Blue light: the harmful effects of screens on sleep can be "easily reversed"


TUsing a phone or tablet in another room before going to bed is a common rule of sleep hygiene. But in reality, completely abandon the phone before going to bed forever is a big task. Fortunately, the results of a new experiment presented on Sunday show that the damaging effects of blue light on sleep can be "easily undone" after a short period of detoxification.

Although the constant use of the screen is a relatively recent phenomenon, it is clear that exposure has a definite impact on sleep, even if it is not the only aspect of modern life that prevents us from sleeping. the night. The evening's electronic exposure "potentially disrupts sleep," in part because of the blue light emitted by LED displays, such as tablets, phones, and computers, according to the American Academy of Pediatrics . One of the reasons that occurs is that blue light can prevent the release of melatonin, the hormone that regulates the sleep-wake cycle.

The new study, led by Amsterdam University Postdoctoral Researcher Dirk Jan Stenvers, Ph.D., in collaboration with the Dutch National Institute for Public Health and the Environment, showed that blue light actually had an impact on the sleep of 25 teenagers "frequent" users of the screen. But fortunately, Stenvers found that the effects can be reversed – with the right tools and a little courage.

"Teens are spending more and more time on screened devices and sleep complaints are common in this age group," Stenvers said in presenting his summary at the European Society's meeting. endocrinology in Lyon, France, Sunday. "Here we show very simply that these sleep disorders can be easily solved by minimizing the use of the evening screen or exposure to blue light."

Stenvers' trial lasted five weeks, during which he conducted an experiment on 55 Dutch teens: 25 "frequent users of screens", who used devices for four hours or more per day, and 30 infrequent users, who impressively only used screens for about an hour a day. During this period, each group of teenagers (who lived at home and not in a laboratory) tidied up their screens at night all week, then, after a week off, had the opportunity to use orange-style Guy Fieri. – Blue light protection goggles to block harmful rays.

On average, frequent users of the screen took 30 minutes longer to fall asleep and also reported more disturbances during the night. But after six nights of no use of the screen or orange glasses, their sleep patterns began to look more like those of frequent non-users of the screen.

In short, their detoxification of blue light seemed to work.

light blue sleep
The blue light of tablet, laptop and phone screens can disrupt the circadian rhythm and make sleep more difficult.

When frequent users wore the glasses or abstained from screens, they fell asleep 20 minutes faster and woke up 20 minutes later on average. "Both interventions have restored the sleep times of frequent users around those of occasional users," note the authors in their summary.

The effectiveness of these solutions, they add, could result from melatonin – the sleep-related hormone that soars towards bedtime but is inhibited by exposure to the blue light. In the absence of abstinence from the evening screen, he finds that orange glasses can help stop the effects of melatonin suppression of light. This discovery echoes previous tests on blue light filters and is part of the idea of ​​Apple's Night Shift mode.

Although Stenvers states that these simple interventions have made it easy to reverse sleep loss, total screen abstention for a week requires a unique type of mental strength. In reality, it is probably not possible for people who work in the computer or watch Game of thrones at 9 pm. every Sunday and fall asleep with a new dose of new possible endings in their minds.

But if you can get up to watch King's Landing burn through the orange hue of a blue light blocker, your sleep could be a lot more peaceful – even if you do not get away from the screen .

Partial summary:

The methods: We identified frequent screen users (use? 4 hours a day, n = 25) and infrequent screen users (use? 1 hour a day, n = 30) among Dutch teenagers? 12 to 17 years old. In a 5-week randomized controlled crossover trial, frequent screening users were evaluated for 3 evening interventions of one week each, with 1 week wash periods: 1) when using usual screening; 2) wearing anti-blue light glasses; 3) by refraining completely from the use of the screen. In a case-control sub-study, infrequent screening users were evaluated for one week. During each measurement week, sleep was assessed with the help of sleep and actigraphy diaries, and the onset of melatonin was evaluated with the help of a saliva sampling at home 30 minutes on the last evening of each week of intervention. The tests were recorded under the names NTR6712 (RCT) and NTR6722 (case-control).

Results: In frequent users of screens, anti-blue light glasses and the abstention of the use of the screen induced a point of sleep earlier than the usual use of the screen. Both interventions restored the sleep times of frequent users around those of infrequent users. In many subjects, it was difficult to identify a clear start of melatonin, but the blue light blocking glasses reduced the absolute melatonin levels compared with the usual use of a screen.

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