Why We Sleep

June 27, 2019

I have to start off by saying that I find it quite ironic that I have chosen to write this post today after the worst night of sleep. I am currently in the middle of exam period and am pretty much self-sabotaging parts of my health to get everything I need to done. One of the most important elements of getting a good night of sleep is routine…something I don’t quite have a hold of at the moment. In addition to this I have been spending hours on end behind my computer screen and consuming moderate (in my opinion) doses of caffeine. Enough about me for the moment, let’s get into why we sleep.


A resounding number of people requested for me to write a little bit about sleep on Tuesday and I was very fortunate that it was a topic of conversation in my favourite podcast last week. I like to think of Ella Mills and her husband Matthew Mills as leaders in the area of overall health and wellbeing. They truly live and breathe everything they say. I am inspired by their dedication, motivation, passion and drive. The ‘Deliciously Ella Podcast’ (which the two of them host) features authoritative figures in the area of health. Last week they interviewed Professor of Neuroscience at the University of California, Berkley, Matthew Walker. Walker has published a book titled ‘Why We Sleep’ and he along with Ella and Matthew try and get to the bottom of that in their detailed discussion. Now I am not going to come in and reiterate everything that was said (although I will leave the details below if you do want to check it out), however I do want to share elements of it I found really useful and I think you might be interested in too.


Now to make everyone feel a little better, two thirds of adults in developed nations fail to get the recommended amount of sleep. We can all take a sigh of relief in knowing that we are not alone. On the other side of this, however, is that if sleep is so important why are so many of us neglecting it?


Adults should be sleeping between seven and nine hours every night (eight is about the sweet spot). Depending on your lifestyle, age and other factors the amount of sleep required will vary. In the 1940s the average person was getting 7.9 hours of sleep a night. Today in the UK the average number of hours of sleep a night is about 6 hours and 49 minutes – that is down about 15 – 20 per cent!! I sleep about 8 hours every night…with the last couple of weeks as an exception. How is it though that we have become so comfortable and accepting of getting less sleep?


Speaking for myself I know that I just don’t make it a priority. Walker describes this as “sleep procrastination.” I will get into bed and then think of a couple more ‘productive’ things I could be doing like paying my phone bill, writing my to do list for the next day or writing down a new recipe that has just come to my head (me last night). Unfortunately, this means that I am so wired by the time that I go to sleep that I spend the next 30 minutes to an hour trying to turn off so I can actually rest. I get frustrated thinking “I have the opportunity to sleep now and my head just won’t turn off,” when I know all too well that it is self-inflicted.


Let’s take a step back and see what is actually going on when we close our eyes and go to sleep. Human beings have two types of sleep. One of them is called rapid eye movement sleep (REM sleep – when we dream) and the other is non rapid eye movement sleep (Non-REM sleep). Non-REM sleep is divided into four stages called Stage 1, Stage 2, Stage 3 and Stage 4. When you start to fall asleep you enter into light Non-REM sleep (Stages 1 and 2 of Non-REM sleep). As you get deeper into sleep, say for the next 60 to 70 minutes, you will move into Stages 3 and 4. Stages 3 and 4 are the deep restorative stages of sleep. You will then have a short REM sleep and then go back into Non-REM and to REM again. This is known as the ‘Sleep Cycle.’ This cycle lasts 90 minutes in humans and will repeat over and over again throughout the night. It is important to note here that every stage of sleep provides some kind of beneficial function


Sleep is essentially your life support system – Matthew Walker.


Well that is a bold and somewhat terrifying thought isn’t it! As it turns out, there is a causal link between lack of sleep and some of the most feared diseases in the developed world – Alzheimer’s Disease and Cancer. At night time when we go into deep sleep our brain behaves as a sewage system to cleanse toxins from our body. One of the proteins that is linked to Alzheimer’s Disease that is being cleaned up is beta-amyloid. If we don’t get enough sleep, we are taking away the opportunity our brain has to clean up this protein and risk its build-up in the body. Looking now at Cancer, which also has a causal link with sleep. In our immune system there are these cells called ‘Natural Killer Cells’ that really act as the secret service agents of the immune system. Their role is to seek out and identify any dangerous unwanted elements present in our body, including cancer cells. Every person has cells in their body that are cancerous and it is the Natural Killer Cells that are responsible for ensuring that those cells do not become the disease we know as Cancer. Studies have found that if you take a group of people and restrict them to four hours of sleep for just one night, there is a 70 per cent drop in Natural Killer Cell activity. This state of immune deficiency is present after just one night of bad sleep, how shocking is that!


Now there are a number of things we do in our day to day lives that affect our sleep pattern so I am going to go through a few of them.


Caffeine: We begin with caffeine (because I love coffee and chocolate). I found this one particularly interesting when it was being discussed in the Podcast. Caffeine has a long duration of action. It has a half-life of 6 hours and a quarter life of 12 hours. This means that if you choose to have a coffee with your lunch at about 12 o’clock noon then a quarter of that coffee is still swirling around your brain at midnight! That is like taking a quarter shot of coffee right before you turn the lights off before sleep. Professor Walker recommends having your last coffee or caffeinated beverage 12 to 14 hours before you go to sleep. That means that if you are waking up at 7 o’clock in the morning you should really have your last coffee at 10 o’ clock that morning. If you have a coffee any time after dinner you are actually decreasing the amount of deep sleep you have by 20 per cent! For you chocoholics out there you will be pleased to know that chocolate does have less caffeine and won’t make you as wired as coffee. Professor Walker recommends just taking note of any sleep changes if you are having chocolate in the afternoon and determine whether or not it works for you.


Stress: Having your mind in a state of “fight or flight” before bed it makes it nearly impossible to fall asleep. In fact, the leading cause of insomnia is stress and anxiety. Professor Walker recommends taking a pen and paper an hour before bed and physically writing down your worries. This will help to calm down your nervous system. A study has actually found that by doing this you can actually decrease the time it takes for you to fall asleep by 50 per cent.


Food: We don’t want to be going to bed really full or hungry, just somewhere in between. It is recommended that we try to stop eating three hours before bedtime. This will give the digestive system time to do what it has to do so you don’t feel too restless.


Exercise: The quality of our deep sleep is actually greatly improved with regular physical activity. A good night of sleep also has a high correlation with having the motivation to exercise more intensely the following day. A good night of sleep also decreases the risk of injury.


Technology: The one I am sure so many people are interested in. Professor Walker discussed a study where people did one hour of iPad reading before bed. It found that by doing this, 50 per cent of the body’s melatonin (the hormone that regulates sleep-wake cycles) was blocked and unable to properly peak again for another three hours. He recommends staying away from blue light (on phones and iPad) at least an hour before bed. If you do need to use these devices, then blue light blocking glasses or putting your phone on black and white can help.


Now I know I have bombarded you with a lot of information so I am going to use Professor Walker’s top five points for good sleep to tie it all together:


  1. Have a regular sleep and wake cycle: This means trying to go to bed and wake up at the same time every day. Even if you have had a shocking night of sleep still get up the following morning at the same time. Push through the tough day and then go to bed that night at your regular time to keep the cycle in sync.

  2. Surround yourself with darkness before bed: Put away the screens an hour before bed and try dimming and switching off at least half the lights in your house. This will tell your body that it is nearly time for bed.  

  3. Keep yourself cool: In order to fall asleep and stay asleep our core body temperature actually needs to drop one degree Celsius. The ideal bedroom temperature for most people will be between 18 and 18.5 degrees Celsius.

  4. Walk around if you can’t sleep: This is something I should have done last night. If you find yourself awake and unable to fall asleep within 15 to 20 minutes get up and go to a different room. Sit in some dim lighting (this is not the time to whip out your phone) and wait until you feel sleepy again. Then you can return to bed for a good night’s sleep.

  5. Be mindful of alcohol and caffeine consumption: I didn’t get into alcohol in this article but there is heaps of information in the podcast if you are interested (details below). Remember, try and cease caffeine consumption 12 to 14 hours before bed. If you do feel a slump coming on at 3 o’clock in the afternoon get physically active, get daylight and fresh air or have a hot drink (like a herbal tea).


I have been using an app called ‘Sleep Cycle’ to track my sleep for the last couple of weeks. I find it so interesting seeing my sleep cycles visually. The apps are about 60 to 70 per cent accurate so they can’t be interpreted literally. They are, however, a great tool to keep us mindful of making sleep a priority. I have shared my best and worst night of sleep for you to check out!


Good night of sleep 



Not a great night of sleep 


For more information on this topic you can check out the ‘Deliciously Ella’ Podcast episode titled ‘Why We Sleep’ available on Spotify and all other major podcast platforms. In addition, you can get your hands on Matthew Walker’s book ‘Why We Sleep’ for even more in depth information. I hope that this post was helpful and inspires you to make sleep a bit more of a priority.





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