Screens are now an integral part of our daily lives. They have become a true companion with multiple functions, accompanying the person from the moment he/ she gets up to bed, in the office as well as at home. Gradually blurring the boundaries between private and professional life. Its users are becoming increasingly aware of the harmful impact they can have on their daily life but also on their sleep. They represent a scourge for certain reasons, blue light being one of them.
But what is this famous blue light that everyone talks so much about?
Blue light is a part of the spectrum of light with wavelengths between 380 and 500 nano meters. It is emitted by the sun, but also by artificial light sources: LED bulbs and screens (tablets, televisions, computers, smartphones).
Its impact on sleep
Our screens emit a large amount of blue light. In humans, the so-called circadian rhythm is the one that allows the alternation between sleep and wakefulness.
However, at night, excessive exposure to light and especially prolonged use of electronic devices can disturb sleep or exacerbate sleep disturbances.
According to sleep specialist Steven Lockley of Harvard Medical School: “Blue light preferentially alerts the brain, suppresses the melatonin and shifts your body clock all at the same time, Your brain is more alert now and thinks it’s daytime because we have evolved to only see bright light during the day.”
Dr. Alon Avidan, who directs the Neurology Clinic at UCLA (quoted in a Chicago Tribune article) explains: “Some patients will watch TV and do computer work late at night and not suffer from insomnia or other problems,” he said. “But other people have what’s called hyper arousal. They can’t go to bed without reading email, and then they have a hard time shutting their mind off. Those are the patients for whom light exposure is having a greater impact and who are genetically more likely to be affected.”
However, some people are still, genetically much more sensitive than others to the effects of light exposure.
According to team leader Russel Johnson, researcher and professor of management at Michigan State University, “You could almost say that smartphones were designed to disrupt our sleep. They stimulate us intellectually until late at night. This makes it particularly difficult to put work aside, relax and fall asleep.
Today, the use and purchase of smartphones and other displays is on the rise and one in three people are reported to complain of sleep disturbances or insomnia.
The solutions
The first and most obvious, but not the easiest: simply switch off your mobile phone in the evening before going to bed.
Some smartphones have a “night shift” option that you can program so that it is activated about 2 hours before you go to bed.
There are also blue goggles that you can wear whenever you look at a screen.
