How Bedtime Screen Use Affects Teens’ Sleep

Screens are a core part of teen and tween lives, whether for homework, games, or social media. If you’re wondering how those devices impact their sleep, read on.

A teen girl laying on a couch looking at her phone.
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Teens and tweens are more digitally connected than ever, with 93% (ages 8 to 18) owning smartphones. According to Common Sense Media, they’re also spending more time online. Teen screen use topped eight-and-a-half hours a day as of 2021, reflecting a pandemic-related bump. Whether that screen time is for online learning, staying in touch with friends, or de-stressing, it affects sleep.

When kids stay up late gaming, texting and messaging friends, or doing homework, that online time can affect their sleep in a variety of ways. For one, that time actively eats into the time they’d spend sleeping each night — something critical at this age for their development and optimal functioning. When what they’re doing online is absorbing and arousing, they’re stimulated rather than relaxing into the optimal winding–down bedtime routine. And finally, most backlit devices emit blue light, which is the part of the spectrum that makes us feel more alert.

Kids, tweens, and teens

As kids get older, their screen use tends to increase. A study published last year found that close to a third of preteens (in this case, 8- to 11-year-olds) said that at least once a week, they received or sent texts or calls during the hours they were supposed to be sleeping. Unsurprisingly, about the same percentage said they did not get the nine-to-eleven nightly hours of recommended sleep for their age group, nor did they “rarely” or “sometimes” get even eight hours of sleep, which is substantially less than needed.

This may be due to a bit of FOMO, or, more accurately, a phenomenon known as “nomophobia” (for “no mobile phone” phobia), says Dr. Jason Nagata, an assistant professor of pediatrics at UCSF and the lead author of a 2023 study published in Sleep Health that looked at bedtime screen use by 10 to 14-year-olds.

That study found that 12% of preteens reported that they left their ringer on all night. Nagata points out this makes it easier to be awakened by phone activity. The obvious fix? Switch it off at bedtime.

Another recommendation, based on the study results: “If you wake up in the night, try not to re-engage with your phone,” says Nagata, who notes that 20% of the tweens and young teens in the

study reported using their phone or device in the middle of the night. “Once you check it, your brain is activated again,” he says.

The lure of social media

Kids under 13 aren’t supposed to have social media accounts, but many of them do anyway. Nagata says: about 20% of the 10 to 14-year-olds in the study had social media accounts despite some of them being technically underage. Another finding: Even after lights-out, 17% of the kids in the study reported being on social media.

Fear of missing out is a major driver. But teens are also motivated by a desire for social connectedness and a perceived sense of obligation to be available online for their peers. The peak time for this is right around bedtime, creating a self-reinforcing norm.

These factors dovetail with teens’ and tweens’ cognitive development, including their predisposition for short-term rewards (versus longer-term concerns such as getting enough sleep) and their heightened sensitivity to social validation.

“Kids are just incredibly worried about getting left out or missing something,” says Devorah Heitner, Ph.D., author of “Screenwise: Helping Kids Thrive in Their Digital World” and the forthcoming book “Growing Up in Public.” “Social media speaks to everything that makes us human, and especially for teenagers: wanting to be part of the group, wanting social affirmation, wanting novelty.”

Tech type and time spent online both matter

When it comes to the impact of screens on sleep, not all tech use is the same. Social media, for example, can detract in many ways. Kids and teens often log on via their phones, which not only emit blue light but are typically closer to their eyes than a TV or even a laptop would be, thus having more of an effect. And, of course, being online at bedtime or after lights out can cut into sleep time. Perhaps most concerning, though, is the potential emotional impact of social media. According to a Common Sense media report released in late March 2023, 70% of teen girls with moderate to severe symptoms of depression said that their social media use “interfered with their sleep at least once a week.” The relationship between mental health and sleep is considered bidirectional, with depression and other mental health issues affecting sleep and a lack of sleep exacerbating symptoms.

As you might expect, the amount of time that teens spend on social media matters too. A study published earlier this year, which surveyed close to 90,000 teens in North America and Europe, found that the teens who said they were online “almost all the time throughout the day” got to bed later and got less sleep overall than their counterparts.

Notably, the researchers pointed out that they were measuring active social media use – interacting with others – versus passive use or scrolling.

Another study released earlier this year found that active screen use – defined as gaming or computer use – had a stronger effect on teen sleep than watching television (a passive activity). When it comes to a correlated effect of active-versus-passive screen time, the researchers noted that sleep difficulties emerged after just two or more hours of active screen use, whereas it took four or more hours of passive television to trigger sleep issues.

Although watching television and videos might seem like similar activities, interestingly, they have key differences that, in turn, affect sleep. A study released last year found that watching YouTube, which might appear to be a passive activity, in fact, was associated with later bedtimes, but watching Netflix or a similar streaming channel had the opposite effect. Every 30 minutes teens spent on YouTube was associated with turning out the lights about 13 minutes later, but the same amount of TV time was tied to a lights-out time about nine minutes earlier.

Why the difference? The researchers indicated that it’s likely due to the unstructured nature of YouTube, “where content is endless and personalised to the individual viewer” via algorithm. Teens may intend to be online for a relatively short time but end up sucked in. As researchers note, 70% of YouTube viewing is driven by algorithm suggestions, and the recommended videos become progressively longer as the user’s time on YouTube increases.

Tips for balancing tech use and sleep for teens

So, what’s a parent to do?

First, recognize that tech use – and screen time – isn’t all bad. Whether we like it or not, screen time is an integral part of kids’ and teens’ lives that’s here to stay. The challenge is setting and sustaining realistic guidelines rather than attempting to eliminate tech entirely.

The American Academy of Pediatrics recommends logging off one hour before bedtime, as well as removing all devices from bedrooms overnight.

Keeping phones out of the bedroom gives kids “a fighting chance to get some rest,” Heitner says. Barring this, parents can also encourage kids and teens to use screen time trackers or similar apps to shut down social media access and other functionalities, she says.

Studies show that when parents set nighttime tech rules, adolescents generally get to bed earlier. And when they comply with those rules, the effects are even greater: earlier bedtimes and more total sleep time.

That said, the same study found that simply having rules in place but not enforcing them wasn’t a strong enough deterrence to counteract teens’ fear of missing out.

It may be then that working toward compliance is the best path forward. Kids who keep their phones on all night may feel more anxious at the thought of shutting off notifications and potentially missing out on an important message or update, Nagata suggests.

In this scenario, an abrupt change may be less effective than discussing the reasons for the tech rules and then allowing for a transition time.

For those who unwind with screen time, a transition to passive consumption could help. Explain to a teen that different types of screen activities can affect sleep differently: Watching a Netflix show is likely less problematic than using a phone in bed after lights out. In fact, studies show that phones are teens’ most-used devices both in the hour before bedtime and after they’ve gone to bed, and generally are used for the longest amount of time compared to other devices.

The bottom line for parents: Involvement is key. “It’s not that realistic,” Heitner says, “to expect younger or older kids to self-regulate around tech.”