Blue Light: Beware The Ways it'll Damage Your Sleep
- Scott Hickman
- Dec 5, 2020
- 4 min read
Updated: Jan 27, 2021
For a while now, there's been a debate on whether or not Blue Light has a negative impact on your sleep. In this article, I'll be discussing some of the studies that have covered this subject along with some of the solutions to reduce the amount of blue light you're being subjected to.
What is Blue Light?
Sunlight is composed of red, yellow, orange, green, and blue light rays and many shades of each of these colours, depending on the energy and wavelength of the individual rays (otherwise known as electromagnetic radiation). Combined, this spectrum of coloured light rays creates sunlight called “white light”.
Without getting into the details, there is an inverse relationship between the wavelength of light rays and the amount of energy they contain.
This means that the rays on the red end of the visible light spectrum have longer wavelengths and, therefore, less energy. On the other hand, rays on the blue end of the spectrum have shorter wavelengths and more energy.
Not all colours of light have the same effect. Blue wavelengths are beneficial during daylight hours because they boost your mood, attention and reaction times, however, studies suggest they're more disruptive at night.
What exposes you to Blue Light?
Although sunlight is the biggest source of Blue Light that you'll be subjected too, here are some of the others:
LED light
Fluorescent light
Flat-screen LED televisions
Computer monitors
Smartphones and tablet screens
Although you receive a lot less Blue Light from these sources than from the sun, it's the fact that we tend to use them more and more before going to bed that is of concern.
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Blue Light and your sleep
For a while now people have debated whether or not Blue Light can directly impact your sleep. We all have an approximately 24-hour internal clock that is known as a circadian rhythm, which is what helps our bodies determine when we feel tired and when we feel awake.
This rhythm is automatically regulated thanks to natural light and darkness, however, studies show that Blue Light can affect our circadian rhythm by delaying the release of melatonin, the sleep-inducing hormone.
This study published in the Journal of Applied Physiology suggests that the Blue Light emitted by computer screens has an impact on circadian physiology, alertness, and cognitive performance levels.
"A 5-h evening exposure to a white LED-backlit screen with more than twice as much 464 nm light (Blue Light) emission than a white non-LED-backlit screen elicited a significant suppression of the evening rise in endogenous melatonin"
This means that using any type of computer screen, smartphone, tablet or television that emits Blue Light before going to bed will affect your sleep.
Another study from the University of Toronto also concluded that Blue Light could slow down the production of melatonin. During the study, some participants were instructed to wear special glasses that blocked blue light wavelengths whilst the rest didn't. The results showed that the people in the study that wore these glasses produced more melatonin than those who didn’t and hence, had a better night's sleep.
These studies do seem pretty conclusive, however since then others have said otherwise.
In 2019, a group of researchers at the University of Manchester in the U.K. challenged that notion. After exposing mice to lights that were different in hue but equal brightness and assessing their subsequent activity, the researchers concluded that yellow light actually seems to disturb sleep more than blue. Warm-toned light, they hypothesized, could trick the body into thinking it’s daytime, while cooler blue light more closely mimics twilight.
It is important to note however, that animals studies don't always reflect the entire reality, as they often can't translate directly to human behavior. Furthermore, since rodents are nocturnal, they may respond differently to light than humans do. Finally the lights were also kept very dim, regardless of color, which may not property represent the bright lights of electronics.
Because of these conditions, the results of the study can't be taken too seriously, given how many previous ones have concluded that Blue Light has a negative impact on sleep.
How to minimise the effects
If you're worried that Blue Light might be affecting your sleep, here are a few solutions:
First of all, try and cut down on your screen time. By doing this you'll be subjecting your eyes to less Blue Light from being on your computer or smartphone. Here's an article I wrote to help reduce screen time and stay active.
Try not to look at your devices just before bed. Consider turning off your phone a few hours before bed to avoid letting Blue Light affect your sleep.
Consider buying Blue Light filtering glasses, they're widely available and can help to reduce Blue Light if you need to use your devices a lot during the day.
Blue Light screen protectors are also available to buy. If you think you'll forget to wear your glasses then blue light screen protectors can be a useful alternative seeing as you only need to apply it once.
Use different lights: LED light bulbs in your house can also emit blue light, so instead of using bright white lights, you could try switching to dimmer red lights closer to bedtime so you are exposed to less blue light.
The bottom line
The bottom line is that most studies conclude that too much Blue Light, especially in the evening, can have a negative impact on your sleep. How much it affects us is up for debate, everybody may not notice the same effects but it definitely can't hurt to try and minimise the amount of blue light we're be subjected too, whether it's from generally reducing our screen time or thanks go a pair of dedicated Blue Light glasses.
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