It can be a temporary abandonment, a padded parenthesis, or a discreet snooze in the middle of the day. Whether wanted or necessary, the siesta is increasingly seen as a solution to the lack of sleep of the French. “A third of working people in France are below the 6-hour sleep per 24-hour mark, which makes them more at risk for a whole host of pathologies”, warns Brice Faraut, neuroscience researcher at the Sleep and Vigilance Center of the Hôtel-Dieu (University of Paris Descartes-APHP). As a result, a good portion of these workers try to make up for their sleep debt by sleeping more on weekends. “But this can create a social jet-lag”, a discrepancy between the rhythm of life and the biological clock, assures the neuroscientist, author of Saved by the siesta (Actes Sud), and fervent defender of this mode of slumber.
The nap, when done well, can then be likened to a form of miniature night’s sleep. Sleep is divided into phases, each time with different effects on the body. One in particular is the reduction of stress and its deleterious effects on the body. “As soon as you fall asleep, all the hormonal mediators of the stress systems drop, this break is very beneficial, from a cardiovascular point of view”, explains Brice Faraut.
The other benefit of sleep is to participate in the release of essential hormones. Thus it is when we sleep, during the slow deep sleep phase, that our body produces the majority of growth hormones, essential to allow children to grow, but just as essential to adults to promote cell regeneration, and the maintenance of our joints. And for that, a long night is not necessarily necessary. “During a one-hour nap, it is possible to have 30 minutes of deep slow sleep, a phase of sleep which is very regenerative at this level”, assures Brice Faraut.
Case-by-case naps
To recover a little vigilance, and activate certain functions, a few minutes may be enough. Several studies have shown that short naps (5 to 20 minutes) can significantly improve alertness, immediately for the shortest ones, and in the few minutes following sleep for those lasting several minutes. In 1995, NASA even revealed in a study that the “ideal” duration of the nap was 26 minutes. The American space agency had thus determined that the “performance” of the subjects tested (ie reaction time and memory) had improved by 34% and “alertness” improved by 54%.
Could the nap therefore replace the sleep of the night? Unfortunately for night owls, the answer is not so simple. “The ideal is always to sleep during the night as many hours as you need, and the nap can remedy this deficiency, but it should not be a solution to counter a chronic lack of sleep”, nuance Brice Faraut. Not everyone should indulge in a daytime nap, though. In the case of treatment of insomnia by cognitive and behavioral therapies, the use of a nap is not even recommended, because it can reduce the pressure of sleep and therefore accentuate the difficulty in falling asleep at bedtime. “It can be a very bad idea in case of insomnia”, confirms Renaud Tamisier, the president of the scientific council of the French Society for research and sleep medicine. “The nap can be harmful as well as beneficial and this complexity needs to be taught”, he pleads.
Brice Faraut even assures that one can become a professional siesta. This is not a Gaston Lagaffe, whose job is largely to pitch down at work, but to train his body and his mind to take a nap. A rhythm of the biological clock which is acquired gradually, thanks to a good psychological conditioning. “The more you practice, the easier it will be to fall asleep, and people who do this regularly wake up on their own.” Thus a study by the University of Pennsylvania dating from 1977 showed that nappers who practiced it by “taste” (and therefore regularly), fell asleep in 14 minutes, when it took nearly double (26 minutes), for non-nappers join Morpheus.
“Promote attention to one’s pleasure in being asleep”
Often, would-be nappers are put off by the sensation upon waking. The perception of waking up more tired than going to bed is called “sleep inertia” by specialists. It involves drowsiness, and a decrease in performance immediately after waking from a nap. A post-nap effect to be taken into consideration if the latter takes place just before returning to work, and which can be compensated by taking a coffee just before going to bed, the caffeine taking effect after a twenty minutes.
Still relatively marginal, could the siesta prevail in France? According to a survey conducted by Public Health France in 2019, more than a quarter of adults take at least one nap on weekdays, and just over 30% of French people take a nap of around an hour on weekends. Yet in companies, the practice remains associated with a form of laziness, idleness. Under the impetus of start-ups, some companies are planning rest areas. Sometimes with the idea that a “power nap” (a quick nap) can improve employee productivity. “The idea of a nap place in companies is good, not for recovery, but rather to make workers attentive to their sleep time”, insists Jean-Arthur Micoulaud-Franchi, lecturer and hospital practitioner in neurophysiology at the University of Bordeaux. For this doctor “to promote the nap is to promote attention to the pleasure of being asleep, and therefore attentive to our physiological needs”.