Life Style

“Teenagers should be more aware of this”: young people’s sleep, a public health issue

During the week, Gaspard, 17, goes to bed “at 11:30 p.m.”. After dinner he “finishes (his) homework “ where “relax” by watching videos, series or by going on social networks. “I often stay on my phone until bedtime. But at night, I turn it off,” assures this terminal student.

The next morning, the young Parisian gets up “at 7:45 a.m.” to go to high school “at 8:10 a.m.”. “I delay getting up as much as possiblebut I don’t have too much trouble waking up,” he said. Gaspard sleeps “between half past seven and half past eight”according to his calculations, but he knows that at his age he would have “need to sleep longer”. According to the latest studies, he is not the only one: 88% of 15-24 year olds say they lack sleep, according to the National Institute of Sleep and Vigilance (INSV).

→ READ. Young people’s lack of sleep worries health professionals

The needs vary, of course, from one individual to another but, in adolescence, “they are still very high”, observes Marie-Françoise Vecchierini, neurologist and psychiatrist, specialist in sleep pathologies. “At this age, young people should sleep between eight and ten hours. Most don’t, as the weekend sleep rebound shows. »

Teens feel less sleep pressure

All ages of adolescence are concerned: 27% of those under 15 “sleep two hours less per night during school time compared to rest days”,“44% go to bed after 10 p.m. on weekdays and 10% sleep seven hours or less,” according to a survey by Réseau Morphée conducted among secondary school students in the Ile-de-France region.

These results come as no surprise to Anthony, father of a 14-year-old teenager: “At home, it’s not the fight to send him to bed but it’s generally complicated, he acknowledges. You have to repeat it to him several times in the evening, when he says himself that he is tired. »

MAINTENANCE. In children and adolescents, “sleep helps to consolidate knowledge”

Not wanting to go to bed is normal at this age. It’s even physiological. Teenagers feel less sleep pressure. They have less desire to go to bed and more difficulty falling asleep, emphasizes Marie-Françoise Vecchierini. In addition, they have a tendency to evening, that is to say, they go to bed and get up late. » Professor Claude Gronfier, chronobiologist at Inserm, talks about“maturing biological clock”.“The oscillation of this internal clock is slower, and this slowing delays falling asleep. »

The living environment can also have an impact on sleep, when the teenager shares his room with a brother or sister, for example. But it is especially the evening activities on the screens that prevent young people from sleeping. “After dinner, 52.6% of college students spend more than an hour in front of a screen, and 18.8%, more than two hours”, according to the Morpheus Network survey. More and more teenagers are even using their smartphones at night to ” send text messages ” (15%) and connect to a social network » (11%). Some take advantage of “spontaneous awakening” (73.9%), “but 21.6% organize it from bedtime, with 10.6% who plan to wake up during the night”.

They are very sensitive to blue light from screens.

The use of screens in the evening is particularly deleterious, recalls Professor Claude Gronfier. “Adolescents have a very heightened sensitivity to light and in particular to light rich in blue wavelengths given off by screens, because their lens is still very transparent”, he explains. However, this type of light has the effect of further delaying the biological clock when exposed to it before bedtime. »

The screens are not the only ones responsible, according to the specialist. All sources of artificial light are concerned. Their effect is all the greater when young people are less exposed to natural sunlight, as they are less often outdoors.

→ ARCHIVE. Do sleep and screens go hand in hand?

Psychological factors sometimes also disturb their sleep. “With the pandemic and now the war in Ukraine, teenagers no longer trust adults too much to create a quiet world, and this causes a lot of anxiety.analyzes Marie-Rose Moro, child psychiatrist, director of the Maison de Solenn. At this age, they are particularly vulnerable to these worries. »

Christelle, a teacher in the Paris suburbs, also notes a “significant increase in anxiety” in his students “about their professional future”. This has been particularly noticeable over the past two or three years, she says. With the reform of the baccalaureate, they have to make choices earlier and earlier, and this worries them a lot. Some tell me that they have trouble sleeping and I can see that. Just this morning, one of my students dozed off during a written test. »

Lack of sleep decreases the volume of gray matter

The phenomenon does not only affect high school students: 30% of middle school students questioned by the Morpheus Network recognize that “Getting up is extremely difficult on school days” and “23% are drowsy or fall asleep in class”. Consultations “related to the use of screens and delayed sleep” moreover have “increased slightly in recent years”according to Dr. Ali Ahmad Rabih, head of the sleep department at Toulon hospital.

Sleep, parents try to frame

The fatigue of adolescents becomes chronic and ends up having consequences on their cognitive performance. Lack of sleep leads to a drop in school results, warns Stéphanie Mazza, professor of neuropsychology. And even a decrease in the volume of the gray matter of the brain, according to a study by Inserm. The later young people go to bed at the weekend, the more this volume decreases, the researchers note. Sleeping in to compensate for the sleep debt is also not a good idea because this delay further delays falling asleep the following days.

→ READ. Lack of sleep alters teen brains

Another immediate consequence: “the risk of accidents, especially for those who go to school on two-wheelers, and behavioral problems, with less effective management of emotions, notes Marie-Françoise Vecchierini. In the longer term, lack of sleep can also promote depression, overweight or lead to lower immunity and cardiovascular problems. »

How to Help Teenagers Sleep

In short, the finding is alarming, and specialists today speak of a real public health problem. “Unfortunately, we do not know enough, deplores Claude Gronfier. Teenagers should be more aware of this, parents should be better informed and national education should take up the issue, because we have the means to act. » Professionals therefore recommend a “digital curfew” at least one hour before bedtime, no television in the bedroom, physical activity, especially in the morning, ventilation of the room, reserving the bed for sleep and avoiding energy drinks.

According to the chronobiologist, “the most effective way to synchronize the internal clock is to be exposed to natural light as soon as you wake up, by opening the shutters as soon as possible, he advises. Inwinter, you can also use a phototherapy lamp during breakfast. » Like other specialists, Claude Gronfier also proposes to delay the start time of classes. “Asking a teenager to be in school at 8 a.m. is like asking an adult to go to work at 6 a.m.,” he compares.

→ IN THE NEWS. Since the Covid, children spend even more time in front of screens

Anthony, father of three children, would be rather favorable to it, because he sees well that his teenager “has trouble getting up at 7 o’clock”, but he fears that this discrepancy “doesn’t force you to finish school too late and don’t delay bedtime again”.

However, an American study has shown that “starting class fifty minutes later only shifted bedtime the day before by ten to fifteen minutes, emphasizes Claude Gronfier. Not only did the children not go to bed much later, but they gained thirty-five to forty minutes of sleep per night. » Which is not negligible.


The stages of sleep

Falling asleep is followed by a phase of light sleep, which leads in about twenty minutes to deep slow sleep. During this stage, which is characterized on the electroencephalogram by slow and ample waves, it is difficult to wake the sleeper. After about ninety minutes, REM sleep appears. There, the cerebral activity is intense, quite close to that of awakening, but the body is inert.

These different stages constitute the first cycle of sleep. A cycle lasts about ninety to one hundred minutes. A night has four to six cycles. The first half of sleep is rich in deep slow-wave sleep, while the second half is essentially made up of the alternation of light sleep and paradoxical sleep.

Source: Morpheus Network


Where to get information?

The National Institute of Sleep and Vigilance (INSV) offers content on the sleep of children and adolescents on its site, with videos, brochures to download and questionnaires to help parents assess possible problems. Families will also find information on the screens, as well as the ten recommendations from doctors. Website:

The Morpheus Network, a health network in the Ile-de-France that brings together professionals involved in the management of sleep disorders, also offers very comprehensive content on the sleep of young people aged 0 to 18 with, as a bonus, a forum led by specialists.

Where to consult?

First you need to go to the pediatrician or family doctor. Depending on the disorder, the latter may refer the adolescent to a center dedicated to the exploration of sleep and its pathologies, approved by the French Society for Sleep Research and Medicine (SFRMS). These structures bring together specialists and allow more in-depth examinations to be carried out.

To read

What’s new in sleep?by Anne Le Pennec and Sylvie Royant-Parola, Éditions Quae, 2018, 192 p., €19.

This book, intended for the general public, takes stock of sleep, its mechanisms and its effects.
on health, with practical advice to better preserve and improve it, whatever the age.


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