HOW MUCH SLEEP DO YOU REALLY NEED?
There is received wisdom about how many hours a person ‘should’ sleep. (And it’s a popular subject: a quick Google of ‘how much sleep is healthy’ yields 612 million results.)
The oft-quoted magic number is eight hours. Some recently-leaked-but-haven’t-yet-actually-materialized government guidelines were going to suggest we should sleep between seven and nine hours, so an average of eight. The magic number is bandied about like the holy grail. Fail to ‘achieve’ it and you have done just that, failed. Which means you are destined for miserable, exhausted days when you trip over kerbs, crave carbohydrates and can’t work or socialize properly.
This figure hasn’t been pulled out of the air: there have been several studies backing it up. A recent American paper agreed that a minimum of seven hours is recommended for good health. The research was based on hundreds of studies which followed people’s longterm experience of heart disease, diabetes and mental health difficulties. Those who slept between seven and nine hours were typically at lower risk of future ill health, hence the recommendation.
This follows a study in the peer-reviewed scientific journal Sleep. Almost 1.4 million adults were followed by researchers at Warwick Medical School and the University of Naples medical school. The research found that 6 hours’ sleep or less was associated with a 12 per cent increased risk of premature death. Research conducted in a 2019 study had similar results.
The time you need to spend unconscious varies with age. One source detailed that 18–60-year-olds ‘need’ 7 hours or more, 61–64-year-olds ‘need’ 7–9, and the over 65s drop an hour again (for some unspecified reason). ‘Why seven or eight hours seems to be the magic number is unclear,’ said the report’s author. ‘But don’t underestimate the importance of a good night’s sleep.’ Helpful. But. And there is a but. Depending on certain variables, including your genetic make-up, age and lifestyle, your ‘perfect’ amount might fall outside this range. To my sleep guru, Dr Sophie Bostock, this area of research is familiar. ‘Just like your shoe size or height, “optimum sleep” varies from person to person,’ she says. ‘For example, some people have a “short sleep” gene which means they feel alert and refreshed after just five or six hours’ rest.’
Other experts express the view that if you can function on four or five hours a night, can complete tasks and don’t feel tired – well, then you are getting enough.
Donald Trump and Margaret Thatcher both famously claimed they needed only four hours’ sleep to operate effectively (hmm). Sadly, you can’t train yourself to do that. But is it possible to work out your personal magic number, or at least the fewest hours’ sleep you can get away with, and still feel OK?
The answer is apparently to go to sleep when you feel tired and wake up without an alarm. Then do the maths. Says Dr Bostock: ‘If you wake up naturally without an alarm, feel refreshed and don’t need caffeine, sugar or a nap to get through the day, then you’re probably getting enough.’ So perhaps your body decides your own, personal magic number. But 0 hours, 0 minutes is not enough for even the hardiest sleep-warrior.
NOTE: It is apparently possible to sleep for too long. The Warwick and Naples study also found a 30 per cent rise in risk of death for people who slept 9 hours or more, possibly because they may have underlying medical or social problems. Interestingly, the report concluded that while short sleep may represent a cause of ill health, long sleep is believed to represent an indicator of ill health.
