One of the books I read over the Christmas break was ‘Why we Sleep’, by the British neuroscientist Matthew Walker. It only came out a couple of months ago, and it’s all about sleep – why we do it, and why it’s important. Scientific understanding of sleep has come on a long way over the last decade, and this book lays out all the latest thinking. The book is really a shopping list of all the things that can go categorically wrong if you don’t get enough sleep. So how much is enough sleep? It varies a bit, but it is about 8 hours, ranging from 7 to 10 hours. The first myth the book tackles is the belief some people have that they can function perfectly well with less sleep. If you’re the sort of person getting 5 or 6 hours a night, according to Matthew Walker, you are causing yourself serious long-term harm. Sleep is unbelievably important. And most of us are simply not getting enough.


In these passages in the Book of Proverbs (Proverbs 6:1-11), you get something of that old-fashioned attitude towards sleep, an attitude which casts sleep in a negative light. Keep it to a minimum, lest you give way to sloth. Sleep little, and work hard. The passage states that the wise man is he who sleeps little. It reflects something of the protestant work ethic. The man who, despite his meagre beginnings, is able to work hard and make something of himself. The sturdy, responsible individual who is able to triumph despite adversity. Sleeping little is character building. The child is expected to get up early for school, because that’s what being a hard working citizen entails. Because of this cultural attitude towards sleep, most of us have an unconsidered negative bias towards sleep. If we hear, for example, that someone is getting up early and going to gym before work, we’re impressed. We see such routine as a sign of healthy living, despite the fact they’re probably doing themselves more harm than good. Because the bottom line is: if you’re sleeping any less than seven or eight hours a night you are harming yourself.

Mammalian animals all need sleep. There are two types of sleep we all need: non-rapid eye movement sleep, with different degrees of depth, and Rapid Eye Movement sleep (or REM sleep). As you probably know it’s called REM sleep because during REM sleep your eyes dart back and forth. Despite our greater sleep insight today, it’s still not understood why we do this. As human beings we go back and forth from non-REM to REM sleep every 90 minutes. REM sleep is the time when we dream, and in non-REM sleep we don’t. During REM sleep we go into paralysis. We may dream we’re moving, or running, or fighting, or flying, but we don’t move our bodies accordingly unless we have a condition, common in older men, called REM sleep paralysis failure, which is when our brains don’t switch off our bodies. And in some cases this can even result in people lashing out at their spouses. Then on the flip side there is a REM sleep paralysis excess, which is very common. Most people experience it once or twice in their lifetimes, and some a lot more. It’s when you’re coming out of REM sleep and gaining consciousness, but your brain has forgotten to tell your body to turn off its paralysis, and you experience being pinned. If your brain has no way of understanding or processing what’s happening to it, it can get confused and jump to some extreme conclusion to explain the experience, such as alien abduction. A sense of paralysis, a sense of there being an intruder, a sense of fear… Or if not aliens, a poltergeist, a fairy, or some other culturally appropriate boogie man.

Dreaming, as I said, happens during the Rapid Eye Movement phase of your sleep. Whether you remember it or not, everyone dreams, every night. Dreams have had a major impact upon human civilization. In the Bible alone there are countless examples of people having dreams, and those dreams being interpreted as messages or warnings. In Matthew 2, the Magi are warned not to return to King Herod through a dream. In the story of Joseph and his coat of many colours, dreams play a big part. The whole story hinges upon the future Joseph sees in his dreams, and his ability to interpret dreams for the Pharaoh. It’s not surprising that these sorts of stories find their way into the Bible, because we as human beings tend to imbue our dreams with subjective significance. Because our dreams are weird, and it’s not intuitively obvious what our dreams are for. We all dream. The purpose of dreaming is not to relay secret messages to us, or tell us the future, obviously. But rather it’s a kind of emotional therapy that we all need.

"Asleep" ,1902 Samuel Melton Fisher

"Asleep" ,1902 Samuel Melton Fisher

In REM sleep we relive experiences, or aspects of experiences, but we relive them in an emotionally repressed state. And in this way, we’re able to process serious to minor trauma more effectively, because we can relive them without responding to them emotionally, and therefore, process them more effectively. This is an important part of the healing process. Soldiers who are suffering from PTSD, on the other hand, are suffering in this way because unlike most of us who during our REM dreaming state are separating our emotional response from our memories, people with PTSD don’t do this. Therefore, as they relive their traumatic memories of war (for example), they respond to them emotionally as if they really are reliving them again. They respond to them in the same emotionally charged way they did the first time. And so, people with PTSD have to be taught to process such trauma in a wakeful state, because their brain is failing to process such trauma while they’re asleep. Dreaming is critical for our emotional well-being. We all know that a lack of sleep leads to emotional instability. We’ll say it casually – ‘someone is grumpy today, they probably didn’t sleep well last night’. And indeed, psychiatric health in general has a strong causal link to sleep. Almost every psychological abnormality goes hand-in-hand to some extent with disrupted sleep.

The other significant role of dreaming is its effect on our creative output. Many people in history have reported that their best ideas have come to them in dreams. A famous example of this is Mary Shelley, who dreamed of her monster before writing her novel – Frankenstein. But there are many example like this. Another one is George Lucas, who dreamed of a lightsaber battle before going on to create the Star Wars saga. When we dream, we process all our memories and find associations we couldn’t see when awake, because our dreams will associate ideas together which we wouldn’t consider associating in a wakeful state. And that is the basis of creativity, finding connections between ideas which are not obviously related. Hence the old saying, ‘you should sleep on a problem’. It really does help in our ability to see new solutions. So, REM sleep is critical, and our brains will actually induce more REM sleep on a given night if during that day we have had more sensory input, or we experienced some degree of trauma.

Peter Tripp kept awake in 1959.

Peter Tripp kept awake in 1959.

So, back to the main point, a lack of sleep causes you harm. Tests have been done on rats, for example, where you give them all the food and water they need, but you prohibit them from sleep, and in such cases rats will die as quickly as if they were being starved. Similarly, in humans, there is a very rare condition in which people are unable to sleep entirely – and again, in such rare cases, humans will die quite quickly. The world record for staying awake is… There is no world record. The reason for that is the Guinness world record keepers view trying to stay awake for prolonged periods of time, long-term sleep deprivation, as so dangerous they refuse to recognise such records. Back in the 1950s when the world record was recognised, there was a famous New York DJ called Peter Tripp, who, for charity, tried to beat the then record of 8 days straight with no sleep. That’s 200 hours. Going into the test of endurance Peter Tripp was a healthy, married, 33-year-old man. After 3 days, he entered a psychotic state. He became aggressive with everyone around him, believing they were trying to poison him. His body temperature dropped, and he began to hallucinate. By the fifth day, he had no sense of who he was. He’d had a complete break with reality. It’s amazing to me that they didn’t call an end to the experiment, but they proceeded regardless, keeping Peter Tripp awake for the 200 hours as planned. As the end was in sight, those around him were just playing the constant game of telling him who he was and why he was doing what he was doing, as he didn’t know. Finally, when he’d beaten the record and he was able to sleep, he slept 24 hours straight. But permanent damage had been done. At first it seemed like he was fine. But in the subsequent days and weeks, his wife reported that the man she knew was gone. Their marriage crumbled apart; he had serious emotional problems. Peter Tripp was a cognitively diminished man, who subsequently lived out the rest of his days as a door to door salesman.

A lack of sleep is really a significant culprit in all the various things which can go wrong with us. Our immune system only works properly if we’re getting sufficient sleep. Even one bad night’s sleep destroys our body’s ability to adequately fight off disease. Insufficient sleep dramatically increases your risk of getting certain types of cancer. So strong is the correlation that the World Health Association classifies shift work as a probable factor in causing cancer, because of the sleep disruption shift work can cause. We’ve all heard of examples of famous people who claim to need little sleep. Margaret Thatcher, Ronald Reagan, and the current president Donald Trump have all claimed to need little sleep. Thatcher, who kept her speech writers awake with her until 2 or 3 in the morning, would then be up in time to listen to Farming Today at 5am. Margaret Thatcher and Ronald Reagan both then developed dementia in later life. According to Matthew Walker this is no coincidence. And as for the current president, last week fresh claims were made attesting to his declining mental health; again it may not be a stretch to look to his lack of sleep as a culprit. The correlation between disrupted sleep and dementia is very strong. Some research even suggests it may be the primary cause of dementia.

And that covers most of it. A lack of sleep damages your body and brain’s health, pretty much across the board. Sleep less than 7 hours and you are causing yourself harm. Finally, dreaming is essential in learning, both before and after. When we sleep our brains essentially turn into dry sponges ready to suck up new knowledge; without sleep our brains cannot lay down new memories. It’s often said that our ability to learn new skills or remember things generally deteriorates with age, and the reason for that is the quality of sleep we’re able to get tends to deteriorate with age. One of the best arguments to support why sleep is so important is to think about sleep from an evolutionary perspective. When we sleep, we’re not gathering food, or finding a mate, and we’re in a defenceless state. In terms of humanity’s ongoing survival, sleep seems to fly in the face of everything that’s important. And yet still we sleep. Sleep outweighs all these catastrophic detriments. The importance of sleep cannot be underplayed. And with that, I’ll say sleep well and Amen.