Blue light word

By Dr Jessica Thatcher 

Work may be keeping you up at night, but not the way you think.

“Why is your phone yellow?” It’s a question I am often asked by people concerned there is something wrong with my phone. All are astonished when I inform them my phone screen is yellow on purpose.

Screens like phones, laptops and TVs emit blue light.

On the light spectrum, blue and red sit on opposite ends and are differentiated by wavelength. For red, think of it as a wide, slow, smooth wavelength and blue as being has a very short, sharp, fast wavelength.

The sun also emits blue light. As the sun rises to its peak, the amount of blue light we are exposed to increases and as the sun starts to descend, the amount of blue light we are exposed to gradually decreases until it’s dark. The increase in blue light increases our alertness. The natural decrease in blue light, tells our brain it’s nighttime so our brain can prepare us for sleep.

Normally, after the sun sets and the blue light decreases, it triggers our brain to produce and release melatonin, which is a hormone produced in the brain by the pineal gland. It is responsible for our sleep wake cycle (circadian rhythm). Higher levels of melatonin will make falling and staying asleep easier and usually results in a more refreshing, better quality sleep.

Is our brain making melatonin after the sun sets or is it disrupted because of the artificial blue light we are exposed to?

Different studies have suggested that artificial sources of blue light closer to bedtime can affect melatonin.

A study by Harvard University found that blue light suppressed melatonin production and circadian rhythm for two times longer in the participants exposed than those exposed to green light. Green sits next to blue on the colour spectrum, so we can speculate that people exposed to red light, which is even further away on the colour spectrum, would have a bigger difference.

Another study from Toronto, Canada found that if its participants used a blue light filter/blocker while being exposed to high level of blue light, they did not suffer from a lack of melatonin production.

These studies both suggest that if you attempt to decrease your blue light exposure, especially two to three hours before bedtime, it will help with falling sleep and waking up refreshed.

There are various ways you can minimise your blue light before bed. Avoiding screens of all kinds is the best, however, not always practical. Here are some other ideas:

Wear sunglasses or red lens glasses;

Decrease the brightness of your screens i.e. phone, laptop, TV;

Utilise dimmers on your light switches (if you have one);

Activate inbuilt blue light filters (available on smartphones and some computers); and

Install f.lux software on your computer to decrease blue light.

Take the plunge! Make your phone screen yellow, like mine, and after a few days you will hardly notice … that’s until you turn it off and get blasted with all that blue light.