Why Blue Light is Ruining Your Sleep (And What to Do About it)
We’ve all experienced a bad night’s sleep at one time or another, and know the impact that being sleep deprived can have on your day. Even one night without sleep can lead to memory troubles and symptoms of anxiety, and in the long term, poor sleep can increase the risk of developing serious health conditions like heart disease.
There are a lot of factors which can reduce your sleep quality (or stop you from being able to fall asleep altogether), like consuming too much caffeine in the afternoon or not getting regular exercise. One of the biggest factors for sleep which often gets overlooked is our exposure to blue light. But what exactly is blue light, and how does it affect our sleep? To properly answer that, we need to dive into a bit of the science of sleep.
Body Clocks, Sleep and Light
Our bodies have an internal ‘body clock’, called the Circadian rhythm, which controls when we wake up and when we sleep, and helps us to feel alert during the day and sleepy at night. This body clock operates under a 24-hour time cycle with relatively equal amounts of light (day-time) and dark (night-time). During the day we are exposed to bright light, which prompts our bodies to secrete hormones like cortisol, which makes us awake and alert. When the sun goes down and we are exposed to darkness, our bodies switch to secreting a different hormone called melatonin, which makes us feel drowsy and ready for sleep (1).
Exposure to bright lights at night (such as the overhead lights in our house and the light from TV and phone screens) tells our body that it is still day-time and we need to stay awake. These bright lights actually send signals to our brain to stop secreting melatonin (1). Suppressing melatonin like this means we don’t feel as sleepy and night and we end up having poorer quality sleep (and less of it).
While all bright lights have an effect on melatonin, blue light (which is a short-wave light) has the biggest effect – it is up to three times more powerful than other wavelengths of light (2). This is a problem when it comes to our screen-based technologies such as our phones, TV and computers, because they emit large amounts of blue light, significantly disrupting our body clock and our sleep.
What Can be Done to Help?
The good news is there are plenty of ways you can reduce the negative effects of blue light on your sleep. Below are a few science-backed ways to get you sleeping better!
1. Give yourself a screen-time curfew
In an ideal world we would completely steer clear of screen-based devices at night, but of course this isn’t practical for most people. If you can’t avoid night-time screen use altogether, set yourself a curfew – switch of all screens at least 60-90 minutes before bed time. This gives your body a chance to build up enough melatonin to help you enter quality deep sleep.
Not sure what to do for those 90 minutes? Give these a try:
- Have a hot bath or shower
- Chat or play a board game with the family
- Do some gentle yoga or stretching
- Go for an evening walk
- Try mindfulness meditation
- Get creative! Draw, write, sing, or even drag out that guitar that’s gathering dust in the spare room
- Try journaling
- Read a book or magazine
2. Reduce the amount of blue light being emitted from your screens
Many electronic devices now have built-in “night” modes, which can easily be set up through the device’s settings menu. There are also some great apps such as “twilight” and “f.lux”, which are available for free. These apps reduce the amount of blue light being emitted by your device to reduce its effects on your sleep. However, some studies have found that using these apps on their own might not be enough to help you sleep, so its important to also have a screen-time curfew (3).
3. Use blue light-blocking glasses
Blue light-blocking glasses work by filtering out the blue portion of the light spectrum, so that less blue light reaches your eyes. Studies have shown they are effective at counteracting the negative effects of blue light and can improve sleep quality and day-time functioning (4). There are a range of blue light-blocking glasses available, and some glasses retailers now offer prescription versions. If you’re considering getting a pair of glasses specifically for wearing at night to block blue light, look for a pair with a strong orange tint, as these are the type that have been most researched (5–7).
4. Dim the household lights at night
Switch off overhead lights and use dim lights (such as lamps) during the evening. Studies have shown this can help to increase melatonin production at night, helping us to get to sleep faster (8). One clever option for night-time lighting is to use Himalayan salt lamps. These pretty lamps give off a warm orange light, which is ideal for optimising melatonin levels at night. Some salt lamps also come with an adjustable dimmer switch, so you can set the light to the level that suits you.
5. Get out into the sunshine
Bright light exposure in the morning can help to counteract some of the effects of night-time screen use – but there’s a catch (9). Although artificial overhead lights are bright enough to suppress melatonin at night, a study from 2017 found that these lights aren’t bright enough to keep our body clocks in check the way sunlight does (10). Considering most of us spend over 90% of our time indoors, this is a big problem (10)! The easiest way to fix this is to make sure you get a good dose of sunshine in the morning, ideally sometime between 8-10am. This will help to make sure your daytime cortisol levels peak at the right time of the day, allowing your body to produce plenty of melatonin in the evening (11).
About the Author
Lizzie Stow is a degree-qualified naturopath from Newcastle, Australia.
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References
1. LeGates, T. A., Fernandez, D. C. & Hattar, S. Light as a central modulator of circadian rhythms, sleep and affect. Nature Reviews Neuroscience 15, 443–454 (2014).
2. West, K. E. et al. Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans. Journal of Applied Physiology 110, 619–626 (2011).
3. Nagare, R., Plitnick, B. & Figueiro, M. G. Does the iPad night shift mode reduce melatonin suppression? Lighting Research & Technology (2018) doi:https://doi.org/10.1177/1477153517748189.
4. van der Lely, S. et al. Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers. Journal of Adolescent Health 56, 113–119 (2015).
5. Burkhart, K. & Phelps, J. R. Amber lenses to block blue light and improve sleep: A randomized trial. Chronobiology International 26, (2009).
6. Esaki, Y. et al. Wearing blue light-blockng glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial. Chronobiology International 33, 1037–1944 (2016).
7. Schechter, A., Kim, E. W., St-Onge, M. P. & Westwood, A. J. Blocking nocturnal blue light for insomnia: A randomized controlled trial. Journal of Psychiatric Research 96, 196–202 (2018).
8. Rahman, S. A., St. Hilaire, M. A. & Lockley, S. W. The effects of spectral tuning of evening ambient light on melatonin suppression, alertness and sleep. Physiological Behaviour 177, 221–229 (2017).
9. Munch, M. et al. Blue-enriched morning light as a countermeasure to light at the wrong time: Effects on cognition, sleepiness, sleep, and circadian phase. Neuropsychobiology 74, 207–218 (2016).
10. Figueiro, M. G. et al. The impact of daytime light exposures on sleep and mood in office workers. Sleep Health 3, 204–215 (2017).
11. Smolensky, M. H., Sackett-Lundeen, L. L. & Portaluppi, F. Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases. Chronobiology International 32, 1029–1048 (2015).