, but recent studies and analyses suggest that things are a lot more complicated.
In fact, chances are you’ve fallen for some serious misconceptions about this subject. Experts tell me it’s unlikely that light from your phone is ruining your sleep.
The research is mixed. Those features designed to dial down blue light on your phone at bedtime, for example, are probably doing very little to improve your sleep. But the lighting in modern life can really have a huge effect on your sleep. What would it take to make a change?
I wanted the truth. So, I called the experts and dove into the science.
And to see if I could spot the difference, I’ve plunged myself into the most extreme, blue-free evenings I could muster.
I landed on practical advice that you can use – no dorky tinted goggles required. It could be the secret to a good night’s sleep.
The blue screen of death?
The public freakout about blue light started with a 2014 study. Half of the 12 participants read on an iPad before bed. The rest read physical books. The iPad users took longer to fall asleep, felt groggier the next day, and produced less melatonin.
The researchers said the culprit was the glow emitted by the iPad’s LED screen, which produces disproportionately lighter at the upper, bluer end of the spectrum.
Under specific circumstances, blue-enriched light disrupts the daily circadian rhythm – our body’s natural pacemaker – that uses daylight to help determine when we start to feel tired. Subsequent research seemed to support the findings. Sounds simple, right? It’s not.
“This was an incredibly deceptive piece of work,” says Jamie Zeitzer, a professor of psychiatry and behavioural sciences at Stanford University, who studies the effect of light on the circadian system. The science wasn’t bad, he says, the problem is it brought people to bad conclusions.
It’s true that our screens are bluer. Modern screens and lightbulbs use LEDs, which cannot produce pure white light. Instead, they use blue LEDs and cover some of them with a chemical called yellow phosphor. The blue and yellow mix together, tricking your brain into seeing white, but extra blue always leaks out.
In most cases, scientists say the light from your phone just isn’t bright enough to have a big impact on your sleep (Credit: Hana Mendel)
Blue light can really affect your sleep.
Zeitzer says that’s mostly because you have a light-sensitive protein in your eyes called melanopsin, which plays a key role in your sleep system.
“And melanopsin is a blue-sensitive protein, which basically means that it is most sensitive to blue light,” he says. Melanopsin responds to other colors of light too; the effect of blue is just a bit stronger.
“But the amount of light emitted from our screens is really inconsequential,” says Zeitzer. Your life doesn’t match the conditions of many blue light studies.
“We bring someone into the laboratory, and they are exposed to very dim light all day long. And then they are given a bright light stimulus,” he says. Under those circumstances, blue light makes people go haywire, but it doesn’t reflect the typical human experience.
The amount of blue light emitted by the screens of phones, laptops, and tablets has also been shown to be tiny compared to the blue light we receive from the Sun – 24 hours’ worth of blue light from digital devices, when totted up, is less than one minute spent outdoors, according to one study.
Other studies have shown it’s not enough to affect hormone levels that control our sleep.
So why am I so tired all the time? Zeitzer and others told me there are lots of other ways that light, blue and otherwise, could be ruining my bedtime. If I really wanted to tackle the blue monster, it would take a serious lifestyle change.
Kind of blue
I was out for dinner as the Sun went down on day one of my experiment. Around 20:30, I said I needed to head home. It was time to hide from the light. Based on the advice I was getting from sleep specialists, my extreme bedtime prepping started long before I got under the covers.
My routine starts with an absurd pair of glasses. If you wear normal glasses, you’ve probably been offered special clear coatings that promise to filter blue light. Studies suggest they don’t do much. Real blue-blocking glasses aren’t sexy.
Frankly, they aren’t a realistic solution for most people, either.
The good ones have deep orange, red, or amber lenses that wrap all the way around your eyes so light can’t get in from the sides. Serious manufacturers offer a spectrum report that shows how much blue light gets in.
“You shouldn’t be able to see much blue,” says Håvard Kallestad, director of the sleep and chronobiology research group at the Norwegian University of Science and Technology.
The special blue-light goggles I have were made for people who work with lasers that need eye protection. I put them on and looked out the window.
There’s a store with a blue neon sign down the street. With my glasses on, the light from the sign vanished. Bullseye.
Thomas Germain is a senior technology journalist at the BBC. He writes the column Keeping Tabs and co-hosts the podcast The Interface. His work uncovers the hidden systems that run your digital life, and how you can live better inside them.
I sat down on the couch, thinking about the sacrifices I make for journalism. I scrolled through Instagram. It looked… orange. The whole point of what I’m doing is to see how light affects my sleep, so I didn’t change anything about my phone, TV, or computer habits. But the glasses are just the beginning.
“I think you need to turn your apartment into a cave,” Kallestad says. “Just block light from entering and use candlelight.” Modern LED lights produce a ton of blue light. Old school incandescent bulbs make much less, but candles are almost blue-free.
It’s never really dark where I live in New York. So, I covered my windows with blackout curtains, with only my phone and a couple of flickering candles standing between me and the inky darkness. I wasn’t sleepy yet. It was going to be a long couple of weeks.
My blue period
I use a sleep tracker to monitor my rest. It’s not good enough for real science, but it’s a rough indication. The quality of my sleep didn’t seem to change much during my experiment. But I did notice some differences.
Towards the end of the second week, I found myself a little more motivated to get into bed on time, and it seemed easier to fall asleep.
The amount of time I spent asleep didn’t change in any meaningful way by the end of my experiment, but the time I fell asleep and got up in the morning was a little more consistent. Was this because I blocked blue light? Hard to say, but it felt like a big victory.
