Stay Up All Night On Your Phone? We Have Good News

Well... good-ish.
Maria Korneeva via Getty Images

If you stay up on your phone, you’re exposed to blue light. Blue light keeps you up and at ’em for longer ― it’s especially bad before bedtime. Right?

Well, actually, that theory could be wrong, a new study finds.

Of course, you shouldn’t stay up late too often, as slumber is great for everything from your brain health to your gut.

But researchers from the University of Basel in Switzerland and the Max Planck Institute for Biological Cybernetics in Germany recently found that, contrary to popular belief, blue light might not be public enemy number one when it comes to catching some Zzzs.


I know!

Scientists researched how the colours our eyes are exposed to can affect our biological clock ― including how we sleep.

Previously, researchers thought that blue light, such as the type that emits from our phones and laptop screens, was confusing to our body clock because it mimics the frequency of daylight.

So, the theory went, our minds think it’s go time while we’re surfing the web at 3AM, making it harder to nod off.

But University of Basel chronobiologist Christine Blume says that “A study in mice in 2019 suggested that yellowish light has a stronger influence on the internal clock than bluish light.”

To see how the light affected people’s sleep, Blume and her team studied eight men and eight women over 23 days.

After getting them used to a certain bedtime, participants got exposed to an hour of “white” and “blue” light after their bedtime.They were then observed to check for the effects of different light on their brain waves.

There was “there was no conclusive evidence” that blue light was any more damaging to peoples’ sleep than any other light, the researchers found.

So... can I just scroll my phone as long as I like?

Sorry ― no. The research found that all light is damaging to your slumber ― but it just doesn’t seem like blue light is uniquely bad.

In fact, the study suggests that brightness matters more than the hue of the light involved ― so if you must go on that 2am deep dive, keep the screen as dim as possible.

The researchers recommend turning down all sources of light as you wind down, including your phone.

“Short-wavelength light — misleadingly often termed ‘blue light’ — should be reduced in the evening, for example by dimming computer screens and using a night-shift mode. Avoiding screen time before bed can also help, as the things we do on our phones often delay sleep,” Blume said.

And it’s important to bear in mind that this is a small study, which only contained 16 people.

Still, if you hear people bang on about blue light while you’re three Wikipedia pages deep in a fascinating wormhole, at least you have something to say back to them now...