Getting a good night’s sleep – or not

Review: Vivien Horler
Why We Sleep – the new science of sleep and dreams, by Matthew Walker (Penguin Books)
How do you know if you’re routinely getting enough sleep? There are two simple questions, says neuroscientist Matthew Walker: are you sleepy around 11am, and can you function before noon without a cup of coffee?
If you answer yes, and no, Walker says the chances are you’re not, along with most people in the Western world. Left to ourselves, without outside pressures such as starting school or work early, and staying up late for a myriad reasons, the average person would be awake for about 16 hours and sleep for eight in every 24-hour period.
But for various reasons, including inappropriately early school start times, bosses’ expectations that employees will be available on email late into the evenings, sleep-destroying blue-light screens and a general discounting of the importance of sleep, most of us do not get as much as we need.
This, says Walker, lays us open to almost every malady known to humankind, from obesity to diabetes, insomnia, Alzheimer’s, cardiovascular disease, cancer, anxiety, depression and the failure of children to live up to their potential. If there were a single drug that could mitigate against these dreadful conditions, we’d be clamouring for it. Yet sleep protects against all these conditions, and it’s freely available.
Walker says he has always found it curious that Margaret Thatcher and Ronald Reagan, two heads of state vocal about sleeping only four to five hours a night, both went on to develop Alzheimer’s.
And he adds: “The current US president, Donald Trump – also a vociferous proclaimer of sleeping just a few hours each night – may want to take note.”
British-born Walker, who has held chairs in psychiatry, neuroscience and psychology at Harvard Medical School and the University of California, Berkeley, has studied sleep for the past quarter century. He has been a sleep consultant to the US’s National Basketball Association and National Football League, Britain’s Premier League, Pixar Animation, and US government agencies as well as technical and financial companies.
There is a wealth of fascinating detail in this book. Walker tells us we are governed by circadian rhythms, which see to it that a couple of hours after sunset we start to feel sleepy, thanks to the release of the hormone melatonin, which signals to our body that bedtime is approaching.
But melatonin doesn’t put us to sleep – that’s the job of a chemical called adenosine. During our waking day adenosine increases in concentration so that after 12 to 16 hours it will be hard to resist falling asleep. (But if you have an early evening sleep, as many elderly people do when napping in front of the telly, you use up some of your adenosine and then find it hard to fall asleep later.)
We’ve all heard of REM or rapid-eye-movement sleep, which is what happens when we’re dreaming, but an important part of our rest is NREM or non-rapid-eye-movement sleep. Both types perform vital functions for our body and our brain. We tend to start with NREM and then cycle into REM every 90 minutes or so, ending in the last hour or so of the night with REM. The late REM sleep appears to help us consolidate what we learnt the previous day, with Walker quoting a pianist who told him that he would practise intensively, often making the same mistake at the same point. But he found the next morning he was able to play his piece perfectly – somehow during the night his ability had been consolidated.
But this consolidation, says Walker, is missed when people, notably school pupils, have to wake up early. Walker believes schools should not open before 9am.
Much of what Walker has to say is food for thought. The poor effects of caffeine and sleeping pills on sleep are discussed in detail, which made me feel smug as I use neither. But the section on the effects of alcohol were, um, sobering.
Walker argues that the effects of sleep deprivation can mimic the symptoms of various mental ailments including ADHD, and wonders how many restless, sleepy children have been prescribed Ritalin unnecessarily. And on the subject of children, he points out that kids from low-income families are more likely to take public transport to school, meaning they have to get up earlier than those whose parents drive them to school, becoming even more disadvantaged by losing the last cycles of REM sleep.
This book was first published in 2017 so it is not a new book, but I got it as a Christmas present and have found it absolutely riveting. Insomnia increases with age, but I am lucky in that, despite being in my late 60s, I fall asleep with no difficulty. However going back to sleep after the 3am bathroom break can be a challenge.
Walker describes himself as “in love” with sleep, and unlike any other author I’ve come across, wants you to fall asleep while reading his opus. “Knowing what I know about the relationship between sleep and memory, it is the greatest form of flattery for me to know that you … cannot resist the urge to strengthen and thus remember what I am telling you by falling asleep. So please, feel free to ebb and flow into and out of consciousness during this entire book. I will take absolutely no offence. On the contrary, I would be delighted.”

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