We don’t need so much sleep, says new study
After studies of hunter-gatherer societies, scientists say that we need less sleep than we previously thought. Are we fetishising the time we spend in the land of nod?
In a year the average British person spends 1,460 hours watching TV, 1,000 hours on the internet and 237 hours eating. But none of these dominate our lives in the same way as sleep, which takes up 2,372 hours — around six and a half hours per night.
Conventional wisdom suggests this is not enough. Earlier this year, American charity the National Sleep Foundation said adults under 65 need ‘7-9 hours’ of sleep each night. Oxford academic Dr Paul Keeley recently said Britain has a ‘sleep-deprived society’ and some schools have now begun an experiment in which they stagger their starting times to allow older teenagers to wake up later.
The authors of a new study, though, think these concerns are based on a myth. Scientists in the journal Current Biology wrote that people in preindustrial, hunter-gatherer societies in Tanzania, Namibia and Bolivia only sleep for six hours and 25 minutes per night. Our ancestors, it seems, may not have slept for as long as we thought. Lead author Ghandi Yetish says: ‘There’s this expectation that we should all be sleeping for eight or nine hours a night, and if you took away modern technology, people would be sleeping more. But that’s not true.’ His team’s research is supported by recent studies which suggest eight hours of sleep is more than people need to ensure peak cognitive performance or the lowest mortality rates.
Our need for sleep decreases as we age — newborn babies often spend 18 hours per day asleep — but a survey last year found that 59% of British people were sleep-deprived. This figure had risen by 50% in a year, a trend which has been linked to technology, artificial light, caffeine consumption and stress. Our desperation to fall asleep has inspired a global industry; in the US alone, $32 billion is spent each year on products which help people to drift off, including pills, luxurious mattresses, advice from consultants, ear plugs and eye masks.
Give it a rest
Some say the hours we spend asleep should be no more sacred than any other. Sleep should be treated like other essential activities: eating patterns, for example, have had to fit around our modern lives. We should ignore the scaremongering about sleep, which is designed to convince us to spend more money on products we don’t need.
Spend a day with an insomniac, say others, and you’ll quickly change your mind. We should be very fearful of excuses to cut back on good, regular sleep: it has proven health benefits, recharges our brains and restores our bodies. In an increasingly interconnected and demanding world, sleeping is, if anything, more vital than ever: it is, after all, the only way we can guarantee spending some time alone.
- Do you think you are sleep deprived?
- Do we care too much about sleep?
- Discuss in groups: do you think you get enough sleep? Why, or why not?
- Keep a diary of your sleeping patterns for a fortnight. At the end, review it: are you happy with how much and how well you are sleeping? What explains the consistencies and changes in your sleeping patterns?
Some People Say...
“You get enough sleep when you’re dead.”
What do you think?
Q & A
- Why am I so tired?
- Scientists say that teenagers’ sleeping patterns are very different from those of adults — the NHS says they should get around nine hours of sleep per night. Some studies also suggest that your body clock may be attuned to run later.
- What can I do about it?
- You can develop good sleep hygiene, which means not consuming things which stop you from sleeping near bedtime (products such as caffeine and alcohol have been proven to disturb sleep) or eating large amounts late at night. Develop a bedtime routine and get rid of your screens before settling down — the blue light on them can confuse your brain into thinking it is daytime. Your overall lifestyle matters too — eat healthily and get plenty of exercise, which will tire you out.
- 2,372 hours
- These figures are based on research by the Sleep Council.
- Cognitive performance
- A study in the journal Frontiers in Human Neuroscience found that performance on spatial memory, matching and arithmetic tests was best after about seven hours of sleep.
- Mortality rates
- One study found that women who sleep for more than six and a half hours — or less than five — had higher mortality rates than others. A separate study of cancer patients in the Archives of General Psychiatry found that those sleeping between 6.5 and 7.4 hours a night were the least likely patients to die.
- One study in 2010 found that those aged 66-83 slept for almost an hour less than those aged 20-30.
- 59% of British people
- This research was conducted by Richard Wiseman, professor in the Public Understanding of Psychology at the University of Hertfordshire.
- $32 billion
- This is according to analysis by IMS Health, a US marketing analytics firm. A recent report also suggested that American sleep labs — where people go to have sleep disorders disagnosed — will on their own be worth nearly $10bn by 2020.