Blue Light: Friend or Foe?

There you are, gazing at your beloved iPhone, tucked up in bed reading the latest Facebook updates. The next morning, you wake up with a swamp for a brain, fighting yourself to not hit the snooze button because you know you need to get to the office on time.

‘Blue-light’ has become a bit of a buzzword recently and I think we all have some idea of how we should be avoiding our phones and laptops just before bed. But why is it really that bad? Is it just because your brain can’t quite switch off or does it go a lot deeper? Today, I am going to show you the damage blue-light is doing to our bodies, how it disrupts your hormonal production and what you can do to limit your exposure.


What is Blue light?

When physicists discuss light, they are referring to the entire spectrum of light, known as the electromagnetic spectrum. As humans, we can only see light in the ‘visible range’ and this comprises of the colours of the rainbow (hint: Richard of York…). However, this visible light is only a small part of the light spectrum and as you can see below it includes: gamma rays, X-rays, UV, infrared, radar and radio waves etc.


Today we are going to focus on the visible light, and particularly the blue light range (with wavelengths of 381nm to 500nm):bluelight2


Sources of blue light

You can see in the charts below where blue light rears its ugly head. The first image shows the spectrum of daylight, which although appears to have a lot of blue, it is relatively well balanced and is ‘washed’ out by the rest of the spectrum the sun offers. We then move to the incandescent bulb (remember those old bulbs that gave out a lovely warm glow?), which has very little blue light. However, these are now practically redundant in the world today as they are deemed energy inefficient. The real problem is in LEDS where there is an extremely concentrated dose of blue light, hence the big spike on the diagram. They have four times the amount of blue light than the other light frequencies. Fluorescent light bulbs aren’t much better!



This spike in blue is intentional by the manufacturers of LEDs as they are trying to make them more ‘energy efficient’, but they have given little thought to our health as we are about to find out.


Circadian biology, melatonin and hormone production

Circadian biology is the single most important process in our bodies. Without it, you wouldn’t wake up in the morning, you wouldn’t function all day and you wouldn’t be able to recharge your batteries in a deep sleep.

Without pointing out the obvious, you know that the day comprises of 24 hours. However, our body’s main body clock runs over a slightly longer period. This means that the body clock takes external cues from light to signal the timing of morning and night.

Located in the centre of the brain in the region of the hypothalamus is the suprachiasmatic nucleus (SCN). Try saying it, it is really fun! The SCN is the main circadian clock in our body and works when light enters the eye, which activates neurons and are then converted into electrical signals that head over to the SCN. Without this process occurring, our bodies cannot comprehend what time of day it is. Our body cannot read the time on a watch and relies solely on this mechanism. Hopefully, you are starting to see why light is so important to us.

Perhaps, you are starting to make the connection as to why the wrong light at the wrong time of day can be potentially disruptive. By exposing ourselves to the concentrated blue of artificial lights in the evening, we are sending very mixed signals to our SCN. Over time, we confuse our bodies at a cellular level and it becomes disorientated as to what time of day it is and this is when the problems begin.

Hormone production relies on a circadian clock mechanism. To give an example, the body starts producing cortisol at around 4am in order to prepare us to wake up. I imagine many people who are up late at night watching TV have severe problems waking up due to low cortisol levels. These same people might also be very stressed individuals as their cortisol levels may increase throughout the day due to the mismatch between the actual time and the time perceived by our bodies. All hormones work on this system. A disrupted circadian body clock could be the cause of thyroid, pineal, pituitary and sex hormone issues.

A very important hormone to talk about is melatonin. Melatonin, where production is based in the pineal gland, is known as the hormone that induces sleep. This is what most scientists refer to when they say blue light exposure at night disrupts sleep – it is because melatonin production cannot commence. As soon as any blue light hits the eye, melatonin production immediately switches off, preventing you from sleeping.

What isn’t well known is that melatonin is an extremely powerful antioxidant in the body which allows it to: direct free radical scavenging (this is the stuff an antioxidant is trying to prevent from going round damaging your body); stimulate antioxidative enzymes; and increasing the efficiency in the mitochondria. Hopefully, this will give you an added incentive to ditch the screens!

Another hormone that gets affected is prolactin. Prolactin release occurs between 12-2.00 AM and is responsible for ensuring we get the correct cycles of sleep. This means without prolactin surging it is impossible for us to go through a normal sleep cycle causing us to miss out on the important REM stage. REM sleep is where our body is completely paralysed so that the body has a chance to repair and recover from the previous day. The other useful thing prolactin does is signal the hypothalamus to release growth hormone between 2-5.00 AM. Have you ever wanted a sexy body with very little fat mass? Then you need growth hormone to optimize your body composition! Missing out on sleep is a dodo’s game.


Myopia and macular degeneration

Myopia (short sightedness, i.e. you can’t focus properly on distances) is currently undergoing quite the surge in popularity thanks to its best friend, blue light. This is particularly troubling in Asia where they spend a lot of hours in front of screens. Today in China, up to 90% of teenagers now have myopia compared to 10-20% 60 years ago. In Europe it has doubled in the last half a century (now affects half of young adults). Some estimates suggest a third of the world’s population could be affected by myopia at the end of the decade! This study shows how, in chicks, myopia was induced by blue light and I think the rapid rise in cases since technology has boomed is too much of a coincidence.  


Macular degeneration is associated with the eye problems your parents are likely facing. Here the victim is the retinal pigment epithelial (RPE) cells and also the photoreceptors at the back of the eye. Here the blue light hits these cells and causes apoptosis (cell death). Scientists at the Paris Vision Institute carried out a study looking at what bands of light caused the highest rate of cell apoptosis in the RPE in cells, in vitro (in a petri dish):


As you can see, blue light is the quite the little bugger!


Destroying DHA

DHA is a type of an omega 3 fatty acid, mainly found in seafood and trace amounts in grass fed meat. DHA is the single most important food source to us, it is what separates us from the rest of the animal kingdom. Typically, the smarter an animal is the higher the levels of DHA in the body. I already hinted earlier how we can convert the energy from light (light photons) into electric current (Direct Current) in the body. I won’t get too technical just yet, this is a subject of a later blog, but DHA is the only fatty acid in our 600 million years that has the ability to convert light energy into usable electric current in our bodies.

And what destroys DHA? Blue light! Dr. Jack Kruse has really been the pioneer piecing bits of the puzzle when it comes to light and our biology and he says that too much blue light is a stressor as it depletes our cell membranes of DHA. Why is this important? ‘DHA fundamentally allows our cells to power up electrons with photons. DHA fundamentally takes light and turns it into electrical signals in cell membranes everywhere, but especially our brain’. Without DHA our bodies are running on a low battery and it could well be adding to symptoms of lethargy.


What can you do?

We want to do everything we can to avoid artificial light, with special attention in the evening. Here are some solutions:

1. Install f.lux on your computers. I keep this on during the day as any artificial blue light, even in the day should be avoided

2. Buy a screen protector for your iphone that blocks out the worst of the blue light spectrum

3. Buy Uvex blue-blocking glasses and put them on as soon as it gets dark. These have the most research on them. For the more fashion conscious you can get a pair of spectacles custom made with a BPI 550 tint. I am having a pair made at the moment so I can wear them out and about and not look such a dork as if I was wearing Uvex! Check out the graph below where you can see what an impact they have on the blue light from an iPad:


bluelight 7


4. During the day, switch to a pair of blue-blocking lenses that don’t make you look silly like the ones above… I recommend lenses by Zeiss or Essilor (see below) in the UK and BlueTech in the USA. These are for the more dedicated as you need to go to an optician and have them put into a pair of spectacles. What I like about them is it isn’t that obvious to average joe what they are!


5. Every morning, as soon as it is light, get outside and allow the sun to hit your eyes and face. This will help rebalance your circadian rhythm

6. Change your light diet… what do I mean by this? You want to make a conscious effort to change the light in your environment. A great jump is over to candle light at night. This is the easiest and you can simply pretend to your girlfriend you are being romantic. Or, if you are really whacky you can switch to UVA bulbs and red lights in your house.

I think blue light is a serious issue and it is only getting worse with the increase in use of LED technology. Over the next few months I will be writing more on how light affects our biology. For now, just remember the impact blue light can have on DHA, which is the fat responsible for allowing us to gain energy directly from the sun!

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Jamie Ward

Jamie Ward

Jamie is on a mission to inform the UK mainstream that they can live a better more optimal life! He loves spending his time working out or relaxing on a hot beach

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