When was the last time you woke up to go to work or university feeling perfectly refreshed, awake and ready to start the day, without the need for caffeine or a nap? Can’t remember? You’re not the only one. In 2014 the World Health Organisation declared sleeplessness as a public health epidemic. The set-up of modern society, with its often 10 hour working days, long commutes and the necessity to have some sort of a life outside of your day job, means that millions of individuals are systematically getting way less than 8 hours of sleep every night.
Sleep Deprivation and You
Many people love to profess that they don’t need any more sleep, that they function perfectly well with a mere six hours. However studies have shown that lack of sleep actually inhibits the part of your brain which is responsible for self-assessment, meaning that when you aren’t getting enough shut eye, you have no idea how it’s affecting you. This effect is cumulative, to the extent where people who have been chronically sleep deprived over a number of years actually acclimatise to their impaired performance, lower levels of alertness and reduced energy levels. They genuinely have no idea that they live their lives with sub-optimal mental capacity and physical vitality, never really accessing their true potential, and all due to them persistently choosing to not sleep enough.
Sadly, snoozing for 12 hours at the weekend won’t save you either. In Matthew Walker’s book ‘Why We Sleep’ he shows that you only get one chance at reaping all of the benefits sleep has to offer. Get too little sleep, and while your brain attempts to make up for it in the following nights, doing so completely is impossible and the damage is already done. The only means of preventing sleep deprivation is to get your full eight hours each and every night. Walker shows that even if you get seven hours sleep – an amount many would normally think is quite good going – on the tenth day, the brain is as dysfunctional as it would be after going without sleep completely for 24 hours. Three full nights of recovery sleep (more nights than in a weekend) are insufficient to restore performance back to normal levels after a week of short sleeping.
So what exactly does this mean? Well, sleep affects just about every process in your body. When you are sleep deprived, your prefrontal cortex essentially shuts down. This is the part of your brain which is responsible for planning, personality expression, decision making, attention control, reasoning and problem solving – not something you want to be doing without. In contrast, a greater amount of activity is shown in your amygdala. This is the part of your brain associated with processing emotional information: the less sleep you get, the more likely you are to interpret situations negatively, to have greater emotional fluctuations (bigger highs and lows) and to just be overall a lot moodier.
While heightened emotions due to lack of sleep might not be a great surprise to anyone, sleep is also key in hormone regulation. In a study on the effect of sleep on weight loss, those who had 5.5 hours sleep lost 55% less body fat than the group on the same diet who received 8.5 hours sleep. While the sleep restricted group did lose some weight, they lost 60% more muscle and other fat-free mass. They also had much higher ghrelin levels – the hormone which causes you to retain fat and feel hungry. Cortisol levels were much higher, leading to increased stress levels, an increase in visceral fat and your body being more likely to break down muscle. Both the satiation hormone leptin and human growth hormone (the youth hormone) were also present in much lower levels.
Sleep is also responsible for clearing out any metabolic waste which has built up in the brain during the day. Insufficient waste removal is heavily linked to many neurodegenerative diseases such as Alzheimer’s. More broadly, sleeping only six hours on a regular basis means that you are 12% more likely to die prematurely than somebody who sleeps for 8 hours. Essentially, the effects of sleep deprivation can be so insidious, that the phrase ‘you can sleep when you’re dead’ is way more likely to be a self-fulfilling prophecy.
Depriving yourself of sleep not only has consequences for your own physical and mental wellbeing, it may also have fatal consequences for those around you. Drowsy driving causes 1.2 million car accidents in the US every year – that’s one every 30 seconds. In fact, driving whilst sleep deprived causes more accidents than driving on alcohol and drugs combined. When you are sleep deprived, you experience what is known as microsleeps, where your brain falls asleep for a split second without you even realising. Experience a microsleep at the wrong time, and you fail to even attempt to brake when a child runs across the road in front of you.
If you are operating on minimal sleep and you combine it with alcohol – even just to the extent that you are still legally able to drive – the effects on your likelihood of a crash are multiplicative. A study showed that individuals who were either sober but only got 4 hours sleep or who were well rested but legally drunk were six times more likely than the well-rested, sober control group to have off-road deviations. The group with 4 hours of sleep and a legal amount of alcohol in their blood stream were 30 times more likely to drive off the road.
Walker also points to the excessively long shifts forced upon doctors and other medical staff. Often forced to work 24 hour long or even 30 hour long shifts, in doing so both the medics and patients are placed at much greater risk. Residents working 30 hour shifts will commit 30 percent more serious medical errors compared to those working 16 hour shifts or less. After a 30 hour shift with no sleep, they will make 460 percent more serious mistakes working in an intensive care unit than if they were well rested. They are also way more likely to hurt themselves – 73% more likely to stab themselves with a hypodermic needle or to cut themselves with a scalpel, not to mention the dangers of driving home after such an exhausting shift.
Ironically enough, the doctor who founded this extreme practice, William Halsted M.D in the 1800s, who viewed sleep as a dispensable luxury which detracted from the ability to learn and work, was an extremely heavy cocaine and morphine addict. It seems absolutely ridiculous that even with this knowledge, the standards formed by his cocaine infused wakefulness are still imposed on medical students to this day.
Sleep is a combination of two waves: NREM and REM. NREM is what is known as ‘deep sleep’. Here your brain consolidates what is has learnt for the day, pressing ‘save’ on all new memories as it physically moves information from the short term memory to the long term. It therefore not only saves existing memories, but clears the short term memory capacity to make new memories and acquire new knowledge. The brain replays the events of the day up to 10 times faster, backwards, forwards, and skipping around. It is essentially reviewing all of the information it has learnt and placing it into context with your life experience.
So effective is this process, that memory retention following an 8 hour nights sleep relative to 8 hours of awake time increases memory retention by up to 40 percent – the difference between pass and fail in an exam. Even naps as short as 20 minutes can offer a memory consolidation advantage, given that they contain enough NREM sleep. Next time you consider pulling an all nighter before an exam, just remember that not only are you foregoing the memory benefits from sleep, but you’ll effectively be doing it drunk. Go without sleep for 20 plus hours, and the effect on your brain is the same as if you have drunk two glasses of wine.
NREM sleep is not only crucial for memories relating to facts and information, but for motor skill memories as well. Studies show that getting 8 hours of sleep resulted in a 35% increase in accuracy and 20% increase in speed when individuals were asked to memorise and perform an 8 digit keyboard combination. This clearly has significant implications for athletes, musicians or just for the day to day motor functioning abilities of any individual. NREM sleep is also critical for injury reduction, with 9 hours of sleep reducing injury likelihood for NBA players to 15%, down from a 75% likelihood at 6 hours of sleep.
A Dream Come True
REM sleep is the stage of sleep where you dream. Unlike the NREM, this happens in real time and is when your brain makes sense of everything that has happened, and prepares you for anything important that could happen, such as how you would react if Beyoncé enrolled in your maths lectures or if Adele told you to take her place at Glastonbury.
REM sleep supercharges your creativity levels. Throughout history, countless people have claimed they came up with ideas in a dream: Paul McCartney’s ‘Yesterday’, the Periodic Table, Google, even Frankenstein. In an experiment, groups were given a number puzzle with a certain trick to it which would speed up the solving of it. The group who came back after a full night’s sleep were 2.5 times more likely to have worked out the trick relative to groups who stayed awake for the same length of time (either overnight or during the day).
REM is also when your brain emotionally cleanses the memories of the events that happened in the day. If you think back to something which affected you emotionally when you were a child, while you have a memory of being upset, it doesn’t prompt you to relive the same degree of emotional charge all over again. This is because your brain has wiped away the emotional reaction through REM sleep: it at once preserves the knowledge so that we learn from whatever salient experience we might have had and simultaneously disentangles it from the painful emotional accompaniment. If this did not happen, then we would probably live in a constant state of chronic anxiety – every time we recalled some form of autobiographical memory we would be thrust into a state of emotional turmoil.
In a series of studies, Dr Rosalind Cartwright examined individuals showing signs of depression due to a difficult emotional experience, such as devastating break ups or painful divorces. Measuring their sleep patterns around the time of the incident and catching up with them a year later, she showed that only those who had explicitly dreamed about the incident at the time were one year later clinically healed, demonstrating emotional closure and showing no tendency for a depressive recurrence when reminded of the incident.
This also has very strong implications for PTSD sufferers. Those with post-traumatic stress disorder suffer from abnormally high levels of the stress hormone norepinephrine when they sleep – inhibiting the ability for REM sleep to cleanse their memories of the emotional charge and resulting in veterans reliving the entire emotional distress of a traumatic experience on, say, hearing a car backfire. The recurring nightmares that form a critical part in diagnosing PTSD, are actually your brain’s way of continually trying night on night to strip away the emotional association with the traumatic memory. When administered a drug with a side effect of lowering norepinephrine levels, REM sleep was allowed to operate as it should, the nightmares ceased and overall severity of their PTSD improved immensely.
Circadian Rhythm and Blues
Both NREM and REM are crucial for adequate brain function, the development of emotional intelligence, creating memories and functioning as a human being. However the two are not distributed evenly throughout the night. As the graph below shows, the beginning of the night is much more NREM dominant, whereas the early hours of the morning are more heavily saturated with REM sleep. The biological asymmetry here means that not getting your full eight hours of sleep therefore robs you significantly: either of the nurturing NREM rich sleep, or of the creativity stimulating REM rich sleep.
The timing at which you can optimally achieve these 8 hours of sleep is determined by your circadian rhythm. This is the term for your body’s innate sleep clock – when it naturally wants to go to bed and wake up for maximum efficiency and therefore produces the internal conditions to do so. This varies across people. Around 30% of the population are early risers, they prefer to go to sleep between 9 and 10, and feel refreshed and energised waking up at 6am. Another 30% of the population are night owls, optimally sleeping from between 1am-3am, waking sometime around 11am. The remaining 40% of the population are somewhere in the middle.
The idea behind this from Mother Nature was to facilitate shift watch at night time. Splitting the population in this way means that there would only be four hours of night time vulnerability rather than eight. Sadly, in the modern day this results in the 9-5 lifestyle actively robbing nearly 70% of the population of those precious REM hours of their sleep cycle. While a night owl may attempt to sleep from 10pm to 6am, their body will not produce the conditions necessary for that crucially nourishing, rejuvenating sleep until 1am, giving them only 5 hours of useful sleep a night. They will wake up groggy and disorientated, not feeling properly awake and productive until at least midday, if not the afternoon.
Circadian rhythms also vary between age groups. As a baby you naturally sleep and rise very early. As teenagers, your circadian rhythm jumps to be way later than the average adult, meaning you naturally desire to go to bed around midnight, waking up in the late morning and receiving your nourishing sleep as you do so. This is evolution’s way of slowly giving teenagers a taste of independence – a few precious hours after everyone else has gone to bed to see what the world is really like. As you get older and reach your mid-twenties, your circadian rhythm gradually creeps back, becoming earlier and earlier until it is much more likely to match that of your parents.
Early school times, therefore, have a hugely detrimental effect on both the physical and mental wellbeing of teenagers. Depriving teenagers – an age group most susceptible to developing chronic mental illnesses – of their precious hours of REM sleep could make all the difference between psychological wellness and lifelong psychiatric illness. A study in the 1960s deprived a group of young, healthy adults completely of REM sleep for a week. By the end of the third day subjects were hallucinating, they became paranoid, anxious and moody.
Starting school so early also restricts the intellectual development of teenagers. A study tracking more than 5000 Japanese schoolchildren showed a direct relationship between those who slept the most and those who went on to develop superior IQ levels. In Minnesota, shifting school start times from 7:30am to 8:30am drastically increased the average verbal SAT scores within the year from 605 to 761.
Most shockingly of all, delaying school start times actually increases the life expectancy of students. The biggest killer of teenagers in America is road accidents. When a school in Wyoming pushed back its start times from 7:35am to 8:55am, this resulted in a 70 percent reduction in traffic accidents in 16-18 year old drivers. To put this into context, the introduction of anti-lock brake systems decreased road accidents by 20-25 percent, and was deemed a revolution.
Honestly, this stuff needs to be taught in schools. In my own experience I’ve had the importance of a good diet and regular exercise impressed upon me many times, including weekly mandatory PE. I’ve had classes dealing with alcohol, drugs, sex and reproductive health. Yet I don’t think I have once had any sort of lesson telling me why a good night’s sleep is so important.
In the workplace, a big change in culture is required. Naps should become common practice, as should flexible working schedules to accommodate different sleep patterns. Firms such as Google and NASA already do similar things, as they clearly recognise the productivity benefits this brings them. The insurance firm Aetna goes even further, offering financial bonuses to employees based on the amount of sleep they can prove they have gotten using sleep tracking devices.
There is a great need for better public health campaigns, particularly with respect to drowsy driving awareness. The same sleep tracking devices used by Aetna could be used to inform car insurance costs, leading to both safer roads and an increase in overall health levels.
Most important of all is the need to address the relationship between sleep deprivation and those on a low income. Working class individuals are more likely to work in the service industry, requiring antisocial hours or even working night shifts. This robs them of the sleep they need to access their mental and physical potential, increasing the likelihood of developing chronic illnesses at a much earlier age and limiting their overall productivity levels. This will restrict their earning potential and the jobs available to them, in turn preventing them from breaking free of this sleep deprivation poverty trap. Further, kids of working class families are less likely to be driven to school, meaning they wake up earlier than their peers to catch buses or trains, being robbed even further of the intellectual development that sleep brings and increasing the likelihood that they will become trapped in the same way as their parents.
Personal Sleep Hygiene
So, in the absence of a complete societal overhaul, what can you do to increase your own sleep hygiene? Matthew Walker suggests the following 12 tips:
- Stick to a sleep schedule. Ensure you are going to sleep and waking up at the same time every day. Set an alarm for bedtime if that helps. As creatures of habit, our sleep efficiency responds best to this tip of them all.
- Don’t exercise too late in the day – no later than three hours before bedtime.
- Avoid caffeine and nicotine. Caffeine can take over 8 hours to wear off properly, meaning that a cup of tea in the afternoon can stop you sleeping at night. Nicotine is also a stimulant, meaning most smokers only sleep lightly.
- Avoid alcoholic drinks before bed. Alcohol robs you of your REM sleep and may contribute to impairment of breathing. You also tend to wake up once its effects have worn off.
- Avoid large meals and beverages late at night. Digestion can interfere with sleep, and large drinks will cause you to wake up to urinate more frequently.
- If possible, avoid medicines that disrupt or delay your sleep.
- Don’t take naps after 3pm. These can make it hard to fall asleep at night.
- Give yourself an hour to relax and unwind before bed. Reading, listening to music should be part of your bedtime ritual.
- Take a hot bath before bed. The drop in body temperature once you get out will make you feel sleepy.
- Dark, cool, gadget free bedrooms. The blue light emitted from most devices disrupts your natural sleep rhythm, so try to limit screen time for at least two hours before bed. Modern lighting and central heating also interferes with the signals your body uses to know that it’s bedtime. Also turn the clock’s face away so that you can’t see it as you attempt to fall asleep.
- Have the right exposure to sunlight. Get at least 30 minutes of natural sunlight every day, use very bright lights in the morning and turn them down in the evening time.
- Don’t lie in bed awake. If you find yourself unable to sleep for more than 20 minutes, get up and do something relaxing until you feel sleepy – the anxiety of not being able to sleep can make sleeping much harder.
There is clearly much to be desired within Western culture when it comes to our attitude towards sleep. ‘Work hard play hard’ attitudes often leave young adults with little to no time to rest and unwind and ‘time is money’ mantras really enforce the idea that doing so is a waste of your precious time. This is to the detriment of your quality of life, and hopefully this has shown that the best thing you can do for yourself is to ensure that you are getting a non-negotiable 8 hours of sleep, that you do your best to set up your life to ensure that this is the case for you and your family, and that you ignore people who claim they get by just fine on very little. If you don’t snooze you lose!
Want to read more? I would definitely recommend Matthew Walker’s book ‘Why We Sleep’, available here.