WAKE UP! It’s bedtime
Margaret Thatcher claimed she could get away with just four hours’ sleep a night. Thomas Edison thought time spent in bed was time wasted. Donald Trump argued that sticking to three hours a night while on the presidential campaign trail kept him ahead of the competition.
It is a source of pride for many that they can get by on so few hours’ slumber. Yet ask the neurologist Matthew Walker what percentage of the population can function happily and healthily in this way and his answer is: zero.
Walker says: ‘Sixty years of scientific research prevent me from accepting anyone who tells me that he or she can get by on just four or five hours of sleep a night just fine. We need eight. A lack of sleep doesn’t just make you groggy – it’s a slow form of self-euthanasia.’
Why We Sleep is the scientist’s answer to Arianna Huffington’s The Sleep Revolution. The need to sleep is one of our basic biological drives, yet our 24-hour, 21st-century life has wholly neglected its importance.
We are in the middle of ‘a sleep-loss epidemic’ and Walker, the director of the Sleep and Neuroimaging Laboratory at the University of California, Berkeley, is determined to wake us from this nightmare. It doesn’t take much to disrupt the circadian rhythm – our 24hour internal clock – and ruin our sleep cycles: children, jet-lag, insomnia, work pressure, alcohol and caffeine (which, I learned, has a half-life of about five to seven hours) all work against us.
But we aren’t fully aware of the many damaging side-effects sleep loss has on us. They range from overeating (those with sleep deprivation eat, on average, 300 calories more a day than they need), to exacerbating psychiatric and neurological conditions, from bipolar disorder to Alzheimer’s. Then there are the increased risks of physiological disorders and diseases.
People aged 45 and above who sleep fewer than six hours a night are twice as likely to have a heart attack or stroke, compared to those sleeping seven or eight hours a night – a sleepdeprived heart beats faster. And we haven’t even got on to the car crashes caused by momentary lapses in attention.
Even minor changes to our sleeping patterns have huge effects. ‘In the Northern Hemisphere, the switch to daylight saving time in March results in most people losing an hour of sleep opportunity.
Should you tabulate millions of daily hospital records, as researchers have done, you discover that this seemingly trivial sleep reduction comes with a frightening spike in heart attacks the following day.’ The opposite is true, too: come autumn, the rates of heart attacks plummet the day after the clocks go back.
And yet, when was the last time a doctor prescribed sleep itself? In interviews, Walker claims that sleep costs economies billions a year in lost revenue and advocates the instituting of policies to mandate or encourage sleep. While the sentiment is admirable, I can’t see mandated bedtimes for grown-ups taking off.
And that is the downside to this otherwise fascinating book. The conclusions are rather lofty. Neither a detailed discussion of amyloid deposits or a vision for ‘sleep credit systems’ in the workplace help the insomniac at 3am.
Yet this is a minor quibble in an eye-opening and absorbing book about the science of sleep, which kept this reader up well after her bedtime.
‘What percentage of us can live happily and healthily on a few hours? The answer is zero’