How the blue light from your mobile phone affects your sleep
If your phone is the last thing you look at before you go to bed at night, you could be disturbing your sleep cycle. The blue light emitted from screens can interfere with our sleep by blocking melatonin (a sleep hormone) production.
Let's explore how screen time, the blue light from screens, and even household light can affect your sleep. And we have 5 tips for what you can do about it.
How blue light affects our sleep
We all know sleep is important for our physical and mental health. It restores and replenishes us.
But sleep deprivation doesn’t just make the next day much harder to deal with. Chronic lack of sleep has also been linked to a host of physical and mental health problems such as:
- elevated blood pressure
- being overweight
- low mood
And now, sleep specialist Dr David Cunnington says there’s growing evidence that night-time screen use and bright lights can stop us getting enough sleep.
He explains that this happens because normally, when you go to bed at night, the sleep hormone melatonin kicks in to help you drift off. Your brain’s pineal gland releases this hormone in response to darkness, making you feel sleepy. Then, in the morning when the sun shines, the light switches off your melatonin production.
And, according to Dr David, “If you have a source of blue light like your phone in front of you, your pineal gland thinks it’s the morning sun, so it stops producing melatonin. That’s why you don't get that natural sleepy feeling.”
Some of us are more light-sensitive than others
Maybe someone you know (possibly in the bed right next to you!) has no trouble falling asleep after staring at a screen for hours. But if you struggle to sleep after scrolling on your phone, you could be highly sensitive to light.
Research from Monash University shows that not everyone has the same sensitivity to light. The study found that some people are as much as 50 times more sensitive to light than others, reacting to normal evening home lighting as though it was bright outdoor lighting. Meanwhile, other participants had almost no response.
“That’s why general rules like ‘no screens for one hour before bed’ don’t apply to everyone,” Dr David says. “That 50-fold difference in sensitivity means that some individuals are exquisitely sensitive, so even a little light really messes with their sleep schedule. Meanwhile, others experience no effect, and everyone else is somewhere in between.”
How to cut the light and get better sleep at night
Here are Dr David’s top 5 tips to reduce your exposure to blue light at night to help improve your sleep.
1. Dim the lights
Dr David recommends practising ‘light hygiene’ to minimise the effect screens have on your sleep.
This means being conscious of the light around you, particularly once the sun's gone down. Light that's out of sync with the natural environment can have an impact on sleep and health.
“Bright, cold light (rather than soft, warm light) will confuse your body clock, keeping your melatonin levels from rising,” Dr David says.
2. Observe your own sleep patterns
We all have different responses to light at night, so take note of how screens affect your individual sleep patterns. If you stay up scrolling on your phone until 11pm, can you go to sleep straight away? Or do you stay awake for an hour or two afterwards?
3. Avoid endless scrolling
Online content is all about attracting and keeping eyeballs. One of the reasons social media exists is to provide engaging content that gives us a hit of dopamine – one of your brain’s feel-good hormones.
“The problem with that dopamine hit is that it wakes the brain up”, Dr David says.
So if you must use your phone, consider tip 4 instead.
4. Read a book before bed
Reading a physical, paper book is ideal. But according to Dr David, reading an e-book (even on your phone!) is less likely to disrupt your sleep than scrolling on social media.
According to Dr David, that’s because the content is linear and long-form, and your brain doesn’t jump rapidly from one topic to another.
5. Use orange glasses to filter out blue light
You can buy ‘gaming glasses’ with orange lenses that filter out blue light. They’re designed to reduce eye strain for anyone who spends hours continuously playing games.
They may look a bit unusual, but they do remove some of the blue light that hits your eyes when you’re working on a screen.
We’re learning more every day about sleep
But following Dr David’s tips above will at least potentially help remove one factor from the equation. And that’s worth sleeping on.
- Why is sleep important and why do we do it?
- Sleep for women: how to get better rest & improve your health
- Do hormones affect my sleep?
- Why do we snore (and how can we stop)?
Dr David Cunnington is a specialist sleep physician who helps his clients to treat their complex sleep problems while also promoting sleep health through education, research and advocacy.
Reviewed by the healthylife Advisory Board June 2021