What is Blue Light?
The sun is responsible for emitting a rainbow of colours. Some of these colours are visible to the human eye, while others are not. The strongest lightwave emitted by the sun is UV, known as ultraviolet light. Most of us are probably well aware of ultraviolet rays despite it being one of the light waves we cannot see. UV rays are responsible for the production of vitamin D inside our bodies but it is also responsible for causing oxidative damage to our skin and eyes if we are overexposed. This is why it is so important we receive enough UV exposure each day but not too much without the protection of hats, sunscreen and sunglasses.
The second strongest light wave emitted by the sun is HEV-light, also known as high-energy visible light or just ‘blue light’. As the name depicts, we are able to see blue light and it is what makes the sky look blue in the absence of clouds. While blue light is created naturally it also comes from many artificial sources. Blue light is found everywhere we go. It is in our homes and in our offices given off from fluorescent and LED lighting. It is in front of our faces every time we turn on our computer or flatscreen TV and it is in the palm of our hand with every use of our smart phone, tablet and e-reader devices.
Just like ultra violet light, HEV-light has its’ purpose but it comes with a host of negatives when overused. During the day it helps us to react faster, think quicker and contributes to elevating our mood, making us happier people. While all of that sounds great, it is important to be aware that for all of us the amount of exposure to blue light has increased infinitely over the last few decades.
While the amount emitted by our devices is far less than the amount emitted by the sun, the amount of time we spend looking at our devices far exceeds what we are exposed to in the natural world. And the most harmful change of all is the amount of blue light we are being exposed to in the evenings. Evening exposure causes the most disruption and danger to our health because it disrupts our natural circadian rhythm. This disruption causes a cascade of affects which disturbs hormones and sleep and leaves us unable to function anywhere near our best.