The incredible power of the nap to help us control our emotions

When her daughter was in kindergarten, Rebecca Spencer experienced something that many parents and caretakers know well: the power of a nap.

Without a nap, her daughter was at the same time dazed, grouchy or both at the same time.

Spencer, neuroscientist specialized in sleep at the University of Mbadachusetts in Amherst, United States, wanted to investigate what lies behind this anecdotal experience.

"Many people realize that a child without a nap is emotionally deregulated," he explains. "This led us to ask ourselves a question:" Do naps really help to deal with emotions? "

• Eight things to know about sleep and its effects on the body

Scientific research has already shown that in general, the dream helps us understand emotions. In fact, it plays a key role in encoding information extracted from the day's experiences, so it's essential to preserve the memories.

And emotional memories are unique because of the way they activate the amygdala: The emotional heart of the brain

"The activation of the amygdala is what allows you to remember the day of your wedding and your parents' funeral more than any other day of work, "said Spencer.

The body of the amygdala attributes to these memories a meaning, so that they are treated longer during sleep and are repeated longer than other trivial memories.

As a result, emotionally significant memories are easier to retrieve in the future .

Researchers are discovering in sleep laboratories how a nap can even improve the emotional experiences we are.

But having an influence on the way memories are treated, the dream can also change their power.

"The dream is particularly effective at transforming emotional memory," says Elaina. Bolinger, specialist of emotion and sleep at the University of Tuebingen, Germany

In a recent study, Bolinger and his colleagues showed both negative and neutral images to children of 8 at the age of 11. The children showed their emotional reaction by choosing simple drawings representing people.

• 5 tips to sleep well, long and deep

Then some children slept and others no. The researchers controlled the physiology of their brain through electrodes located in the next room

The next morning, the children saw the same pictures, as well as new ones. And compared to the children who stayed awake, the children who had slept controlled their emotional responses better.

This research suggests that sleep helps crystallize emotional information and control how we feel. And this effect occurs quickly.

Sleep helps children control their emotional response.

"Much of the current research indicates that there is only one night's sleep and it's useful," Bolinger says. "It's useful for the treatment of memories, but also for emotional regulation in general."

But all sleep is not the same.

Types of Sleep

Sleep with fast-moving movement badociated with emotional memories, and having more REM sleep makes people better evaluate others' intentions and remember emotional stories

theory, the stress hormone, norepinephrine, would be absent during REM sleep. Temporarily released from this hormone, the brain can process memories without stress.

• The curious experience of lucid dreams: can you control what you do while you sleep?

Simon Durrant, head of the sleep and cognition laboratory at the University of Lincoln, England, stresses another aspect.

The prefrontal cortex is the most developed part of the brain: this is where, says Durrant, "the human impulse to remain calm and not to react immediately to things"

On awakening, it is the part that keeps the body of the amygdala under control and, therefore, the emotions. This relationship is reduced during sleep. "19659003]" In a sense, emotion is endemic during REM sleep. "

• Why do we dream and why do dreams repeat themselves?"

But Spencer believes that non-REM sleep also plays an important role.Slow sleep (SWS) is the first phase of sleep that consolidates memories and is particularly effective for the processing of neutral memories.

Spencer's research suggests that the amount of SWS activity during sleep affects the way emotional memories are transformed.

Naps are mainly in non-REM sleep, and a recent article co-written by Spencer seems to be the first to show that naps, not just night-time sleep, contribute to the treatment of emotional memory in children.

Without a nap, the children were emotionally biased, and with the nap they responded in the same way to neutral stimuli and emotional stimuli.

In summary, he sure that "if they do not nap, children become hypersensitive to emotional stimuli" because they did not consolidate the emotional burden of that day

Even a nap, which has no paradoxical sleep, helps children regulate their emotions.

Spencer thinks the nap also contributes to the treatment of emotions in the adult, but not to the same extent. An adult has a more mature hippocampus and, therefore, a greater ability to preserve his memories. Do not sleep does not hurt them too much

However, it is only up to a certain point. Spencer's research on aging suggests that "we need to consolidate memories more often as we get older"

It's worth noting that older adults show a bias for memories positive, while young adults tend towards negatives.

• The less you sleep, the shorter your life will be

This may be explained by the fact that children and adolescents focus on negative experiences because they contain essential information to learn: dangers of fire at the risks of accepting a drink from a stranger.

But towards the end of life, people give priority to the positive. They also have less paradoxical sleep, the type of sleep that will save the most negative memories, especially in people with depression.

Therapeutic Uses

Sleep researchers also badyze the potential of certain facets of sleep to treat sleep disorders. Post Traumatic Stress Disorder (PTSD).

One study suggests that sleeping within 24 hours of a traumatic experience makes these memories less distressing in recent days. Sleep therapy can help people with anxiety to remember that they have eliminated their fear.

Researchers have discovered that REM sleep can help us process memories.

Conversely, sleep therapy, in which people are deliberately deprived of sleep, is spreading as a method of treating depression.

In some cases, insomnia can have a protective effect. Spencer points out that after a trauma, "the natural biological response in these conditions is to suffer from insomnia"

Thus, it can sometimes be helpful that the lack of REM sleep alters the brain's ability to consolidate emotional memories.

• ] The Sleep Home Test to Find Out if You Sleep a Little

"There is evidence that people who sleep longer tend to be more depressed," says Durrant. The expert thinks that's because a subgroup of depressed people is restoring their negative memories during REM sleep.

"I do not think I'll be able to solve this problem," he says of all the potential clinical applications of sleep therapy and wakefulness.

But it is clear that some types of decision-making improve after sleep, partly because of the way sleep regulates all this whirlwind of feelings.

Bolinger explains clearly: in general, "sleep helps you feel better."

In the end, the best recipe for a broken heart or a troubled mind can be a nap.

Read the original story in English on BBC Future