How screen time affects our sleep

How life has changed in recent years. Love it or loathe it our lives seem to be ruled by the bright lights of our digital world.

Handheld devices like smart phones and tablets make it possible to be always on. But when we want to switch off and go to sleep those same devices can make the idea of a good night’s rest seem elusive.

Aside from making it hard to stop your mind racing after getting offline, what you might not realise is that the artificial light emitted from these devices can confuse our bodies.

Digital devices contain a short wave light, known as blue light, which suppresses the release of melatonin - the body’s natural sleep hormone.

As a result, you might find yourself struggling to get to sleep and when you finally do sleep, it might not be the quality rest your body is craving.

What is blue light?

No it’s not a disco for school children at the local community centre. It’s a high energy, short wave light that is emitted by the sun during the day – but it also radiates from smart phones, tablets, computers, televisions, electronic devices and even fluorescent or LED (energy saving) lights.

Short and long wave light can be described by thinking of a rainbow. It forms when light coming from the sun is split by the water in the air and shows you the longer and shorter wavelength lights. Short wave lights are the highest intensity and affect our bodies the most. Blue light is the strongest of the short wave lights and it hits the back of our eyes (the retina) and tells the body it’s day time – so we need to be awake and alert.

Exposure to blue light during the day is normal and perfectly healthy, but the problem arises when we’re exposed to blue light from devices at night. 

How blue light affects our circadian rhythms

Our body clock or circadian rhythm keeps our sleep cycle in check. It’s ruled by the amount of light and dark we are exposed to. Exposure to strong, short wave light, like blue light, at night time throws our circadian rhythm out of whack.

Before the advent of digital devices, our exposure to natural short wave light during the day stopped in the evening allowing our levels of the natural sleep hormone melatonin to rise, making us feel tired and have a great night’s sleep. But exposure to blue light from digital devices, fluorescent light or LED lights continues to suppress our melatonin levels (as if it were daytime) which tells our body we need to stay awake. This can make it harder to fall asleep, can affect the quality of your sleep and also make it harder to get out of bed in the morning.

Avoiding blue light at night

There are lots of ways to minimise your exposure to blue light in the evenings. It doesn’t necessarily mean you have to part with the devices we know and love. There are apps that can dim or recolour your screen or you could try a pair of sleep well glasses designed to filter blue light.

Sleep well - blue light glasses
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