A recent article in The Sydney Morning Herald shared data from a sleep app that claimed that Australians' self-reported mood upon waking up ranked 83rd out of the 91 countries tracked. Australian’s are not getting enough sleep and they are waking up tired and grumpy. Insufficient sleep can negatively impact all aspects of your life from your health to your career.
However, in this 24/7 world sleep can easily evade us. A key reason for this is that we can’t switch off. Not just metaphorically switching off, but also in literal terms. It’s hard to avoid the constant allure of our devices for work, study, news, socialising and entertainment. But what effect does being so switched on have on our sleep and consequently our overall health? The blue light emitted from our devices may be more dangerous than you thought.
What is blue light?
The electromagnetic spectrum is made up of a range of different types of lights and rays. The part of the spectrum humans can see is called visible light. Visible light consists of a range of colours that travel in waves. Each colour has a different wavelength that varies in length and strength. Blue light has a very short wavelength and therefore produces a high amount of energy. This means that blue light, and its neighbour on the spectrum - ultraviolet light, can have a powerful effect on the human body.
Where is blue light found?
Traditionally, humans were only exposed to blue light during the day. The sun is the original and most natural source of blue light. However, modern humans are flooded with blue light way after sundown. Artificial sources of blue light include digital screens, electronic devices and fluorescent or LED lighting. This includes our TVs, computers, tablets and smart phones. The light from electronic devices is “short-wavelength-enriched,” which means it has a higher concentration of blue light than natural light. For comparison, there is almost no blue light in candle light, which is why it feels so natural and calming.
How does blue light effect sleep?
Because humans evolved with light being a signal to the brain that it is time to be awake, all the extra light we are being exposed to is confusing for our bodies. Our natural sleeping and waking cycles, known as our circadian rhythm, is getting muddled by all the artificial light. Think of it as similar to a feeling of jetlag.
This occurs because blue light suppresses the body’s production of melatonin. Melatonin is sometimes referred to as the sleepy hormone because it signals to your body that it is night time and time to sleep. The pineal gland in the brain begins to release melatonin a couple of hours before your usual bedtime and melatonin levels peak in the middle of the night. Therefore, blue light exposure in the evening causes a circadian delay, or resets the body clock.
The reduction in melatonin not only makes it harder for you to fall asleep but studies have shown that is also reduces the amount of REM (rapid eye movement) sleep that you get which will leave you feeling sluggish in the morning.
Short wave blue light has been proven to have the biggest impact on melatonin production. Humans are so sensitive to what we know as blue light, that exposure to blue light still effects the circadian rhythm of people who are otherwise totally blind. Backlit, portable screens that shine directly into our eyes are the most disruptive to our circadian rhythm. The fact that we can easily use these devices in bed and hold them very close to our faces compounds the problem.
Recent studies have shown that these changes to our natural circadian rhythms influence organ function, impair thinking and have been linked to depression, obesity, diabetes, tumours and cancer. This means that circadian delay could have far-reaching consequences for our health and wellbeing.
Secondary to the light’s effect on our body clock, the flickering properties of blue light also places stress on the body. High energy wavelengths flicker more than other wavelengths. This flickering causes eyestrain, headaches and physical and mental fatigue.
Using devices in bed is also creates learned associations between bed and working or socialising. Sleep experts agree that bed should be a place for sex and sleep only. Plus, laptops and phones are way too engaging, interesting and even stressful to allow your mind to relax and drift off to sleep. Research has found that these kinds of interactive devices increase alertness more than passive forms of technology use such as watching TV.
What can you do?
There are a few things we can do to reduce the effect that artificial blue light from electronic devices has on sleep health.
A lot of new devices come with some form of ‘night mode’. This feature will tone down the blues in the screen and give the screen an orange tinge. Once your eyes adjust the change is barely noticeable. If your device has this setting then activate it after dinner each night. Some devices will allow you to put the night display setting on a regular timer. E-readers commonly have an option to invert the text so it’s white on black. If your eyes can adjust to this format it is better for late night reading.
There is also downloadable software (and apps) that can adjust the blue light levels on your screens. For instance, the free program, f.lux, adjusts screen colour according to your preferences, your wake-up time and local sunset and sunrise times.
Another option to prevent your eyes soaking up those blue rays is to invest in a pair of blue blocking glasses. These glasses can be worn at night, before bed, to protect your eyes. Newer versions of these glasses are quite stylish and could be worn at the office when you need to work late.
Try to use warm light in bedroom and bathroom spaces that you use at night. This could mean ditching the energy efficient lighting or just going for a lower wattage. If you, or your children, use a nightlight, make sure it’s one with a soft red or orange glow.
The last, and probably most unpopular way to avoid the damaging effects of blue light from device screens is to switch them off. Declare your house a screen free zone after a certain time of night and stick to it. If you have your phone in your bedroom at night make sure it’s on silent or aeroplane mode so you are not tempted by notifications. It is easier said than done, but could go a long way towards helping your family sleep better and longer. According to Australian sleep researcher, Dr Sarah Blunden, "sleep is the foundation of all physical and mental health.”
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Nice article! Red light bulbs, F.lux, and blue blockers if you need to use computers at night https://www.patreon.com/posts/14530810
Sunlight exposure in the morning also helps prevent artificial light induced melatonin suppression at night.