The idea that artificial light from screens is to keep people awake at night is wrong, says a group of scientists who have been studying the best type of lighting to fall asleep.
According to researchers, from the University of Manchester, the blue light of the devices is not the main problem.
To prove it, they exposed a number of mice to different light settings to study the impact.
The results, published in the journal Current Biology, suggest that the answer lies in how warm and bright the light is.
WHY DO THE STUDY?
All people have a natural cycle of waking up and sleeping every day.
Your biological clock is synchronized with the environment so that they are alert during the day and sleepy at night.
But experts have long suspected that exposure to artificial light could alter this alignment.
There is also an opinion about artificial blue light that comes from the screens of computers and mobile phones, which has a particularly strong effect.
WHAT DID THE STUDY FIND?
The team performed tests on mice, setting the brightness to high or low and changing the color from blue to yellow.
The bright light of any of the colors was stimulating, rather than relaxing, as expected.
But when the light dimmed, the blue light was quieter than the yellow light.
The principal investigator, Dr. Tim Brown, said the findings coincided with what happens in the natural world, with bright and warm light.
“During the day, the light that comes to us is relatively white or yellow and has a strong effect on the body clock and around dusk, once the sun goes down, the light turns more blue,” he said.
“Then, if you want to prevent light from having a strong effect on your biological clock, blue would be the way to go.”
On the contrary, bright white or yellow light was better for staying awake and alert.
WHAT DOES THAT MEAN?
The night mode setting for phones and laptops reduces blue light in an attempt to lessen the damage to sleep.
“Right now, what people often do is adjust the color of the lighting or visual screens and make the screens more yellow,” said Dr. Brown.
«Our prediction is that changing the color of the lighting is having exactly the wrong effect.
“It counteracts any benefit you can get by also reducing the brightness of the screen.”
AREN’T MICE MORE ACTIVE AT NIGHT?
Mice are indeed nocturnal.
But researchers say the basic way in which light affects the body clock is the same in all mammals, including humans, which means that the findings should apply to people.
Recommend more research to confirm.
Dr. Manuel Spitschan, from the University of Oxford, said: “This is a fascinating job, but we really don’t know yet that the same thing happens in humans. That is the difficulty with working with animals. »