The night must last between six and nine hours to be restorative.
The body regenerates during the deep slow-wave sleep phase.
The first three to four hours of the night are the most beneficial.
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Sleep: dive into the arms of Morpheus
“Sleep is more restful before midnight”, “the hours before midnight count double”. Like all old adages, we keep them in the back of our minds, without knowing if they are true. But what about then? Do you really need to go to bed before midnight to be in good shape? We’ll explain it to you.
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What is restful sleep?
Before knowing what time of night it is, you must first understand what restful sleep is. It is “when you wake up in good shape and stay that way throughout the day”explains Dr Pascale Ogrizek, sleep specialist, interviewed by Health Magazine. But to produce this effect, sleep must be long enough, that is to say, last between six and nine hours, depending on each person’s needs and lifestyle. Good quality sleep is also the key to a restful night. This requires having a suitable alternation between the different phases of rest, with deep sleep that is sufficiently long. The regularity of the nights, with fixed bedtimes and getting up times, is also essential.
Please note, however, that each person will react more or less to the application of these concepts. The main thing is that the person wakes up feeling rested and in good shape to face the day.
Deep slow-wave sleep
Each sleep cycle is divided into three phases: light slow-wave sleep, deep slow-wave sleep and paradoxical sleep. Deep slow-wave sleep is the most restorative of the night, because all vital functions are then slowed down. This phase allows you to recover from physical fatigue, since “our metabolism is reduced, our oxygen consumption is lower, our muscle tone is low and all our brain activity is slowed down”, explains Dr Pascale Ogrizek. This is also when the body secretes the most growth hormones, which participate in cell regeneration.
The most restful hours of sleep
The most restorative deep slow-wave sleep occurs in the first three to four hours of the night. Contrary to popular belief, it is not the hours before midnight that are the most beneficial for the body, but the first hours of rest.
However, deep slow-wave sleep will not be as long and restful if you go to bed later than usual, for example at 3 a.m., instead of 10 p.m. Indeed, your biological clock, which knows that your usual waking time is close, will not allow you to plunge into long-term deep slow-wave sleep.
No bedtime is therefore considered the right one. Everyone is free to develop the rhythm that suits them, keeping in mind that six to nine hours of sleep are necessary each night. Researchers from the University of Exeter, in Great Britain, have estimated that the ideal bedtime is between 10 and 11 p.m. since this would reduce the risk of cardiovascular diseases.
