Sleep and Blue Light

What is blue light and sleep?


In my previous post regarding Sleep and exercise recovery, I finished by listing 10 behaviors to adapt to improve sleep hygiene and therefore try to improve the quality and quantity of our sleep. Number 10 on that list was ‘Strictly no gadgets in the bedroom’


During this post I’m going to explain in a little more depth the reasons why we want to avoid our gadgets when we start winding down for bed and in particular keep our bedrooms a strict no gadget zone!


So first of all what exactly is Blue Light? Well to put it very simply it is just a range in the visible light spectrum, and if anyone can remember back to our days at school and Physics class, we know that the light spectrum is measured by wavelength. Blue light sits around 400-495nm wavelength in that spectrum, which is considered a shorter wavelength higher energy form of light.


Of the spectrum of light waves emitted by the sun that our eyes can detect, it is the shorter “blue” ones that get reflected and bounced around most by the molecules in the Earth’s atmosphere. They are the reason the sky is blue.


Artificial Blue light sources are becoming increasingly common in our everyday environment. Our Exposure to blue light comes from a variety of today’s technologies including smart phones, computers, televisions, and lights.


So what is the relationship between Blue Light and sleep? Well it all comes down to something called our circadian rhythm. Otherwise, known as our biological clock, the approximate 24-hour cycles of our physiological processes. Think of this biological clock as a simple day and night rhythm that that makes us feel more alert or tired at regular times of the day and night.

Effects of blue light and Sleep.


So why exactly can exposure to Blue light disrupt our sleep? Well if we look at our body clock, there is a powerful hormonal messenger that is released around dusk that signals to our body that its nighttime, and the build up of this hormone after dusk is a strong signal for our body to prepare for sleep. This hormone is called Melotonin, and it builds up through the night and slowly decreases as we approach dawn.


In of itself Melatonin does not cause sleep, but it is a powerful indicator to the rest of the bodies systems to get ready for sleep. It’s like our internal alarm going off to let us know. This release of Melatonin would in the past coincide with the earths natural rhythm between day and night, obviously as the sun goes down Melatonin is released, we begin to feel tired, and then we sleep.


Thankfully we don’t all live in caves anymore and we have an abundance of artificial light, that can prolong our day and allow us to do many other things when the natural daylight has long since gone. This is where the problem begins when it comes to our sleep. It is this abundance of unnatural light that can play havoc with the bodies own messengers when it comes to sleep.


Artificial light then can disrupt our body clock and its natural release of its own all important chemical messenger by fooling it into thinking that its still daylight. However, unfortunately it doesn’t stop there as in 1997 blue light emitting diodes otherwise known as LEDs were invented. They had considerable advantages over incandescent lighting which included longer life spans and energy saving and became ubiquitous.


Unfortunately for us, the light receptors in our eyes that communicate daylight to our brains are much more sensitive to this shorter wavelength blue light, thus having a much stronger effect of suppressing melatonin release which has a knock on effect on our sleep patterns.

So why no gadgets in the bedroom?


Well to put it simply, even when we might have lower level lighting in the bedroom its very unlikely that we are going to stare directly into it. However, with your gadget, whether it is a Smart Phone, tablet or laptop we will be doing just that and even worse in very close proximity to our eyes.


Given the fact that these screens are LEDs and give off the shorter wavelength blue light we can begin to see just how this can interrupt the all important natural processes that occur before and when we sleep.


Therefore, to put it very simply, excessive exposure to artificial lighting and in particular blue light emitting LED screens during the evening and at bedtime can have a strong negative effect on our sleep.


Research studies have shown that reading a book on an iPad for several hours before bed, compared to several hours reading a printed book over a 5-day period suppressed Melatonin by over 50% at night. Researchers found that the participants in the study not only had a significant drop in Melatonin, but also the peak saturation was delayed by several hours and individuals also took longer to fall asleep after the iPad reading compared to print.

Welcome to the dark


Hopefully, we’ve now got a greater understand of one of the mechanisms of sleep and the importance of our circadian rhythm or body clock, and that one of the key factors that can influence our body clock when it comes to our preparation to sleep is light.


Obviously with the onset of artificial light, we can see how this can have a negative impact on our natural sleep patterns and our bodies processes to help us achieve this all important rest and rejuvenation period in our lives. And we can now understand exactly the impact that some of our modern technology can have especially when it comes to LED blue light giving screens.


So what can we do about it? Below you will find a simple list of actions that you can implement to give yourself the best chance of achieving that all important quality and quantity of sleep. These are some actions I have implemented personally, and when I take screen access away at nighttime and especially in bed I sleep better and feel more rested.


We don’t live in a perfect world, and it’s almost impossible to avoid exposure to artificial light and certainly modern technology but if we think about it a little more, and know the positives of limiting our screen time, it will be a positive step moving forward.


1. Try to expose yourself to some bright natural light throughout the day. This will help keep you alert and brighten your mood and also help you sleep better in the evening.


2. Try to avoid bright lighting and screen time in the evenings 2/3 hours before bed. If you have a dimmer switch in your lounge, take it down a notch. Get into the habit of creating a positive environment before sleep.


3. On most modern electronic devices today, you can find some sort of ‘night shift mode’ This lowers the screens brightness and dulls the stronger blue light frequencies and replaces it with warmer orange/red light. These can be set to come on automatically. Also, apps are available, and software for PC’s and lap tops. So if we do have to interact with our gadgets, it will lower the impact.


4. If you work later into the evenings or nightshifts with a lot of screen time, consider some blue light blocking glasses. These are relatively cheap and widely available.


5. Consider fitting some black out blinds in your bedroom, or if that’s not possible there are some good quality innovative sleep masks that are really comfortable. Remember that even when our eyes are closed, they are still very sensitive to light.


6. Think of using dim red lights for night lights. Red light has the least impact on our circadian rhythm and Melatonin production.


7. Make the bedroom a gadget free zone, and enjoy your sleep ! Sweet dreams…………….









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