How does blue light affect your sleep?

We are spoilt for choice when it comes to television, the internet and streaming services. Netflix is the new norm, and books lay dusty on the bookshelf. From screens to 24-hour stores lit up with LED lights, there is a large amount of artificial light being absorbed by our eyes. This artificial light, or more specifically the blue light wavelengths, can affect your body, and for those asking, “how does blue light affect your sleep?”, the answer might be more complex than you think.

Understanding the circadian rhythm

Before we discuss blue light it is first important to understand the circadian rhythm, the body’s natural wake and sleep cycle. According to Harvard Health Publishing (HHP), everyone has a slightly different circadian rhythm. The average length of a human circadian rhythm is 24¼ hours, aligning closely with sunrise and sunset. Until the creation of artificial lighting, people spent much of their evenings in the dark. This natural rhythm allowed the body to wind down and let the mind come to rest without artificial disruption. The sun, of course, is the earth’s major source of light and although the sun’s light does include blue light frequencies, we are not exposed to it after sunset. In fact, the light from the sun is said to play a crucial role in waking up the human body in the morning. Read more about the body’s natural clock in our article on how to care for your circadian rhythm.

What is blue light?

Alertness, hormone production and sleep cycles are all impacted by blue light, but what exactly is blue light? Blue light is a natural part of the electromagnetic spectrum, and more specifically part of the visible spectrum, which is the part that humans can see with the naked eye. See the image below to understand where blue light sits on the electromagnetic spectrum.

blue light on the electromagnetic spectrum

Blue light is not intrinsically bad, as the media sometimes portrays. The biggest source of blue light is actually the sun and that light is helpful for our body clocks and mental health. However, the amount of artificial blue light that our bodies are exposed to after sundown is a cause for concern. Artificial blue light is emitted from our electronic device screens, LED lights and fluorescent lights. This blue light can suppress melatonin (the sleepy hormone) production in the body, which leaves us feeling alert and responsive. Essentially, the artificial light from our devices, etc. is tricking the brain into thinking it is still daytime.

What are the sources of blue light?

As mentioned above, the sun is our main source of blue light, this light stimulates the brain and can bring on alertness, elevate the body temperature and increase the heart rate. Human bodies have spent hundreds of thousands of years evolving and our bodies are not only accustomed to natural blue light, they rely on it. Blue light from the sun tunes our circadian rhythm and can set the body up for a good night’s sleep. However, sources of unnatural blue light are a more recent development in human history. These sources are disruptive to the body and can have the opposite effect to natural blue light, particularly when exposed at night. The common sources of unnatural blue light include:

Fluorescent lights
LED lights
Smartphones
Televisions
Computer screens
Tablets
E-readers
Video game consoles

How does blue light affect your body?

Blue light affects the body in many ways that we know of and possibly some we don’t know about yet. Aside from disrupting sleep patterns, unnatural blue light can cause digital eye strain through the unfocused visual ‘noise’ of short-wavelength, high-energy blue light. Common signs of digital eye strain include eye pain, headaches, blurred vision, and neck and shoulder pain. Interestingly, blue light is also used for therapeutic purposes for a range of things from acne treatment to treatments for seasonal affective disorder.

How does blue light affect your sleep?

One of the main concerns associated with artificial blue light is the effects it can have on your sleep. Sleep patterns seem to be most impacted when screens are used long-term, held very close to the face, and of course, after sundown. As discussed earlier, blue light suppresses melatonin production, which can make your body think it is time to be awake. The question now turns from, “how does blue light affect your sleep?” to “how can I ensure blue light does not affect my sleep?”

How can I ensure blue light does not affect my sleep?

Between natural and unnatural sources, the body is exposed to a significant amount of blue light every day. Natural sources will keep the body in tune with its natural sleeping pattern while unnatural sources should be limited, particularly after dark. Understanding and respecting your circadian rhythm can be beneficial to your sleep quality and long-term health.

There are several ways to protect yourself from the dangers of artificial blue light, and these include:

Keeping a sleep routine. Getting up and going to bed at the same time every day helps to regulate your body’s circadian rhythm.
Avoiding screen time after sunset. If you can’t manage this, try to switch off an hour before sleep time, to give your body a chance to wind down.
Absorbing as much natural blue light during the day as possible. This is particularly important in the morning when you first wake up.
Use ‘night mode’ on your smartphone and an app or setting on your computer to turn down the blue light after dark. Also, turn down the brightness of your screen and don’t have it too close to your eyes.
Turn off artificial lighting after dark, particularity if you have fluorescent or LED lighting. It’s a good idea to have warm, low-wattage bulbs in your hallway and bathroom for late-night bathroom trips too.

Blue light filtering glasses

Another way you can protect your eyes from blue light is to wear blue light filtering glasses. Blue light filtering glasses are a must for people who work at a computer all day. They are great for eye strain and fatigue as well. Our favourites are Baxter Blue‘s Sleep range. They not only look stylish but they protect your eyes from harmful blue light when looking at screens. We’ve put a few of our favourite styles below.