Posted on 31 May 2024

It’s an all-too-familiar phenomenon – lying on your side in the dark, your face lit up by an array of colours and lights as you scroll endlessly through your social media feed, occasionally glancing at the time as “just one more video” turns into another thirty minutes or more. In the morning, your dark circles have grown and you’re even more sleep-deprived than yesterday.

There is no question, modern society has an unhealthy relationship with technology, not least the portals of activity we keep within arm’s reach: our smartphones and portable devices. While we used to switch our old phones off before turning in, technology is now coming with us to bed and impacting how we sleep, when we sleep, and the quality of that sleep. However, it’s not just missing our bedtime that is making our sleep worse: there is an intrinsic factor to using mobile phones before sleep that makes it harder for us to sleep well. And it’s not just the light transmitted by our devices – and what it does to the primitive areas of our brain involved in the sleep-wake cycle – that makes it harder for us to switch off.

In all fairness, the light that comes out of our devices is a wavelength of light called blue light, which emulates daylight. When the rod and cone cells in our eyes encounter blue light, it initiates a cascade of reactions in the brain and throughout the body to promote wakefulness. This mechanism is linked to increased wakefulness when there is sunlight (more blue light) and sleepiness when there is less, like around sunset (less blue light). This is an ancient evolutionary mechanism, and explains how our ancestors adapted to be active during the day and to rest at night. Consequently, if we’re taking in more blue light from our devices in the evening and at night, this will logically promote wakefulness, delay the release of the sleep hormone melatonin, and make us more inclined to stay awake longer.

But this doesn’t tell the full story; if light was all it was, we wouldn’t have the “morning lark” vs. “night owl” phenomenon, where some people find it easier to get up in the early morning and sleep early while others are more naturally inclined to stay up later and get up later. Your individual genetic code influences all the signals your body sends and therefore how your body responds to light level, meaning everyone should have a different level of sensitivity to blue light. So why are we all finding it difficult to fall asleep after using our phones?

Well, as we’ve strayed further away from our prehistoric way of life and into the present day, there are more and more bright colours and loud sounds trying to grab our attention. Our bodies are finding it harder and harder to relax and wind down, with all the stimulation (including, but more than, the blue light) from our televisions, phone screens, and other devices causing havoc in our brains. Watching TikToks or answering emails requires focus, keeping your brain alert – i.e., not ready for sleep.

Dr Michelle Drerup, a sleep medicine expert, takes this approach: "Studies that have really shown support for light’s impact on sleep onset and melatonin production are much more like people using screens for two hours straight prior to bedtime [instead of saying] ‘I'm going to, an hour before bed, check to make sure I don't have any messages I need to respond to, look over my next day and then put it aside and do something to relax.’".

What’s more, using our phones before bed means we could encounter content which might wind us up, scare us, annoy us, or make us laugh – drawing us in and cause an emotional reaction. This fires up parts of the brain linked to alertness and cognitive processing, the opposite of what we need when we’re trying to rest. Just watching content like this prolongs falling sleep, which consequently delays REM sleep and how much good quality sleep we get. These emotions might delay the onset of sleepiness, and, lying in bed not getting to sleep, we pick our phones back up again, delaying the inevitable even further.

The process of creating a health sleep environment is often referred to as “sleep hygiene”. Using technology where and when we should be sleeping has meant that the lines between restful time and wakeful time have become blurred; improving your sleep hygiene will re-introduce these boundaries, and therefore make it easier for your brain to settle down.

There are a few things you can do to try and combat the use of technology in bed and to improve your sleep hygiene. A lot of research into the effects of devices on our REM sleep and quality of sleep comes from children, and we lack critical empirical data that we can use to definitively prove why late-night tech usage might be detrimental in adults – but even anecdotally, we all know it does more harm than good. Here are a few steps you can take to establish a more mindful, natural sleep routine:

  • Set a consistent sleep schedule

  • Try and limit use of technology at least an hour before bed

  • Try and wake up at the same time, even on weekends

  • If you have to use technology, try and use low blue light modes

  • Take up analogue instead of digital practices to help you sleep – reading, stretching, meditating

  • Exercise at least 150 minutes a week to help sleep quality

  • Dim the lights when the sun sets to set the environment for sleep

So goodnight, and happy sleeping!

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