The Only Sleep Guide You’ll Ever Need

You can survive longer without food than without sleep. Let that sink in. As humans, we rarely miss an entire day without eating something. Why is it that we persistently miss out on sleep? If a lack of sleep is more dangerous than not eating, wouldn’t we make sure we received all we needed?

Human beings are the only species that deliberately deprive themselves of sleep for no apparent reason other than cultural and societal constructs. The 9 am-5 pm jam, or 8 am-3 pm school day. Shift work littering the medical society, factory workers, natural resources, and public service. Or the lucky investment bankers and lawyers who give up weekends and stumble through grunt years on chronic sleep deprivation.

No other species uses an alarm clock to wake prematurely. No other species artificially terminate sleep before they’ve had enough. It’s no surprise then that many of us wake up with our stress hormone (cortisol) levels through the roof, manifesting in an anxious mind. This is compounded by our immediate need to check our smartphones, which sets the tone for a tense morning more often than not. Our minds focus on the myriad tasks we need to get done, the people to reply to, and the work emails to respond to.

Humans did not evolve to deal with either of these seismic morning shocks to the system. Human sleep did not evolve to deal with any of the changes brought by the industrial era. The lights. The shift work. The smartphones. The alarm clocks. The cultural and societal expectations. The ‘hustle’ culture. The school start time.

The erosion of sleep has hit an all-time high. We are now sleeping less than we have ever done in what seems to be our species’ history.

In 1942, the average person slept 7.9 hours per night. Today, that number is 6.8 hours per night — a whole less hour. And the decline is accelerating.

Our physical and mental health’s resulting impact is dire: is it really a coincidence that mental health issues have moved in lockstep with the decline in our sleep? Matthew Walker, one of the worlds leading sleep experts, doesn’t think so.

This article is for you if you care about your physical or mental health and care about living to 100 years.

What is sleep, and what are the health benefits of sleep?

We all know what sleep is. Sleep is that altered state of consciousness we enter for one-third of our lives. What we understand less is why we do it. To date, scientists have not identified any one particular reason for requiring sleep. In fact, until the last twenty years, sleep was still one of the human species’ biggest mysteries. The reality is that we still don’t have all the answers, but we’ve come a long way thanks to people like Matthew Walker and Kirk Parsley.

As with any science, the studied outcomes of sleep deprivation are probabilistic, but it’s undeniable that the evidence is mounting. We’ll only scratch the surface of the evidence here because I’m guessing you’d prefer a summary of what the evidence is saying instead. After all, we don’t have all night.

Another reason we’ll only scratch the surface is that I want you to relate. And what can be more relatable than that frequent yawning, irritability, daytime fatigue, difficulty concentrating, lack of motivation to exercise, increased appetite, and propensity toward shitty foods? Sound familiar? Our bodies have a not so subtle way of telling us when they’re upset.

Addressing the question of why we sleep from an evolutionary perspective is interesting. When we sleep, we can’t gather food. We can’t socialise. We can’t reproduce. We can’t nurture or protect our offspring. Worst still, sleep leaves us vulnerable to predators in the surrounding environment.

Why would Mother Nature create a biological phenomenon like sleep if it leaves us so damn exposed? It appears to be one of Mother Natures’ most foolish creations. On any of these grounds, an intense evolutionary pressure to prevent the emergence of sleep existed, let alone all of them in combination.

Yet sleep has persisted. Valiantly so. In fact, every species studied to date sleeps. The perseverance of sleep throughout evolution indicates there must be tremendous benefits that far outweigh all of the obvious hazards and costs.

Emerging from research in the last 10 years is an unmistakable message: sleep is the single most effective thing we can do to reset our brain and body health each day. There’s no organ within the body or process within the brain that isn’t optimally enhanced by sleep (and detrimentally impaired when we don’t get enough).

Within the brain, sleep enriches a diversity of functions, including our ability to learn, memorise, and make logical decisions and choices.

Psychologically, sleep recalibrates our emotional brain circuits, allowing us to navigate next-day social and psychological challenges with cool-headed composure.

Physically, sleep restocks the armoury of our immune system, helping fight malignancy, preventing infection, and warding off all manner of sickness.

What happens when we don’t get enough sleep?

When we don’t get enough sleep, the consequences are grim and far-reaching. You can think of it as a broken water pipe in your home. It will leak down into every nook and cranny of your physiology.

If you already know the alarming consequences of sleep deprivation, I’d suggest skipping to “How does sleep work?”

The effects can be split into short-term and long-term, according to where they most commonly apply. But in reality, most of the short-term effects carry over to the long-term.

This list is not exhaustive, only a sample to demonstrate the level of biological damage caused by sleep deprivation.

Short-Term Negative effects‍

REDUCED MOTIVATION TO EXERCISE‍

When you are underslept, you are less likely to be physically active. When you convince yourself to exercise, you will generate less force pressure and reach physical exhaustion up to 30% faster.‍

INCREASED APPETITE‍

When you are sleep deprived, the brain receives a signal that is not dissimilar to starvation. It releases a cascade of hormones that change your appetite profile, so you’ll want to eat more. And you’re less satisfied after you eat food. When the body is sleep-deprived, the brain thinks, “Oh no, I must be under conditions of starvation… I must stay awake and forage for food.” This starvation signal increases a hormone called ghrelin (which makes you want to eat more), and it suppresses a hormone called leptin (which gives you a feeling of fullness).

When I read this, it didn’t surprise me. We can all remember a time that our diet went out the window when we were sleep-deprived.

Think about these first two factors together.

Overall, our hunger levels go up, we start to eat more. Now, we combine that with this lack of motivation to exercise, and we begin to understand how bad it can affect our physical health. We’re eating more, wanting to exercise less, and burning fewer calories because of it.

Remember this if you’re trying to lose weight.

INCREASED ANXIETY‍

One night of sleep loss can induce clinical anxiety in a person who doesn’t usually have it.

Further, this study found insufficient sleep was the strongest predictor of suicidal ideation, attempts, and completion.‍

REDUCED COGNITIVE PERFORMANCE‍

Moderate sleep deprivation produces impairments in cognitive performance equivalent to alcohol intoxication.‍

REDUCED WILLPOWER‍

Our prefrontal cortex is impaired by sleep deprivation, making us less likely to focus on work and get things done.‍

INCREASED RISK OF DRIVING ACCIDENTS THROUGH MICROSLEEPS‍

Drowsy driving accounts for more accidents on roads than either drugs or alcohol combined. Microsleeps are minor lapses where the eyelid will partially close. What’s found when this happens is that you no longer react. By comparison, drunk drivers or drugged drives swerve or break — there is at least generally a reaction. The micro sleeping person doesn’t respond, causing them to be much like a projectile missile.

REDUCED EFFECTIVENESS AS AN EMPLOYEE‍

This study found that employees who are sleep deprived select less challenging problems, produce fewer creative solutions to the problems they select, have an increased propensity to social loafing (slacking off and letting others do the work), and become less ethical.

REDUCED PHYSICAL ATTRACTIVENESS‍

This study looked at the perceived attractiveness of people in a rested state vs. a sleep-deprived state. It found the underslept picture was consistently rated as less attractive and more tired and sickly looking.

INCREASED MEMORY LOSS‍

This study found that any amount of sleep deprivation decreases the amount of memory we retain from the day.

INCREASED CORTISOL LEVELS, STUNTING PHYSICAL GROWTH‍

This study found that the body becomes much more driven by the sympathetic nervous system (the nervous system’s fight or flight branch ratchets up). This means more adrenaline is released, a high spike in cortisol levels (responsible for the stress response), and blunting of growth hormone.

Long-Term Negative effects‍

INCREASED RISK OF THREE OF THE TOP FOUR CANCERS‍

This evidence was so strong that the World Health Organisation classified night shifts’ as a “probable carcinogen.”‍

INCREASED RISK OF CARDIOVASCULAR DISEASEINCREASED RISK OF ALZHEIMER’S‍

Margaret Thatcher and Ronald Reagan both famously proclaimed the uselessness of sleep. They were proud enough to tell the world they only got 4–5 hours of sleep regularly. Is it a coincidence they both went on to develop Alzheimer’s disease?‍

INCREASED OF EARLY DEATH‍

If you take a group of people with the same age and compare short sleeping vs. those sleeping adequately, the people who are getting less sleep have a biological age higher than their chronological age.

REDUCED IMMUNE FUNCTION‍

This study found that sleep deprivation takes energy away from your immune system, making you more susceptible to disease.

These lists are scary, and I could go on, but I don’t need to. If you’ve read this far, it would be fair to say that you’re beginning to appreciate the importance of sleep.

So with that, let’s continue exploring how sleep works.

How does sleep work?

Humans have two stages of sleep:‍

The first is Non-REM. This is responsible for building muscle and bones, repairing and regenerating tissues, and strengthening the immune system. Non-REM has 4 sub-stages: 1, 2, 3, and 4. Stages 1 and 2 are the lightest sleep stages, while stages 3 and 4 are the deep restorative stages.

The second stage is REM, short for “rapid eye movement”, based on the abnormal horizontal shifting eye movements. REM is responsible for learning, memory development, and mood. It’s also known as dream sleep and is associated with increased brain activity.

Across the night, every 90-minutes, our brains cycle through Non-REM and REM sleep. It starts in Non-REM stage 1 and cycles through to stage 4 before moving on to REM. This usually happens four or five times over the night. This is where we get the standard recommendation for adequate sleep of 7–8 hours (5 cycles of 90-minutes each = 7.5 hours).

Source: Why We Sleep — Matthew Walker

‍Notice the “brief awakenings” that occur during or after REM sleep. This happens because the brain activity in REM sleep is most similar to when we are awake (high frequency).

The tendency for brief awakenings to align with REM sleep is why we wake up and immediately remember coming out of a dream.

Throughout the night, the ratio of Non-REM to REM within 90 minutes changes. In the first half, most of the 90-minute cycle is deep Non-REM, while in the second half, the majority is REM sleep. This means that if you get 6 hours of sleep (instead of 7.5 hours or 5 complete cycles), you’re losing 25% of total sleep but could be losing up to 70% of all REM sleep.

Why does this matter? It matters because studies in rodents (mice and rats) have shown that getting deprived of REM sleep shortens lifespans more than a corresponding reduction in Non-REM sleep. You may still feel rested after 6 hours, but you can’t account for the long-term damage you might be doing to yourself, missing one complete cycle of sleep and up to 70% of your REM sleep.

If you’ve never understood why finding results in rodents is significant, read this.

When should we sleep?

Two main factors determine when you want to sleep and when you want to be awake. The first factor is a 24-hour internal cycle called a Circadian Rhythm. It’s the human body’s equivalent of a 24-hour clock.

It regulates our internal systems such as sleeping and eating patterns, hormone production, temperature, alertness, mood, and digestion. In other words, it describes what our body naturally feels like doing at specific points throughout the day. A typical circadian rhythm looks like this:

Source: Sleep — Nick Littlehales

‍The second factor is a chemical substance called adenosine that builds up in your brain and creates “sleep pressure.” The longer you’ve been awake, the more the sleep pressure accumulates, and consequentially, the sleepier you feel.

It’s the combination of these two factors throughout a day that determines how alert you feel and when you feel tired or are ready for bed. As you wake up, adenosine is low but will increase in concentration for every waking minute. The longer you are awake, the more adenosine will accumulate. Think of it as a chemical barometer that continuously registers the amount of elapsed time since you woke up this morning.

Opposingly, as you wake, your circadian rhythm is ramping up to its peak, which generally occurs between 10 am-12 pm, depending on your sleep schedule. It will then start to descend throughout the afternoon and into the night as you prepare for sleep. This process repeats every 24 hours.

Source: Why We Sleep — Matthew Walker

A third factor, which you’re more likely to have heard of, is melatonin. Melatonin is a naturally occurring substance that regulates the timing of when sleep occurs by systematically signalling darkness throughout your body. To be clear, it doesn’t generate sleep. It simply gives a signal to the rest of the body to start preparing for sleep.

If sleep is a race, it can be thought of like the voice of a timing official. The timing official says, “Swimmers, on your mark,” and then fires the starting pistol that triggers the race.

That timing official, melatonin, governs when the race (sleep) begins but does not participate in the race.

In this analogy, the swimmers are other brain regions and processes that actively generate sleep. Melatonin corrals these sleep-generating regions of the brain to the starting line of bedtime.

Melatonin is produced when it’s been dark for long enough in our natural environment. As we discuss further below, this is why light regulation is essential in the overall sleep equation.

People often use melatonin supplements for jet lag or for getting back into a desirable sleep schedule. By using it, you’re telling your body that you’d like to start preparing for sleep.

Another critical but little understood factor in the overall sleep timing equation is chronotypes.

Your sleep chronotype simply means:

• Are you a morning person (25–30% of the population)? Morning people wake naturally, enjoy their breakfast and love the mornings. They tend not to need an alarm to wake them, and they’re less likely to feel fatigued during the day.
• Are you an evening person? (25–30% of the population)? Evening people like going to bed late. They’re partial to a nap in the daytime. They often skip breakfast and tend to sleep in on days off.
• Or are you somewhere in between? (the rest of us 40–50%)?

Most people have at least a vague idea of what their chronotype is. But you can find out by simply waking without an alarm for a week or so, allowing your body to tell you when it wants to be waking and when it’s had enough sleep. At the other end — night time — you need to listen closely to your body and when it’s telling you to go to sleep.

You can also use one of the below tests:

• Paid genetic test: 23andMe
• Free online survey: MEQ test or The Munich Chronotype Questionnaire — These have a decent agreement with genetic tests.

Once you’ve got a fair idea of what it’s most likely to be, change your schedule to accommodate it. Your sleep should start to improve.

The most important takeaway from understanding your chronotype is: don’t fight it. There is a significant degree of heritability in chronotypes. You might be able to wiggle it around by about 30-minutes from your natural rhythm, but any more than that, and you will start sacrificing sleep quality.

How much sleep do we need?

So, at this point, we understand why we sleep, what sleep involves, and what determines when we sleep. But how much sleep do we actually need? How do we know if we’re sleeping enough?

The short answer is: on average, 7–9 hours, or the equivalent of five complete 90-minute cycles of sleep. I don’t say precisely 7.5 hours (five complete cycles) because actual sleep time and time in bed are two different things. The exact sleep time needed for most people is 7.5 hours, but the necessary time in bed to get that sleep is highly variable. In other words, sleep efficiency, the percentage of time asleep relative to the amount of time in bed, is very different between people.

The longer answer is: it depends.

It depends on your genes and the quality of your sleep. There is no one-size-fits-all for sleep, just as there is no one standard height for children or adults. Some people can get by on 5 hours of sleep without feeling tired. Some need 10 hours.

The right amount of sleep is the number of hours needed for you to wake up feeling refreshed, not sleeping during the day, but then ready for bed at a regular bedtime, without difficulty dropping off. If you are achieving that regularly, if you are waking up before your alarm and not catching up on sleep when you have the chance at the weekend, then you’re likely getting enough hours of sleep.

Other questions you can ask are, “After waking up in the morning, could I fall asleep by mid-morning (10/11 am)?” If the answer is yes, you’re likely underslept. Another is, “Can I function optimally without caffeine before midday?”. If the answer is no, you’re likely underslept.

Now, I know many people who say they can get by on 6 hours of sleep per night. And there’s probably a small portion of those who can. But there’s likely something else at play here for the majority. Either chronic sleep deprivation has caused mental impairment to the extent they’ve forgotten what it feels like to be well-rested and buzzing on natural energy. Or, it’s because of cognitive dissonance. We tell ourselves that we’re okay and functioning correctly, even when we aren’t because we don’t like to admit that we might be wrong or doing harm to ourselves. This can happen because of hindsight or confirmation biases.

When you fight biology and evolution, the harsh reality is that you usually lose as sleep is one of the most conserved human behaviours across living organisms. And the way that you’ll know you’ve lost is disease or sickness, either acute (short-term) or chronic (long-term). To quote the great Liam Neeson, a lack of sleep will find you, and it will kill you at some point.

If you’re looking for some further aids to help understand whether you’re getting enough sleep, try these:

• Pittsburgh Sleep Quality Index (“PSQI”)
• Epworth Sleepiness Scale (“ESS”)

How to sleep better

The part we’ve all been waiting for. Let’s take our sleep to the next level.

When it comes to sleep, “failure to prepare is preparing to fail.” We have a personal responsibility in achieving regular high-quality sleep. What you do immediately before you go to bed directly affects your sleep quality and duration, while what you do after waking has significant consequences for the rest of your day (and the next night).

There is no single pill solution for high-quality sleep. The most effective approach is a broad one and will lead to much better results. That said, there are some things you can do that will have an outsized impact compared to others. These are the 20% of inputs that will lead to 80% of the results.

Before we begin, it’s important to mention that none of these tips alone will be sufficient for dealing with more severe sleep issues, such as insomnia, sleep apnoea, narcolepsy, or restless leg syndrome. For these issues, you should consult a physician immediately.‍

One interesting point to note is that contrary to popular belief, sleeping pills are horrible for you and don’t produce natural sleep.

Because of this, the current first-line treatment for insomnia is Cognitive Behavioural Therapy for Insomnia (“CBT-I”). CBT-I involves patients working with a therapist for several weeks to build a bespoke set of techniques to break bad sleep habits and address anxieties inhibiting sleep.

Don’t succumb to the long-term option of what feels like the easy option of taking sleeping pills; they’re literally killing you. Of course, taking sleeping pills in short bursts when critical is completely fine, but don’t make it a habit.

So with that small disclaimer, let’s get into the five most important factors for better sleep (The “80/20”). All of these are discussed in further detail in the additional factors for maximising sleep section.

Five Most Important Factors For Maximising Sleep Quality:

1. Consistency: Go to bed at the same time and wake up at the same time every day. Your body struggles to keep its circadian rhythm in check when you don’t stay consistent. If you’re choosing between the two to stay consistent, choose wake-time because it’s more important. Not to mention we usually have more control over it anyway.
2. Light: Get lots of darkness at night and make sure you get daylight during the first half of the day. Darkness triggers melatonin secretion, promoting sleep.
3. Temperature: Your core body temperature needs to drop by 2–3 degrees Fahrenheit (~1 degree Celcius) for you to get to sleep. Make sure your room is cool, or have a warm shower before bedtime. It brings blood to your extremities, cooling your core.
4. Wait until you’re tired: Don’t lie awake in bed. It trains your brain to be triggered by your bed and force you awake because you create a learned association. Think about it, you don’t sit at the table waiting to eat dinner. Why would you lie in bed waiting to fall asleep? The body knows when it’s hungry and sleepy — take note.
5. Avoid: Alcohol, naps (in the late afternoon), caffeine, large meals and beverages late at night.

Additional Factors For Maximising Sleep Quality:

PRE-BEDTIME (BEFORE YOU GO TO BED IN THE EVENING)

1. Go from Light to Dark

Switch off or dim most of the lights in your house starting 90-minutes before bed. Darkening your environment promotes melatonin secretion, which promotes sleep.

Avoid longer wavelength light (“blue light”). It puts the breaks on melatonin secretion more so than warmer coloured lights.

Tools:

• Flux on your Mac or PC and Nightshift/Mode on your IOS or Android
• Himalayan Salt Lamps
• ‍‍TrueDark Blue Light Blockers

2. Go from Warm to Cool

Your core body temperature needs to decrease by 2–3 degrees Fahrenheit (~1 degree Celcius) to initiate sleep.

Having a hot shower before bed will bring the blood to the surface (your skin). When your surface is warm, it dumps all the heat from your body’s core, making you cooler.

Tools:

• Wear appropriate clothing
• Keep bedroom at 65–68 degrees Fahrenheit (18–20 degrees Celsius)
• Chilisleep — ChiliPAD or Ooler‍

3. Relax

In the last hour before bed, find a wind-down routine that involves at least one of three activities: Meditation, Relaxation, or Journalling.

Tools:

• Meditation — lowers your heart rate and activates the parasympathetic nervous system (responsible for relaxation).‍
• Journalling — helps ‘download’ your day and remove ruminating thoughts
• Light stretching — promotes relaxation‍
• Acupressure Spike Mat — promotes relaxation

4. Avoid Mental Stimulation

Things that cause stress and anxiety (emails or social media) make you ruminate over negative thoughts and release cortisol (stress hormone), promoting wakefulness. Avoid these activities for at least one hour before bed.

5. Avoid Caffeine 12 hours Before Bedtime

Remember the sleep chemical called adenosine that builds up sleep pressure, making you feel tired? Caffeine works by battling with adenosine to latch onto adenosine receptors (like the lock that a key enters) in the brain. By occupying these receptors, caffeine blocks the sleepiness signal generally communicated to the brain by adenosine.

Caffeine has a half-life on average for most people of about 6 hours and a quarter-life of 12 hours. In other words, after 6 hours, 50% of the caffeine is still in your brain, and, after 12 hours, 25% of the caffeine is still there.

It’s worth noting that not all people are affected equally by caffeine. But if you are one of the people it does affect, make sure to avoid drinking caffeine at least 12 hours before you go to bed.

6. Avoid Alcohol Too Close To Bedtime

Many people believe alcohol helps them fall asleep more quickly or even offers higher-quality sleep throughout the night. Both of these beliefs are untrue.
Alcohol does three things to sleep:

1. It’s a sedative, so it works like sleeping pills. That is, it doesn’t induce natural sleep. The electrical brainwave state you enter via alcohol is not like natural sleep; instead, it’s akin to a light form of anesthesia.
2. It fragments sleep, making you wake up many more times during the night, often so brief that you don’t remember, but they impact your physiology.
3. It blocks REM sleep and keeps you in the lighter stages of sleep. You wake up feeling unrefreshed and unrestored.
   As with caffeine, alcohol impacts people differently. For some, the stress release from a drink or two might outweigh any potential impact on your sleep. Find out what works for you.

7. Avoid Naps During The Day

If you find it hard to sleep at night, do not nap during the day — especially in the late afternoon. Adenosine builds up in your body beginning when you wake up. The more that builds up, the sleepier you feel. After ~16 hours, you should have enough to fall and stay asleep. During a sleep (nap), the brain will clear adenosine away. This makes it harder to fall asleep at night because you’ve released the valve on the pressure cooker of sleep.

The same rule applies if you’ve had a shitty night sleep and feel as though you need to nap. Resist the temptation to do so. You’ll thank yourself when you’re getting into bed that night.

All that said, if you can nap regularly and are still able to fall asleep at night, naps are fine.

8. Avoid Exercise 2–3 hours Before Bedtime

Exercise during the day is great because it’s been shown to build sleep pressure (adenosine). However, make sure the latest you exercise is 2–3 hours before you go to bed. This will ensure your body temperature and heart rate have time to lower, both critical biological changes that allow your body to sleep.

9. Understand The Associative Strength Of Your Brain

Your brain is an incredibly associative organ. It learns to associate things in a “Pavlovian way” (external cue triggers internal response).

If you lie in bed awake, it will very quickly learn that your bed is a place for being awake, not being asleep. Further, if you read, spend time on your laptop/iPad, or do any other activity, not including sleep, it will associate your bedroom with that. This negatively impacts your sleep.

Break the associations. Keep your bedroom only for sleep. If you are struggling to fall asleep, go to another room, dim the lights and read a book.

Remember: you wouldn’t sit at the table waiting to get hungry, so stop lying in bed waiting to get sleepy.

10. Avoid Large Meals 3 Hours Before Bedtime

Eating late can cause acid reflux or digestive issues. Further, it can raise your core body temperature, making it more difficult for you to fall asleep.

Make sure to avoid drinking large amounts of fluids before you sleep. It will cause you to wake during the night to go to the toilet or remain in a shallow state of sleep. Both will ruin the quality of your sleep.

11. Trial Supplements

There is yet to be any solid scientific evidence indicating that supplements such as magnesium or chamomile tea promote deeper sleep. However, anecdotally, many people have spoken of magnesium’s positive effect in promoting relaxation in the body and muscles. Once there are promising scientific studies completed, we may find it helpful.

Until then, we should remember the placebo effect is one of the most reliable effects in all of pharmacology. If you think a supplement gives you better sleep quality, it probably is, and there’s no harm in taking it.

BEDTIME (WHEN YOU’RE IN BED)

1. Comfort (Sheets/pillow/mattress/body position)

Use Hypoallergenic and breathable bedding to keep out potential impediments to sleep and regulate your body temperature. I use Mellani.‍

Use fresh sheets 2x per week. A lot of sleep is psychological. Using fresh linen is psychologically enticing — think of that feeling you get when you get into a new hotel bed.

There is no specific prescription for a pillow. You need to find one that’s ergonomically effective for you. This is a process of trial and error.

How to find your ideal mattress

1. The ideal mattress shouldn’t have any gap between your head and the bed (even without a pillow).
2. The bed’s material isn’t what matters. What matters is that the mattress takes your entire body weight with ease, such that it gives you the sensation that you don’t need any pillow to sleep with.
3. Your vertebrae should be in line, so there’s no pressure building up.
4. Size matters, particularly when you have a partner. Buy as big as you can.

Body position‍

1. Your optimal body position is whatever feels most comfortable for you. There’s no firm evidence indicating an optimal choice. If you’re already comfortable, don’t force a change.
2. If you suffer from sleep apnoea/heavy snoring, it’s best to not sleep on your back. When you sleep on your back, you’re more likely to snore because it relaxes your throat, causing a narrowing of the airways.
3. 45% of people sleep on the non-dominant side of their body in the foetal position. This is likely because it creates an unconsciously safe psychological state where you’re protecting your genitals and heart with your dominant hand.

2. Temperature

As discussed above, keep your bedroom at 65–68 degrees Fahrenheit (18–20 degrees Celsius) for optimal sleep.

3. Sleeping With A Partner

There is a certain stigma associated with not sleeping with your partner at night. That is, people seem to believe that if you’re not sleeping together well, you’re not having sex, and your relationship is suffering as a result.

Counterintuitively, this isn’t the case. By having a sleep divorce, you increase the quality of your sleep. Better sleep quality leads to a better mood. A better mood leads to improved interpersonal relationships (more patience, more energy for each other).

Luckily for us, there’s a way we can get the best of both worlds. When we think about sleeping with a partner, we generally think about the ‘bookends’ of sleep. That is sex in the evening and a cuddle in the morning — or vice versa.

We can retain these ‘bookends’ by creating an evening and morning routine where we go into the bedroom together when the first person likes to go to bed. We ‘hang’ out and say goodnight to each other. The 2nd person then goes to a separate room. Then in the morning, we reverse engineer the same trick. In this way, we’re able to get 99% of co-sleeping benefits without the need to sleep next to each other.

4. Sound Disruption

This one is obvious. Limit exposure to sounds that could cause you to wake during sleep. Wear earplugs if necessary.

5. Darkness

This one should also be obvious by now. Keep your room as dark as possible. Use blackout curtains if necessary.

6. Remove All Clock Faces From Your Room

Knowing that it’s 3:35 am in the morning is only going to trigger more anxiety. The same goes for your phone: keep it on the other side of your room, so you’re not tempted to check it during the night.

POST-BEDTIME (WHEN YOU WAKE-UP IN MORNING)

A good night sleep begins when you wake up in the morning. A post-sleep routine will help you move from a sleep state to a fully awake state effectively.

1. Go from Dark to Light

This is another side of the light coin discussed in the pre-bedtime routine. Instead of reducing light before bedtime, we want to increase it. This raises our alertness, helps set our body block and allows us to make the final hormone shift from melatonin to serotonin.

The easiest way to action this is to open your curtains, turn up your lights or go outside into daylight in the morning. If you want to go a step further, you can look at a Dawn Light Simulator.‍

2. Limit Anticipatory Anxiety

Devices and technologies cause what’s called anticipatory anxiety. When you wake up in the morning, and the first thing you do is check your phone (Emails, texts, social media, etc.), you’re essentially training your brain to anticipate that wave of anxiety every morning.

This anticipatory expectation in the morning lessens the amount of deep sleep you get and keeps you in a shallow state. The greater the anxiety that there is coming in the following day, the greater the reduction in deep sleep you have the night before.

The ultimate form of anticipatory anxiety comes when you have an important event you can’t miss in the morning — a meeting or a flight to catch. Have you ever experienced this yourself? Lying in bed, eyes wide open, heart beating out of its chest. The same thing happens when you check your phone first thing in the morning, only on a lesser scale.

3. Eat Breakfast To Set Your Biological Clock

Eating time is the second most important indicator that your circadian rhythm (biological clock) uses to regulate itself.

When you eat breakfast in the morning, you’re essentially telling your body that it’s time for wakefulness.

Eating first thing further reinforces the impact of a consistent wake time and will help your body retain a regular schedule.

4. Limit Artificial Awakenings

This one is wishful thinking, but if you can avoid using an alarm clock, it will be constructive for your sleep.

Alarm clocks increase anticipatory anxiety and prematurely end sleep. This isn’t what Mother Nature intended.

There’s a lot here. Remember the most important: Consistency, light, temperature, don’t lie in bed awake and avoid alcohol, caffeine, and large meals.

What is on the horizon for sleep science and technology?

Before we discuss the horizon, let’s discuss the current status of sleep technology. In summary, wearables like Oura and Fitbit are:‍

Best at: Estimating the total duration of sleep, body temperature, heart rate variability, and heart rate‍

Decent at: Determining where you’re in an awake state, non-REM, and REM‍

Worst at: Estimating your time split between the 4 stages of sleep

The lack of complete accuracy in these devices will be fixed over time, but for now, what’s most important is that they allow you to track trends and relative changes. Once you establish a baseline and see a deviation from that baseline, the deviation is likely an actual deviation rather than a technology problem. This is because the technology, even though it may not be completely accurate, it’s consistently inaccurate. This means that variance from a baseline can actually tell you a lot.

For example, using my Oura ring, I can clearly see the impact that alcohol has on key sleep metrics. These include an elevated resting heart rate, elevated respiratory rate, lower heart rate variability (“HRV” — the higher your HRV, the lower your physiological stress), and a higher core body temperature.

THESE ARE TWO REGULAR NIGHTS OF SLEEP:

Night 1:

Night 2:

Notice on both of these nights resting heart rate is 40 bpm, HRV is >75 ms, body temperature is lower than average, and respiratory rate is <13.2 / min.

Now, look at the Sunday in between these two nights.

Resting heart rate is up ~50% on average, HRV is down over 100%, body temperature is almost 1 degree higher than usual, and respiratory rate is up 2 full breaths per minute.

The effect of alcohol is undeniable here.

This is valuable information, and any Oura user will tell you a similar story. These days, I’m hyper-aware of alcohol’s effect, making me much more selective when I do indulge because I know it will be at the expense of a good nights sleep. As the old saying goes, “What gets measured, get’s managed”.

So, current wearable devices aren’t perfect yet, but that doesn’t mean they’re not helpful because they allow us to track trends and relative changes.

What’s most exciting is what’s on the horizon. Matthew Walker discusses two potential ideas he would like to see in the next 5–10 years in his book, “Why We Sleep”.

Idea #1 — Personalised sleep medicine

This involves a technology capable of ingesting every piece of data about you (that you authorise):

1. Bio-tracking data about your physiology
2. Data about your mental state
3. Data out of your calendar such as, what you’ve been doing, what you’re doing today, and what you’ve got upcoming in your future (e.g., it will know if you’ve got a trip coming up that involves travelling through time zones)

After ingesting all of that data for each specific day and evening, it would create a personalised, tailored sleep prescription for you.

It would advise you on:

1. The best things for you to do today for your sleep
2. When you should be doing them
3. How much of them you should be doing
4. When you should be going to bed and aiming to wake

When you go to bed, the technology will interact with a closed-loop technology that modulates your sleep environment (light exposure, temperature, and wake time). Further, the system could help inform eating times, light intake, and temperatures within your home.

The idea is that it’s a fully personalised sleep coach that helps you get as close as possible to a perfect sleep schedule.

Idea #2 — Predictive Analytics‍

Predictive Analytics uses data, statistical algorithms and machine learning techniques to identify the likelihood of future outcomes based on historical data. The goal is to provide an assessment of what will happen in the future.

Predictive analytics has often been used in behavioural change to shift people away from detrimental behaviours.

For example, if you have a smoker, you can show them how they will look 10, 20, or 30 years with a continued habit. You can show them how their teeth will look or their skin.

You can show them how it will affect their likelihood of certain diseases such as cardiovascular disease. Then, on the contrary, you can show them how these things will change with reduced exposure. The idea is that with a tangible, vivid description of the health benefit of quitting a poor habit, you can influence a person to stop making the habit.

Matthew Walker would like to see something similar done with sleep.

For example:

If you were to continue sleeping only 5 hr/night, here are your disease trajectories (i.e., Alzheimer’s, mental health, heart disease, cancer, etc.)

But if you increase your sleep time to 7.5 or 8 hrs/night, here’s how those things will change.

The person would also be offered simple suggestions to help them adapt (e.g., light exposure, bedtime alarm)

These advancements would be exciting and take a lot of the thinking away from maximising sleep quality. But for now, the responsibility for a good night’s sleep is well and truly ours, and luckily, there’s a lot we can do to control it.

If you have further questions about sleep, don’t hesitate to reach out! This will be an evergreen piece of content and continually updated as we receive new and better information.