We all know we need at least some sleep – but how little can we actually get away with?
Obviously, you need much more sleep when you’re a child compared to a fully-grown adult.
As UK’s Sleep Charity says, while the average amount of sleep an adult needs is around eight hours a night, there is no “normal” length of time.
Some people claim to be able to cope on as little as five hours of sleep though, including former US president Barack Obama, former UK PM Margaret Thatcher or and even Rihanna.
Is it possible to function on such little sleep, consistently?
Yes – but only for a handful of people who have ‘Short Sleeper Syndrome’.
It’s generally defined as people who sleeps for just a few hours each night, without experiencing any of the difficult side-effects the following day (we’re talking sleepiness, low mood and general exhaustion).
The US firm, the Sleep Foundation, says this means their bodies cope with six hours or less of sleep per night, even when the individual has more time available to sleep.
How do you become a short sleeper?
If you’re thinking you can just hack your body’s need to sleep, you’re out of luck.
Behavioural neuroscientist Andrew Coogan told news website Live Science that: “True short sleeper syndrome is probably a genetically determined trait.
“There have been studies identifying genes implicated in families in which short sleeper syndrome runs.”
Previous studies pointed to a particular gene variant which resisted sleep deprivations, while not cutting back on non-rapid eye movement sleep – the stage which is important for physical recovery and memory consolidation.
The 2019 study published in the science journal Neuron suggested that “in the human population this a rare mutation, with an incidence of 4.028 out of 100,000.”
That means you having short sleeper syndrome is pretty small – less than 1%.
In fact, Coogan suggested that most people who think they’re short sleepers “have just become accustomed to a life that doesn’t feature much sleep”.
“These people might be able to do it for certain times of their life, but not across their entire lifespan,” he speculated.
How do you know if you’re actually a short sleeper?
Coogan said: “There is no specific test, but a good rule of thumb is that, if on the weekend someone’s sleep duration does not get longer, despite having the opportunity to sleep in, then they may be a true short sleeper.”
Does it matter if you sleep less, but you’re not a short sleeper?
As an adult, you’re supposed to get between seven and nine hours of sleep, although this can fluctuate throughout someone’s lifetime according to other factors.
And sleep is important, for cognitive function, repairing your body and to your general wellbeing as we all know, so it is important to give yourself time to sleep.
But, the odd sleepless night is OK.
In fact, the Insomnia Clinic explains: “Your body knows what to do. If you have a bad night’s sleep one night, as long as you don’t then take steps to amplify this issue, you’ll have built up a great ‘sleep drive’ for the following night.”
Your ‘sleep drive’ is defined as your appetite for sleep, so even if you’ve slept badly the night before, you should still be able to follow the same routine the next day – and then you’ll be able to return to your normal sleep pattern.