The BBC News World editorial staff
How many hours of sleep per night does a human being need to be healthy? I bet you answered eight hours, but that’s not entirely true according to recent scientific findings.
“It’s a misunderstanding. It’s like saying everyone should be 1.65m. And if you’re shorter than that, you have a problem,” Louis Ptacek, from the university’s neurology department, told the BBC. from California, USA.
We don’t all need the same amount of sleep to feel rested and cope with daily life.
And it’s not a matter of behavior or personal choice. It’s in the genes.
Some people are genetically engineered to naturally sleep fewer hours.
This means that even with only 4 to 6 hours of sleep per night, they wake up rested.
“Some people call them ‘elite sleepers’, and I think that makes sense. They operate on far fewer hours of sleep and do so at a high level. in the working world we live in,” says Dr Ptacek.
Larks and owls
Over the past 25 years, Dr. Ptacek and his team have analyzed the sleep patterns of more than 100 families.
“At the beginning, all our work was focused on the criteria to be used to qualify a person as a night owl.
A person in the advanced sleep phase is often also called a morning lark. He is someone who goes to bed early and wakes up early.
“There are people who have caught our eye. They are extreme morning larks, but they go to bed too late to be part of our criteria.” “It was clear then that some families were morning larks but also night owls,” says Ptacek.
The existence of these people who could only sleep a few hours made the team from the Department of Neurology at the University of California realize that they were dealing with a very different type of condition.
They are sleepers who have a “natural short sleep”, which allows them to get up early but also to go to bed late.
So far, four genes have been linked to “natural short sleep”, but there could be more.
The challenge is that these genes are very rare.
Dr. Ptacek estimates that one in a thousand people are among these “elite sleepers”.
The good news is that they could unlock the secrets of effective sleep for all of us.
Studies conducted by Dr. Ptacek’s team have revealed that these sleepers have a much higher adaptive capacity than other people.
“We have a strong impression that these people are healthier than average,” says the researcher, who adds:
“They sleep a lot less and yet they’re very functional, so – maybe – they sleep more efficiently. The question is what that means.”
We may be closer to the answer to this question.
In a new study, genes associated with “natural short sleep” were introduced into mice with Alzheimer’s disease. And the animals have become more resistant.
“This is very interesting because it suggests that we can use this biological knowledge for therapeutic purposes, not only with regard to neurodegenerative diseases, but also psychiatric diseases, diabetes, obesity and many cancers”, explains Mr. Ptacek.
For the doctor, the study of sleep is like a big puzzle of which we do not yet have the final image:
“We’re still in a process of discovery, trying to find as many pieces of the puzzle as possible. What we have are these families, and within each family we can identify a gene and a genetic variant, and show that those genes are behind those traits.”
For something most of us spend a third of our lives doing, there’s still a lot to understand when it comes to sleep.
“Something happens when we sleep that allows us to restore function and get up the next day to work well. If we can do this better, by understanding how sleep efficiency is regulated, it can have a huge impact. on human health.”