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Blue light has a dark side

Jul 10, 2020

Understanding the colours of the spectrum

Light is made up electromagnetic particles that travel in various length waves, which emit energy. Every wavelength is represented by a different colour, and grouped into different categories which are: gamma rays, x-rays, ultraviolet (UV) rays, visible light, infrared light and radio waves - which altogether make up the electromagnetic spectrum. As fascinating as the human body is, our eyes are sensitive and can only see one part of this spectrum: visible light, which is seen in colours.

Why does blue light effect our sleep?

Not all the colours of visible light have the same effect. Blue light produces the highest amount of energy and are the most beneficial during daylight hours because they boost attention, reaction times and mood, however it seems to be the most disruptive at night time.

Blue light is found in many energy efficient light sources which include the sun, digital screens (computers, laptops, smart phones, tablets and TV’s) electronic devices and LED lighting. It stimulates sensors in the eyes to send signals to your brain’s internal clock, tricking it into thinking its daytime.

Good vs Evil

The truth is, you can’t avoid blue light. It’s actually everywhere around us. When you’re outside, light from the sun travels through the atmosphere. The shorter, high energy blue wavelengths collide with the air molecules causing blue light to scatter everywhere. In its natural form, your body uses blue light from the sun to regulate your natural sleep and wake cycles.

But not all is good, studies show, over time exposure to the blue light could in turn cause serious damage to your eyes. Because blue light waves are shorter, the wavelengths flicker more easily than longer, weaker wavelengths. This kind of flickering creates a glare that can reduce visual contrast and affect sharpness and clarity. This flickering and glaring may be one of the reasons for eyestrain, headaches, physical and mental fatigue caused by many hours sitting in front of a computer screen or other electronic device.

Sleepless blue nights

Light has a massive effect on our sleep. Humans are diurnal which means we evolved to sleep at night and it is easier to sleep in the dark than in the light - this is something called your circadian cycle.

5 tips on how to avoid losing sleep to blue light

• Many electronic devices now offer a blue light shield option that filters out the blue light from the device, such as on Apple there is a ‘night mode’. The result is that the screen relies more heavily on shorter red wavelengths that are less damaging to retina in your eyes. Redder wavelengths are also less powerful at suppressing melatonin and sifting the circadian rhythms.

• You can get yourself some blue light glasses. These are glasses with yellow lenses that block exposure to the harmful blue light, so that your brain doesn’t get the signal that it’s supposed to stay awake. These glasses can be beneficial for people who work in front of computer screens all day or night shift workers.

• Try to not use electronic devices at least an hour or two before bedtime. Instead of falling asleep to your phone screen, try reading a book or meditating to prepare you for sleep and stick to your sleep clock routine.

• Go outside during the day, and avoid staying in dim lit rooms throughout the daytime. Allow your brain to recognise the contrast between a brightly lit part of the day and the dark night. This is important in telling the brain that it is time to sleep at night.

• Keep your bedroom dark. You can use an eye mask to get to sleep or use blackout curtains. Use your bedroom for simply relaxing and sleeping, so create an atmosphere which is ideal for sleeping. Check out our ‘9 tips for a bed-ter night's sleep advice column for tips on how to do this.

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