Sleep: Your Natural SUPERPOWER
Sleep is an overlooked but important aspect of our lives
This post details the importance of sleep and how it impacts us. Sleep is all too often the first thing many people seem to sacrifice when they have a goal in mind. Whether to watch their favourite TV show or to progress their career. But over the past 20 years, science has gained a much deeper understanding of sleep. It shows just how detrimental it is to sacrifice sleep as much as we do as a society.
This article aims to give you an understanding of sleep and the mechanisms that power it. Then we discuss what the research shows about getting poor sleep by either staying up too late or shortening sleep duration. Finally, we review systems and tools you can implement to get adequate and restorative sleep.
Today we turn our attention to sleep. Science did not have a good understanding of sleep until recently. Visionaries like Matt Walker and others have done groundbreaking research on sleep and made it mainstream. And yet, about 62% of adults worldwide still feel that they don’t sleep well, with only 10% saying that they get adequate sleep and feel rested. Self-reported sleep surveys show that developed countries take up the bottom five spots out of 12 countries surveyed despite experts emphasising that sleep contributes to our physical, mental and emotional well-being. Developing good sleep hygiene is an important first step to overall well-being.
What is sleep?
Scientists are still determining the exact reason why we sleep. But to answer this question, countless studies have looked at what happens to the brain when we don’t sleep. The findings show that sleep impacts almost every tissue and system in the body. Mattew Walker, from UC Berkley, who has pioneered research in sleep, defines sleep as follows:
… the single most effective thing we can do to reset our brain and body health each day — Mother Nature’s best effort yet at contra-death.
-Matthew Walker, Why We Sleep
Mechanism behind sleep
Since you woke up earlier today, two processes have been happening in the background determining when and how deep you sleep. They are:
- Circadian rhythm; and
- Sleep pressure.
Circadian rhythm
Circadian comes from the Latin words circa, meaning approximately, and dies, meaning day. You can think of it as an internal 24-hour clock determining your sleepiness and wakefulness throughout the day. Like a graph with time on the x-axis and your body’s ability to function on the y-axis.
The circadian rhythm is set by external stimuli such as light and temperature. It can also be affected by our chronotype, colloquially known as night owls or early larks.
Sleep pressure
While our body is awake, a neurotransmitter called adenosine is continually produced by our body. A good analogy for explaining this would be water stored upstream of a dam. The more adenosine in our brains, the more sleepy we feel. This adenosine is washed out of our system when we go to sleep. From our earlier analogy, the floodgates are opened, and water rushes out of a dam. It can be visualised as shown in the graph.
Dangers of sleep deprivation
The current consensus among many sleep experts says that we need between seven to nine hours of sleep every night. Sleep deprivation or not getting enough sleep has been linked to many illnesses, some of which are highlighted below:
- Weak immune system;
- Heart problems;
- Obesity;
- Memory consolidation;
- Mood;
- Poor mental health; and
- Reduced safety (e.g. while driving).
This is by no means a comprehensive list. System, a platform linking different concepts based on research data, has linked sleep to 137 other topics. I have showcased some which I found to be particularly interesting below.
Research on sleep deprivation
Perceptual changes
This systematic review study [1] looked at research done in the past that took healthy individuals and deprived them of sleep 24 hours to 11 nights. The study looked at 21 research papers examining the connection between sleep deprivation and psychopathological symptoms. They found a progression of perceptual changes that occurred as early as 24 hours, with symptoms of delusion occurring between 72 and 190 hours. A breakdown of time awake and symptoms experienced can be seen in the image below.
Source: www.ncbi.nlm.nih.gov
There is some good news from the study. Most of the conditions experienced were resolved after a period of sleep. Yet this study provides a small window into what could happen if we were sleep deprived for a long time.
Impairments to cognitive and motor performance
This study [2] compared the effects on performance between a group who were sleep deprived and another that was drunk. Tests were conducted to measure their cognitive and motor performance, such as hand-eye coordination, reaction time and memory. The study found that for individuals that had gone 17–19 hours without sleep, performance on some tests was equivalent to or worse than that of blood alcohol content of 0.05%, which is over the legal limit in many countries.
This study shows that being sleep deprived could impact performance just as much as being drunk with alcohol. This has also been backed up by several studies [3] examining sleep deprivation and alcohol ingestion.
Occurrence of depressive symptoms
This cross-sectional study [4] investigated the relationship between sleep duration and depressive symptoms in adolescent girls. A questionnaire was used to determine depressive symptoms by assigning them a score between 0 and 27. Similarly, sleep duration was assessed with a question on the questionnaire.
The study found that less than seven hours of sleep had the highest percentage of depressive symptoms (45.7%), with those getting 8 hours only having 16.7% with depressive symptoms. Another study [5] also supported this, which looked at pharmacy residents for whom the odds of depressive symptoms were linked to inadequate sleep.
Comparing the percentage of depressive symptoms against the duration of sleep. Source: www.ncbi.nlm.nih.gov
This may be a lot to take in. Still, time and time again, we see the data converging on a single point: improving sleep improves your well-being.
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How to get good sleep
If you have made it this far into this post, raise your palm, place it on your shoulder and give yourself a pat on your back. Now for the fun stuff, tools and systems to improve your sleep.
Tools for better sleep
The following stimuli greatly impact your ability to produce and sustain good sleep. They are:
- Light and darkness;
- Body and ambient temperature;
- Food; and
- Exercise.
Each of these stimuli or tools can be utilised to improve our sleep.
Light and darkness
Light has a big impact on our circadian rhythm. It impacts the cortisol levels early in the morning, which impacts our wakefulness during the day and the secretion of melatonin, which signals our brain that it is time to sleep during the night.
Andrew Huberman, a Stanford professor and podcaster, tells us there is a diabolical twist in the artificial lights both from indoor fixtures and from our phones. The light emitted by them is not strong enough to provide for our requirement of sunlight in the morning, but they are strong enough to disrupt or delay sleep onset during nighttime.
Recommendations
- Get good sunlight at a low solar angle during the day.
No need to stare right into the sun. Just looking in the general direction is adequate.
No need for sunglasses during this morning’s sunlight viewing. Prescription glasses are acceptable. - Avoid bright lights from overhead lights and phone screens during nighttime.
Dim your indoor lights to a point where you can do your tasks safely, use light closer to the floor, like reading lamps and avoid bright overhead lights.
Avoid using screens closer to bedtime. If necessary, reduce its brightness and use a warmer display colour temperature.
Body and ambient temperature
Our body temperature has a linear relationship [6] with our wakefulness. An increase in temperature increases our wakefulness and vice-versa. Our bodies drop in temperature before we go to sleep and increase in temperature just before we wake up.
Therefore, we would have to aim to increase our body temperature in the morning and decrease our body temperature at night.
Recommendations
- Take a cold shower after waking.
Although it may seem paradoxical, a short 1–3 minute cold shower increases our core body temperature. It makes us feel more awake. - Take a warm shower before bed.
As above, a warm shower decreases our core body temperature, making us feel more relaxed.
Food
Food ingestion, in general, has the effect of increasing our body temperature, which in turn increases our wakefulness. The main parameters when it comes to food ingestion are:
- What you eat
- How much you eat
- What time you eat.
Coffee
The active component in coffee, caffeine, helps improve our wakefulness by blocking the receptors in the brain to take in the sleep pressure signal. Therefore it makes us feel more energetic. During this time, the production of adenosine isn’t halted, meaning when caffeine leaves our system, all the built-up adenosine hits all at once, making us exhausted.
Caffeine also has a half-life of around 12 hours, meaning half of the caffeine ingested at any given time takes 12 hours to leave our system.
Alcohol
Alcohol is part of a class of drugs known as sedatives, which make us feel sleepy. But studies have shown that the sleep that we get after drinking alcohol is disrupted sleep. It impacts how deeply we sleep and how much REM sleep we get throughout the night.
Recommendations
- Eat a light meal around two hours before bed.
A late dinner has been shown to disrupt sleep. Therefore giving your body time and a manageable amount of food before bed can help.
Aim to have your last cup of coffee by 2 pm.
This ensures that half of the caffeine is cleared out before bedtime. - Avoid drinking too much alcohol too close to bedtime.
This helps reduce the impacts to sleep caused by alcohol.
Exercise
Exercising also increases body temperature, thereby increasing wakefulness. Exercise is a great way to feel more alert during the day. Here are some recommendations to help integrate exercise into your daily routine.
Recommendations
- Go for a walk after waking.
This helps make you feel awake. Also, you can get the positive effects of light exposure early in the morning. - Aim to hit the gym three to six times a week at a consistent time.
Going to the gym consistently has many benefits, with sleep being one of them.
When sleep is abundant, minds flourish. When it is deficient, they don’t.
― Matthew Walker, Why We Sleep
Hope you found some use in today’s post and used it as a starting point to delve deeper into this topic. What was your key takeaway from this post? Do you plan to implement any of the recommendations? Or do you have some more tips and tricks for us? leave them in the comments below or tweet at me. Thank you very much for reading, and I’ll catch you in the next one.
Until next time,
Tony
Additional Resources
- Article: WEF; NINDS
- Masterclass: How to Sleep Better
- Infographic: Raconteur
- Research: 1; 2; 3; 4; 5; 6
- Sleep Foundation: Recommended Hours; Physical Health; Light; Alcohol; Dinner
- System: Sleep
- Questionnaire: PHQ-9
- YouTube: Huberman Lab
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