Professor Christelle Monaca-Charley and Dr Lise Lanvin explain to us what “normal sleep” is.
- The amount of sleep needed for each individual is very different and is genetically programmed.
- It can therefore vary between less than 6 hours and more than 9 hours.
- During a night there will be 4 to 6 sleep cycles.
“Before discussing pathological sleep, it is important to recall some concepts about normal sleep.” During the Sleep Congress which has just been held in Lille, Professor Christelle Monaca-Charley, neurologist responsible for the sleep disorders unit at the hypersomnia and narcolepsy competence center, as well as Dr Lise Lanvin, vice-president of the French Society for Sleep Research and Medicine (SFRMS), recalled what the classic course of a night was without any particular problems.
What are the stages of normal sleep?
“Sleep is made up of different stages that can be individualized during a polysomnographic recording. Sleep will be differentiated into slow-wave sleep and paradoxical sleep, with distinct modes of regulation,” begin the specialists.
The different stages of sleep are:
– Stage 1 light slow-wave sleep.
– Stage 2 light slow-wave sleep.
– Deep slow-wave sleep.
– Paradoxical sleep.
“These different stages will follow one another to form a sleep cycle, which lasts on average 90 minutes in an adult. Over the course of a night, 4 to 6 sleep cycles will follow one another,” detail the two experts.
Newborns, children, elderly people: what is the duration of normal sleep?
The amount of sleep needed for each individual is very different and is genetically programmed. It can therefore vary between less than 6 hours and more than 9 hours.
“Sleep will also be very different depending on age both in terms of duration and organization,” specify Christelle Monaca-Charley and Lise Lanvin.
Thus, at birth, a newborn will sleep between 16 hours and 18 hours per 24 hours, in a polyphasic manner. During the first months of life, circadian regulation will be put in place to allow the sleep/wake rhythm to be structured.
“Sleep will become mainly nocturnal from the age of three months, and the early afternoon nap will disappear between 4 and 6 years old depending on the child,” continue the doctors. “Gradually, the sleep time over 24 hours will then decrease: 11 hours around the age of 6; 10 hours around the age of 12,” they add.
“With aging, sleep will also change: increase in awakenings, reduction in deep slow-wave sleep, advance of bedtime and wake-up times (i.e. a phase advance of the biological clock)”conclude Christelle Monaca-Charley and Lise Lanvin.
