When we talk about sleep, it’s an hours game – how many of them do we get a night? Popular wisdom holds that you need eight hours of unbroken sleep to properly function; substantially less can damage your health. Hence the obsession with sleep-tracking gadgets, and maximising time in bed for (so the theory goes) maximum restfulness.
These efforts might be misplaced. The eight-hour rule is, as psychologist and sleep therapist Merijn van de Laar explains in his new book, How to Sleep Like a Caveman: Ancient Wisdom for a Better Night’s Rest, an arbitrary number invented during the Industrial Revolution. Driven by his own experience of insomnia, van de Laar examined how humans slept in their earliest state, with the help of research done on the Hadza, a Tanzanian tribe that still live as hunter-gatherers.
Van de Laar told GQ about how the first steps towards better sleep involve rejecting the eight-hour standard and accepting that waking up during the night is completely natural. He also explained that for insomniacs, restricting your time in bed can be a counterintuitive but very effective treatment.
What inspired the book?
I had sleep problems myself for three years – insomnia when I was 28 to 31 – and I found that there was a lot of information coming from social media, from media in general, that was really hampering my sleep; messages like, ‘You have to sleep for eight hours without any interruptions.’ I thought, ‘Well, this might be our Western view, but how do other people sleep? And what is the biological basis?’ So I started diving into the research on tribes like the Hadza.
So how did cavemen sleep, and contemporary tribes sleep now?
They’re in bed for over nine hours. If you look at Western sleep, we’re in bed for seven-and-a-half, eight-ish [hours]. But they sleep for 6.2 to 6.5 hours; [no] more than we do on average. They’re awake for over two hours on average each night, but they don’t report any sleep problems – [it’s] part of the night. The second thing [the tribes do is] wind down before bed. They sit around a campfire [and] chat; it’s dark, and they have the natural temperature decrease that prepares our bodies for sleep. In modern Western society, we’re really focused on [falling asleep] fast and without any interruptions.
When did the eight-hour rule come in?
The Industrial Revolution. People went to bed later because of artificial light, and there were long working hours. Robert Owen, a [British] social reformer, said, “This has to stop. You have to sleep for eight hours, rest for eight hours and work for eight hours.” Owen was not a sleep scientist, [but] it sounds nice and balanced, and everybody started repeating [it]. Eight [hours] is actually quite high. Only 15 to 25% of people reach eight hours or more, and that’s been quite stable for the past 50 years.
Is there any evidence that sleeping for eight hours has any health benefits?
Research shows that people who sleep around seven [hours] actually have the best benefit; they die later than people sleeping [fewer] or more. That doesn’t mean there’s a causal relationship, because there might be many circumstances explaining this. But if you look at population data, you see that people who sleep for eight hours actually die just as soon as people who sleep for five and a half.
How should we change our attitude?
Lower your expectations. If you sleep for six hours and you’re awake for one hour on average during the night, that [isn’t] a problem. Being awake for 20% of your time in bed is actually quite normal. But it is a problem if you’re awake and stressed out. There has been an increase in insomnia the past couple of years because strict rules around sleep [lead to anxiety]. It’s good for people to know that only a very small group sleeps eight hours without interruptions. A lot of people look at the alarm clock during the night – they try to see what time it is and start to count how many hours they still have. That also has a very negative effect.