For most people a good night’s sleep is vitally important, with a big impact on how they perform the following day. But a few claim to be able to function on just a few hours.
Most adults need seven to nine hours sleep per night, while not a hard and fast rule, most people will find themselves feeling tired if they get fewer than five or six hours of sleep per night.
However some well-known people claim to need less than the average. Former U.S. president Barack Obama, for example, admitted to sleeping for as few as five hours per night during his presidency, while former PM Margaret Thatcher, famously said she only needed four hours each night. Elon Musk has claimed he only sleeps six hours per night, between 3am and 9am.
Some experts have suggested that certain individuals could have "short sleeper syndrome", allowing them to feel as rested as other people but with fewer hours of sleep.
"Short sleeper syndrome is experienced by people who normally have short sleep duration during the night but don't suffer any adverse effects of excessive sleepiness, cognitive impairment or lower mood during the day," explained Andrew Coogan, a behavioral neuroscientist at Maynooth University in Ireland.
"That short amount of sleep [six hours or fewer, according to the Sleep Foundation] is sufficient for their own personal physiology."
Unfortunately you cannot train yourself to be a short sleeper, scientists believe it is something genetic that you’re either born with or not.
Several studies have found mutations in specific genes can boost the body's ability to reduce total sleep time while keeping the same amount of important NREM sleep - the non-rapid eye movement sleep that is important for physical recovery and mental consolidation.
However, these mutations are rare, researchers think just 4 people in every 100,000 may have them - and a total of only 50 families with the mutation have so far been found and studied by scientists.
So how do you know whether you’re a short sleeper or if you have just gotten used to sleeping too few hours each night?
For most of us it could be the latter, a 2022 survey by YouGov found that nearly half of people in Britain (49%) think they don't get enough sleep, and only 5% got nine hours or more, on average.
The rule of thumb, say experts is that generally speaking, if you sleep longer on weekends when you don’t have to wake up at a particular time, then your body needs more sleep and you’re not getting enough on weekdays.
Given that true short sleepers are so few and far between, most people who believe they have the condition may in fact be fooling themselves.
"My personal hunch is that the vast majority of people claiming to only need six hours or less of sleep routinely to feel restored — while also remaining fit and well — are not truly short sleepers," Coogan told LiveScience.
“I hypothesize that they have just become accustomed to a life that doesn't feature much sleep. There might be cracks in their theory and they might be shooting themselves in the foot over the longer term. These people might be able to do it for certain times of their life, but not across their entire lifespan like a true naturally short sleeper will do."
