We've seen many studies showing how bad late-night phone-checking is for our bodies, but new research confirms it – it's just not worth the hit your sleep quality takes for those last few minutes on Twitter or Facebook.
Participants in the new study were given special glasses that block blue light from devices like phones and televisions and were then asked to carry on with their usual "digital routine" late at night.
They all ended up falling asleep faster, sleeping better, and sleeping longer than normal. What's more, the researchers from the University of Houston found that levels of melatonin – the hormone released when our bodies think it's time to sleep – got boosted by 58 percent when the blue light-blocking glasses were worn.
That's a bigger boost than you would get from over-the-counter melatoninsupplements.
"The most important takeaway is that blue light at night time really does decrease sleep quality," says lead researcher Lisa Ostrin. "Sleep is very important for the regeneration of many functions in our body."
Blue light isn't inherently dangerous, and we get most of it from sunlight.
It boosts our alertness and regulates our internal body clock, by activating photoreceptors in the eyes called intrinsically photosensitive retinal ganglion cells(ipRGCs), which then suppress the production of melatonin.
The problem comes when this is happening late at night – essentially our bodies think it's still daytime, not time to doze off. That means we get low-quality sleep, and less of it.
This particular study only involved 22 participants, but despite the relatively small sample size, it's just the latest in a growing body of evidence that says using electronic devices late at night is a serious health problem. It really is time to change our habits.
Even the tech companies are catching on: night modes that cut down on blue light are now built into iOS, macOS, Windows, and Android, though if you're using a Google-powered phone the exact setting and setup process varies depending on the make and model.
Disrupted sleep is starting to become a real problem too: according to 2014 figures from the National Sleep Foundation in the US, based on 1,253 adults, up to 35 percent of us are getting sleep that's only "fair" or "poor".
45 percent of Americans said that poor or insufficient sleep had impacted their daily activities at least once in the last week.
That's not all down to blue light, but we know that a lack of sleep is bad for our health in all kinds of ways: research from earlier this year showed that when the brain doesn't get enough rest, it starts to clear out more neurons and synapses than it needs to.
Maybe it's time to step away from the keyboard earlier so that we'll be more productive the morning after.
But if you really can't cut out your late-night Instagram checking or Netflix watching, which are likely to keep your brain active besides suppressing melatonin, then a blue light filter is going to be the next best thing.
The researchers themselves suggest using blue light blockers like they did in their own experiment is the way to go if you want to keep busy.
"By using blue blocking glasses we are decreasing input to the photoreceptors, so we can improve sleep and still continue to use our devices," says Ostrin. "That's nice, because we can still be productive at night."
The findings have been published in Ophthalmic and Physiological Optics.