Our circadian rhythm (which dictates our sleep patterns) is guided by the natural light of the sun and moon. But in the 21st century, we’ve created 24 hours of unnatural daylight, by filling the world with streetlights, fluorescent bulbs, video signs, screens, and even our alarm clocks. These artificial light sources are a major contributor to sleep disruption.
Here’s how it works. In the morning and midday, the blue light in sunlight is a cue to our body to wake up. And our brains don’t know the difference between a sunrise and the blue light from a mobile phone. As a result, we feel alert and energetic, and functions such as memory and attention span are improved. Blue light suppresses the release of melatonin – a key sleep hormone – so we feel awake when we should be dozing off.
Low melatonin production before bed affects both the quality and quantity of sleep throughout the night, leaving us foggy and cranky in the morning. Research has also made the connection between long-term nighttime melatonin suppression and serious mental and physical health conditions like depression, obesity, and cancer.
But there are things you can do to embrace the dark and regain a deeper sleep. Here’s your checklist for banishing blue light at night.
Get plenty of blue light during the day
Harvard Medical School’s Dr. Charles Czeisler demonstrated that exposure to natural blue light in the form of daylight keeps our body’s internal clock aligned with our environment by regulating our circadian rhythm. To support cognitive function and an optimistic mood, it’s good to get outside early in the day and enjoy the sunlight, which will also allow your body to make vitamin D.
Ditch screens at least 2 hours before bed
This gives your body time to start producing melatonin in response to the change from day to dark. Along with putting down your phone, it’s time to step away from your laptop, TV or tablet. If that leaves you wondering what to do of an evening, try reading, playing a board or card game, or going for a gentle after dinner stroll. You may find these tweaks improve your life beyond sleep.
Use apps that limit blue light
If it’s impossible or impractical to tear yourself away from your devices every night, try to mitigate the effects by installing an app that filters blue light. Search your app store for ‘Blue Light Filter’. You can also look in your mobile phone settings to see if it has a blue light filter feature built-in. You can also turn down the brightness on your laptop screen, as long as it’s not so low that it’s a strain to see clearly.
Wear amber-tinted glasses
Mid-eighties pop star Corey Hart may have been onto something when he sang about wearing his sunglasses at night. Wearing amber-coloured, polarised glasses for a couple of hours before bed blocks the blue end of the light spectrum. Research has shown that people who do this will produce melatonin even when using devices or exposed to bright light. It’s a great one to try if you work shifts, or have to fly long haul overnight.
Make your bedroom as dark as possible
When your bedroom is pitch dark, your body can keep producing melatonin throughout the night. Try installing blackout curtains. You can also keep regular curtains closed by using clothes pegs or a bulldog clip. And either use an analogue alarm clock, or turn your digital alarm clock away from you to minimise the light hitting your eyes. Turn off digital devices that give off any type of light (and use a ‘do not disturb’ function to prevent messages and notifications disturbing your slumber).