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IELTS Reading Practice Test - Sleep should be prescribed: what those late nights out could be costing you
Sleep should be prescribed: what those late nights out could be costing you
Leading neuroscientist Matthew Walker on why sleep deprivation is bad for us - and what you can do about it
A
A. Matthew Walker dreads the question 'What do you do?' On an aeroplane it usually means that while everyone else watches movies, he will find himself giving a talk for the benefit of passengers and crew alike. To be specific, Walker is the director of the Center for Human Sleep Science at the University of California. No wonder people long for his advice. As the line between work and leisure grows more blurred, rare is the person who doesn't worry about their sleep. Indeed, it's Walker's conviction that we are in the midst of a 'catastrophic sleep-loss epidemic. He has now written Why We Sleep, the idea being that once people know of the powerful links between sleep loss and poor health, they will try harder to get the recommended eight hours a night. Sleep deprivation constitutes anything less than seven. ‘No one is doing anything about it but things have to change. But when did you ever see a national health service poster urging sleep on people? When did a doctor prescribe, not sleeping pills, but sleep itself? It needs to be prioritised.’
B
B. Why are we so sleep-deprived in this century? In 1942, less than 8% of the population was trying to survive on six hours or less sleep a night; in 2017, almost one in two people is. Some reasons are obvious, but Walker believes, too, that in the developed world sleep is strongly associated with weakness. ‘We want to seem busy, and one way we express that is by proclaiming how little sleep we're getting. When I give lectures, people wait behind until there is no one around and then tell me quietly: "I seem to be one of those people who need eight or nine hours' sleep." It's embarrassing to say it in public.’
C
C. Walker has found clear evidence that without sleep, there is low energy and disease, and with sleep, there is vitality and health. More than 20 studies all report the same relationship: the shorter your sleep, the shorter your life. For example, adults aged 45 years or older who sleep less than six hours a night are 200% more likely to have a heart attack, as compared with those sleeping seven or eight. This is because even one night of sleep reduction will affect a person's heart and significantly increase their blood pressure as a result. Walker also points out that when your sleep becomes short, you are susceptible to weight gain. Among the reasons for this are the fact that inadequate sleep increases levels of the hunger-signalling hormone, ghrelin. ‘I'm not going to say that the obesity crisis is caused by the sleep-loss epidemic alone says Walker. However, processed food and sedentary lifestyles do not adequately explain its rise. It's now clear that sleep is that third ingredient.’
D
D. Sleep also has a powerful effect on the immune system, which is why, when we have flu, our first instinct is to go to bed. If you are tired, you are more likely to get sick. The well-rested also respond better to the flu vaccine so this is something people should bear in mind before visiting their doctors. Walker's book also includes a long section on dreams. Here he details the various ways in which deep sleep - the part when we begin to dream - helps us deal with our emotional experiences. He points to how important deep sleep is to young children. If they don't get enough, managing aggressive behaviour becomes harder and harder. Does Walker take his own advice when it comes to sleep? ‘Yes. I give myself a non-negotiable eight-hour sleep opportunity every night, and I keep very regular hours. I take my sleep incredibly seriously because I have seen the evidence.’
E
E. Sleep research shows that we sleep in 90-minute cycles, and it's only towards the end of each that we go into deep sleep. Each cycle comprises of NREM sleep (non-rapid eye movement sleep), followed by REM (rapid eye movement) sleep. ‘During NREM sleep ... your body settles into this lovely low state of energy,’ Walker explains. ‘REM sleep, on the other hand is ... an incredibly active brain state. Your heart and nervous system go through spurts of activity.’ Because we need four or five of these cycles to stay healthy, it's important for people to break bad sleep habits. For example, they should not be regularly working late into the night as this affects cognitive functioning. Depending on sleeping pills is also not a good idea, as it can have a damaging effect on memory.
F
F. So what can individuals do to ensure they get the right amount of sleep? Firstly, we could think about getting ready for sleep in the same way we prepare for the end of a workout - say, on a spin bike. ‘People use alarms to wake up,’ Walker says. ‘So why don't we have a bedtime alarm to tell us we've got half an hour, that we should start cycling down?’ Companies should think about rewarding sleep. Productivity will rise and motivation will be improved. We can also systematically measure our sleep by using personal tracking devices, Walker says, and points out that some far-sighted companies in the US already give employees time off if they get enough of it. While some researchers recommend banning digital devices from the bedroom because of their effect on the sleep-inducing hormone melatonin, Walker believes that technology will eventually be an aid to sleep, as it helps us discover more about the way we function.
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a comparison between two different types of sleep that people experience
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