We’ve all heard the same warning: Looking at your phone or another screen before bed is really bad for you. It may make it harder for you to fall asleep and prevent you from getting quality sleep. Most sleep doctors do suggest turning off screens an hour before bedtime; the National Sleep Foundation suggests setting a “digital curfew” for two hours before if you can, but if it’s not realistic, one hour or even 30 minutes is better than nothing.
The reality is that, for the majority of us, cell phones, tablets, and/or TVs are the last things we look at before we close our eyes. Our smartphones can sometimes feel like an extension of our bodies because we’re so (physically) connected to them. Screens in general have become such a prominent part of our lives that it can feel completely unrealistic to put them away earlier in the night. But according to sleep doctors, it’s a smart idea to at least give it a try.
Blue light physiologically impacts your ability to fall asleep
At night, your brain starts to produce a hormone called melatonin, which keeps your circadian rhythm on track and helps you fall asleep, according to the National Center for Complementary and Integrative Health. Being exposed to bright light suppresses melatonin production, says Philip Richard Gehrman, PhD, CBSM, a behavioral sleep specialist and associate professor of clinical psychology in psychiatry at the University of Pennsylvania’s Perelman School of Medicine. “Blue light has the strongest impact,” he adds, “and the types of LED lights used in most electronic devices are strongest in the blue part of the spectrum.”
The reason blue light is particularly bad? Dr. Gehrman explains that the very specialized cells in the eyes that feed into our sleep system and circadian rhythms, called retinal ganglion cells, respond strongly to blue light in comparison to other types of light.
Content consumption keeps you awake for longer
Beyond the light you’re exposing yourself to, there’s also the simple truth that it’s easy to get caught up in what you’re reading or watching, which leads to staying awake a lot later than you should, says Shelby Harris, PsyD, clinical psychologist in private practice in White Plains, New York, and clinical associate professor in the departments of neurology and psychiatry at the Albert Einstein College of Medicine.
Even if you’ve got the self-control to switch off Netflix after a reasonable number of episodes, depending on what you just watched or read, you may be too mentally stimulated to fall asleep anyway.
Screens can impact your sleep quality
So, what if you always scroll on Instagram or Facebook in bed, but have no trouble falling asleep? According to a 2018 research review, published in the journal Child and Adolescent Psychiatric Clinics of North America, some studies have found associations between screen time and reduced sleep quality. Specifically, the National Sleep Foundation notes that using devices right before bed delays the onset of REM sleep and reduces the total amount of REM sleep, which over time can lead to meaningful sleep deficiency.
If you feel like you wake up well rested and are energetic during the day, despite looking at screens before bed, then maybe it doesn’t have as much of an impact on you, says Dr. Gehrman. If you’re always tired despite sleeping seven to nine hours each night, that’s a sign you’re not getting quality sleep.
Dr. Gehrman notes that TV, in particular, can interfere with sleep long after you’ve dozed off. Sleep is one of those things that gets harder to do the more you try to do it, he says. (Anyone with insomnia gets it.) So, many people fall asleep watching TV because the background noise stops them from focusing too hard on falling asleep. “But there is evidence that even when you fall asleep, your brain is still listening to the TV. The shifts in lighting and sound can keep you from getting into a deep sleep,” Dr. Gehrman says.
Some screens are worse than others
“If someone asked me to design a device that had the maximum negative impact on sleep, it would be a cell phone,” says Dr. Gehrman. “It has blue light and you hold it close to your face.” Dr. Gehrman says he personally thinks that TVs aren’t quite as bad when it comes to the blue light issue because they are generally much farther away from your eyes. (Though it is arguably worse when it comes to the other reasons bedtime screens are a no-no.) He adds, though, that there’s not much science to prove or disprove this and there are experts who disagree with this theory.
Tablets can be just as bad as a phone, but newer versions of the Kindle have been developed to emit less blue light. The Kindle Oasis, for example, comes with an adjustable warm light feature. Dr. Gehrman says that putting devices on night mode or changing the light to be warmer is a good place to start, though there isn’t any evidence to say if it truly works or not. “It’s certainly better than nothing,” he says. Same thing goes with blue-light blocking glasses—there have been few studies to say whether they’re effective, but there’s no harm in trying them.
Changing your bedtime habits can make a difference
Good news: Just because you’ve already spent many nights scrolling on social media in bed, it doesn’t mean you’ve done irreparable damage and are doomed to a lifetime of poor sleep. Sure, you’ve probably missed out on some good quality sleep and accumulated some sleep debt, says Dr. Harris, but once you change your habits, you can turn things around.
She suggests ditching screens for a paper book or other non-electronic pre-bed activity. “A lot of my patients use adult coloring books now or puzzles. You can also listen to a podcast or guided meditation, just be careful not to stare at your phone.” It’s ideal to ditch the phone altogether an hour or so before bedtime, but it’s totally fine to look quickly if your new bedtime activity happens to require the audio on your smartphone. Oh, and no TVs in the bedroom, please.
Dr. Harris and Dr. Gehrman both recommend buying an actual alarm clock and leaving your phone in the other room overnight. That way, you won’t be tempted to check it if you wake up in the middle of the night.
And of course, remember that if you think screens are interfering with your ability to get a good night’s sleep, you don’t have to make a big change all at once. “What can be helpful is to just do it gradually,” says Dr. Gehrman. “If your bedtime is 11, make it your goal to just put down the phone at 10:45. Then eventually move it to 10:30.” A good hour buffer between screen and sleep time is great, but it’s a connected era and we’re all human. It’s totally okay to take some time to transition and slowly develop a better bedtime routine that finally sticks—if you think you need it.