Are Screens a Double-Edged Sword?

Everywhere you look, you can find doctors, therapists, coaches, parents, teachers, and even the National Sleep Foundation talking about how you should not look at screens at night.¹

Recommendations vary: You should turn off screens 3 hours before bed, 2 hours before bed, 1 hour before bed. Virtually everyone seems to base this recommendation on the "fact" that screens are bad for sleep.

But are they? Do we think this because we have been told it by social media? Apparently so. Is that suggestion actually backed up by a large and varied body of quality evidence? Apparently not.

The science behind screen time and sleep disruptions

Experts have known for a long time that this "no screens" suggestion isn't actually based on science. A recent analysis of over a decade of research was just published and shows us that the assumption isn't quite right. Let me summarize how I think we came to the no-screens suggestion by highlighting some points from the article:²

• We know from both old and new studies that bright enough blue light at night measurably increases alertness.
• We know from old and new studies that enough blue light at night delays the onset of melatonin release and can disrupt the circadian rhythm.
• We know that some older studies found that increases in alertness and delays in melatonin timing didn't actually measure the actual impact on sleep itself.

So, it was assumed that since they increased alertness and delayed melatonin onset (up to 90 minutes), screens created a problem with falling asleep. But what happened when they actually measured the sleep itself? There was virtually no impact.²

Looking at the last decade of studies summarized in the article, dim-light screens versus bright-light screens caused a difference of only 3.3 minutes in sleep. And a study of e-books versus printed books showed a delay of 9.9 minutes, even though melatonin onset was delayed by 90 minutes!²

A study in 2021 looked at the effect on sleep of the iPhone night shift feature, which warms the screen to reduce the blue tint of the light. It showed no difference between the night shift group and the normal screen group.³

When various studies examined blue light groups versus groups not using screens, there was a delay in falling asleep that averaged about 10 minutes. But some blue light-exposed groups actually fell asleep faster than the control groups, even with a delay in melatonin onset. So, it seems that falling asleep can't be solely down to melatonin.³

If it isn't the melatonin issue, maybe we should avoid screens because of the excitingness of what is on the screen? Apparently, that isn't as big a factor as we thought either.³

How different screen activities affect sleep

The article summarizes studies comparing young adults playing first-person shooter video games, watching TV, and being on apps. The maximum delay for these groups to fall asleep compared to a control group was 8.5 minutes, and one group fell asleep more than 5 minutes faster.³

People watching movies with cliffhangers had higher stress levels and higher pre-bedtime arousal, but they actually fell asleep 5 minutes faster. So, stress and arousal from an exciting plot didn't seem to affect the ability to fall asleep.³

One study compared a group using social media (Snapchat and WhatsApp only – much like my own 15-year-old!) for 30 minutes and to a group doing 30 minutes of progressive muscle relaxation and a control group that went straight to bed. The social media group slept 6 minutes less compared to the control group, even though the heart rate was lowest in the progressive relaxation group.³

So, on average, the content of what we are doing on screens also doesn't seem to matter a lot.

What are some other takeaways from the summary?

Even though the impact of nighttime blue light seems minimal, sensitivity to its impact at night is further reduced if people get a good amount of daylight versus sitting in a dark indoor place all day. There are lots of other physical and mental health reasons to do this anyway!³

These studies mainly looked at pre-bedtime screen use, with no delay in going to bed because of using a screen. But there does seem to be sleep disruption if people are using screens for certain purposes after their intended bedtime.³

What does that mean? People who are prone to getting into flow and losing track of time, and those who are not very risk averse, are more likely to stay on screens and interrupt their sleep opportunity. That is, they keep themselves up past their usual bedtime by getting too into it.

Social media is basically designed to keep us on the platforms, making sleep disruption more likely for these people if they stay up late using social media.

Understanding the two-way relationship between screens and sleep

The review authors propose that the relationship between screens and sleep is bidirectional, or two-way. Sleep disruption encourages screen use to pass the time, which then disrupts sleep through encouraging sleep procrastination. There's a lot more research to do on this, but the early research they summarize leans in this direction.

Is there a more real reason than blue light to leave your phone in the drawer downstairs at night? More research is needed to answer that question. But 1 take-home lesson for me and many others is this: The more something seems to be common sense, the more we ought to look at it carefully – especially if it is creating anxiety around sleep!

What do I tell my sleep therapy clients?

Anxiety and self-shaming about being on screens at night is common. Anxiety about that is probably more disruptive than the actual screen use itself. If you like cat videos, watch some cat videos. If you have a deep-seated fear or disgust of zombies, maybe don't watch zombie movies before bed (or in my case, ever, at all, at any time of day – because I will dream about it!).

Avoid picking up your phone to pass the time while awake. Non-algorithmic platforms, like regular television, are better.

Social media and screen use can cut both ways. Screens can be a tool we can use to enrich our lives. Or they can consume us and bring us further from the real riches in real life.

Excessive social media use overall is associated with mental health problems, and this may also be bidirectional. Mental health issues may make people want to be on social media more, and being on social media may contribute to mental health issues.⁴

Dependence upon anything can create problems. And those problems can make sleep issues worse. So, instead of asking whether screen use at night is problematic, perhaps ask whether an overall pattern of social media use is affecting your sleep.

Practical advice for managing screen time and sleep

I firmly believe that social media and screen use can be positive or negative, depending on how we use it! I have created very solid boundaries around socials that I'm comfortable with, and that includes my online work time.

Still, I sometimes fall asleep looking at knitting patterns on Instagram. It turns out the biggest risk of doing this isn't the blue light (and my partner would say it is definitely not how exciting the patterns are). It is probably more realistic to say that it is a bruised nose from dropping the phone on my face!

Have you ever felt guilty about your screen use at night? Have you ever noticed a difference in your sleep from using (or not using) your devices at night?