Get Enough Good Quality Sleep

Why should you care about sleep?

Sufficient sleep of good quality [1] is a non-negotiable part of a long and healthy life and provides a vital daily reset for brain and body health. Sleep is essential because it:

• Consolidates memory
• Clears brain waste [2]
• Regulates emotions
• Strengthens the immune system
• Manages metabolism.

For me the definitive piece of reading on sleep is the book Why We Sleep by Matthew Walker, and I can’t recommend it enough.

Sleep science essentials

In this post I really focus on the variety of techniques I use to improve my sleep quality and duration rather than diving into the science behind sleep. However, there are some essential concepts that are worth understanding so that the tips make more sense. In addition, this post finishes up with some resources you can use to start to broaden your understanding of what happens when you sleep.

The circadian rhythm

Your circadian rhythm is your internal, biological near-24-hour clock that cycles between sleepiness and alertness but is also involved in a wide range of other biological processes. This ‘master clock’ is situated in a tiny region of the brain called the Suprachiasmatic Nucleus (SCN) which receives direct signals from your eyes. When it senses light (in particular key blue light frequencies from the sun), it tells the brain to stay alert and conversely, as light fades, it signals the production of melatonin to promote sleepiness.

Even without the trigger of light, your circadian rhythm will still follow a 24-hour cycle but will slowly drift away. Anything that puts your internal clock out of sync with the external rise and fall of the sun (e.g., jet lag or shift working) disrupts the smooth operation of that circadian rhythm. Thus, maintaining consistent bedtime and wake times coupled with bright light upon waking and dim light at the end of the day will help to reinforce your circadian rhythm and promote good sleep.

Key hormones involved in sleep

Melatonin: As daylight fades, the retina of the eye sends signals to the brain to start the production of the hormone melatonin (primarily in the pineal gland). As melatonin levels rise, body temperature and blood pressure fall, preparing the body for sleep and acting like a biological ‘dimmer switch’ to manage the circadian rhythm. Conversely, light exposure (e.g. when the sun rises) inhibits melatonin production which helps to wake you up. Anything that interferes with melatonin can make it harder to feel sleepy. For example, melatonin inhibts insulsin (to keep blood sugar stable whilst you fast overnight) but eating late forces the body to produce insulin when it’s trying to shut that system down, which causes metabolic “noise” that disrupts sleep.

Adenosine: If you think of melatonin as telling us “it’s dark” adenosine is telling us “it’s been a while since you slept”. Melatonin is about light and adenosine is about time [3]. The longer you stay awake, the more adenosine builds up in the brain, starting from the moment you wake. The rise in adenosine creates a ‘sleep pressure’ and when it reaches a certain level, it triggers the urge to sleep. Adenosine is a by-product of the body using ATP (adenosine triphosphate) for fuel, and thus can be thought of as a tracker for how long you have been awake. Whilst you sleep (specifically in the slow wave (deep sleep phase), adenosine is cleared from the brain and, by morning, levels are at their lowest ready for the cycle to start again. If you get enough sleep but very little deep sleep, you may well still feel ‘groggy’ due to residual adenosine. Caffeine works by blocking the adenosine receptors in the brain (since it has a similar molecular structure to adenosine). It is thus truer to say that caffeine prevents you from feeling tired rather than giving you energy.

Cortisol: If you think of melatonin as a dimmer switch for your brain, then cortisol (often thought of as the ‘stress’ hormone) is the opposite and acts more like an alarm clock, kick-starting your system for the day. Cortisol levels should be at the lowest around midnight and begin to increase 2-3 hours before you wake up. Immediately upon waking (and especially when light hits your eyes) there is large spike in cortisol which makes you feel alert, increases blood sugar for energy and resets your circadian clock for another day. Cortisol levels should then decrease through the day, dropping significantly by sunset allowing melatonin to take over. However, if cortisol levels remain high (e.g due to chronic stress) the brain remains aroused and sleep is much more difficult. This can create a vicious cycle as a bad night’s sleep causes stress and higher cortisol levels the next day leading to more trouble sleeping the next night.

Of course, a wide range of other hormones and chemicals are involved in sleep, and you might like to read up on some of the following:

• GABA (Gamma-Aminobutyric Acid): Reduces brain activity to keep you asleep.
• Orexin: Keeps you awake and alert.
• Histamine: In the brain this acts as a stimulant.
• Growth Hormone: Secreted during deep sleep and is essential for tissue growth and repair.
• Leptin & Ghrelin: Involved in managing hunger.

The stages of sleep

Your brain goes through a number of different stages of sleep during the night and these stages, the time spent in each, and the reptitive cycle between them is often referred to as your ‘sleep architecture’.

There are two distinct types of sleep which you cycle between

• Non-REM (Non-Rapid Eye Movement)
• REM (Rapid Eye Movement)

A full cycle takes around 90 minutes, and you repeat this multiple times in the night. NREM sleep is itself broken down into 3 distinct stages which gives us an overall set as follows:

• Stage 1 – Transition to Light Sleep: This is where you are ‘dozing off’ and can easily be awoken. This stage lasts only a few minutes
• Stage 2 – Light Sleep: This is where you spend the largest amount of sleep time (about 50% of sleep) and its function is memory consolidation.
• Stage 3 - Deep Sleep also called Slow Wave Sleep (SWS): This is the most restorative sleep phase (about 25% of sleep). Its function is physical repair and growth. You get most of your deep sleep in the first half of the night.
• Stage 4 – REM Sleep: This is the phase of sleep where you dream and is characterised by rapid eye movements and paralysis (to stop us acting out our dreams). You spend about 25% of sleep in this phase and, as the night goes on, the phases of REM last longer, with the longest coming in the hours before awakening.

It’s thus crucial to think not only of the number of hours sleep you get but also how much you spend in each stage - which is exactly where a good quality sleep tracker is invaluable.

How to get great sleep

I’ll be straight up – until recent times my sleep has been appalling – both in terms of the attention I paid to it and the actual amount of quality of sleep I got. I’ve grappled with occasional bouts of insomnia most of my adult life and often worked late into the night, only getting minimal amounts of sleep before starting again the next day.

I decided to try and tackle my sleep during a particularly unpleasant period of insomnia, and it took an absolute battery of techniques, all in combination, to bring it under control.

Here’s the recipe of techniques that I use to get a good, restorative night’s sleep. It’s still far from perfect, but the general trend shows I am improving.

• Use a sleep tracker to give insight into how much sleep you are getting and the relative proportions of light, deep and REM sleep that make up your night’s sleep. I use Whoop but there are many other options out there. Your wearable might not be totally accurate in terms of discerning between sleep and lying very still and may also not discriminate well between the various phases of sleep. However, the good ones (Whoop, Oura, Apple Watch, Ultrahuman, Happy Ring, Eight Sleep, etc) will be ‘consistently inaccurate’ and thus are useful for showing long-term trends and monitoring improvements in sleep duration and quality even if they are not completely accurate on any given night.
  
  
• Go to bed at the same time every night and get up at the same time every day aiming for around 8hrs of sleep [1]. That consistency of schedule anchors your circadian rhythm and gives a consistent signal to your master clock, which then coordinates the biological processes in your body. If you can’t anchor both your sleep and wake time, then at the very least anchor your wake-time (with weekends and weekdays the same) and get bright light (see below) straight away.
  
  
• Don’t eat your last meal of the day (especially if it is high in carbohydrates) any later than 3hrs before you sleep [4]. The sugar spike after the meal (and the knock-on rise in insulin) can disrupt the release of melatonin. In addition, the consequent sugar crash in the middle of the night triggers a hormonal surge (cortisol and adrenaline) to release stored sugar which can leave you wide awake and alert in the middle of the night. See my post on Continuous Glucose Monitoring for how you can gain insight into how your diet and meal schedule affects your blood sugar during the night.
  
  
• Or, consume all your food for the day by later afternoon[4]. I found that all the other actions enabled me to fall asleep at night, but it was only this one that stopped me from waking for good at around 3am — by shifting my time restricted eating window to between 10:00 and 16:00. I still sit down with my family for dinner in the evening because that’s really important to me – but all my eating is done earlier in the day.
  
  
• Get bright natural light in the morning and during the day [5]. This is very challenging for me with my schedule and with living in an often rainy and dark country. So, I use Ayo light therapy glasses for 30 mins in the morning. These are better than many ‘SAD lamps’ because although they have a lower intensity they focus in on the part of the spectrum that your circadian rhythm is most receptive to. In addition, because you wear them I can get your morning dose whilst going through my chores or even whilst doing some exercise. Much more practical for me than trying to sit 18 inches way from a lamp for 30 minutes!
  
  
• Avoid caffeine after midday and avoid caffeine completely if you are particularly sensitive to it [6].
  
  
• Avoid alcohol or narcotics (e.g., cannabis). Although they may make you feel sleepy, they will disrupt the architecture of your sleep leading to poor quality sleep. You might get enough hours, but it won’t be the right kind of sleep [7] [8].
  
  
• Avoid sleep tablets [9] for exactly the same reason. However, there is a new class of sleep medications (DORAs - Dual Orexin Receptor Antagonists) that may offer a more natural approach which you might like to discuss with your doctor if you suffer badly with insomnia.
  
  
• Avoid mobile phones, tablets and laptops in the 2 hours before settling down to sleep (partially because of the light from them but more because of the mental stimulation they cause) [10].
  
  
• Keep the house lights as low as possible for the last couple of hours before bedtime [11]. This is something I’ve been unable to achieve given the practicalities of a busy family household. But, as with bright light in the morning, you are trying to anchor your circadian rhythm and maintain the natural day/night cycle that humans evolved with.
  
  
• If you do read in bed before going to sleep, then use a red light/dim light. For the same reason as with the house lights, I use a small pencil light which clips onto my book and find this one great.
  
  
• Keep the room cool and dark throughout the night [12] and if (like me) you live in a busy household, then a high-quality eye mask is invaluable. I’ve tried loads and finally found and love the Manta Pro.
  
  
• Use ear plugs [13] to block out noises that could wake you up, especially if you sleep in the same room as your partner. Again, I’ve tried many and Loop Dream are the standout winners for me
  
  
• Use noise-cancelling headphones [13] if noise is a real problem (it is for me as my partner snores heavily but I am determined that we sleep in the same bed together). I use Bose QuietComfort which I wear on top of the Loop ear plugs. As I’m a side-sleeper, a great hack I came across is to use a neck travel pillow on top of your pillow and nestle the bulky headphone on your ‘down-side’ into the hole in the middle.
  
  
• Use white or brown noise [13], stories (e.g., the Calm App) or music specifically engineered to promote sleep (e.g Brain.fm). Personally, I love the MyNoise App and with the combination of brown noise, Bose headphones AND Loop ear plugs, I can fully control my environment and sleep in the same bed as my partner.
  
  
• Get up and go and read in another room (using a dim red light) if you cannot fall asleep within 30 minutes or wake up in the night for longer than 30 minutes. Don’t return to bed until you feel sleepy. By doing this you are trying to break the mental association of your bed as a place where you don’t sleep.

Further sources of information

The Examine web site for independent, unsponsored meta-analyses of health research

The Sleep Foundation’s web site

Why We Sleep by Dr Matthew Walker

Matthew Walker on the Diary of a CEO podcast

References

[1] Watson NF, et al. (2015). Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement. Journal of Clinical Sleep Medicine.

[2] Xie L, et al. (2013). Sleep drives metabolite clearance from the adult brain. Science.

[3] Borbély AA. (1982). A two process model of sleep regulation. Hum Neurobiol.

[4] McHill, A. W., et al. (2017). “Later circadian timing of food intake is associated with increased body fat.” The American Journal of Clinical Nutrition.

[5] Blume, C., et al. (2019). “Effects of Light on Human Circadian Rhythms, Sleep and Mood.” Somnologie.

[6] Drake, C., et al. (2013). “Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed.” Journal of Clinical Sleep Medicine.

[7] Ebrahim, I. O., et al. (2013). “Alcohol and Sleep I: Effects on Normal Sleep.” Alcoholism: Clinical and Experimental Research.

[8] Gates, P. J., et al. (2014). “The effects of cannabinoid administration on sleep: a systematic review of human studies.” Sleep Medicine Reviews.

[9] Riemann, D., et al. (2015). “Adverse effects of sleep-promoting medication on sleep architecture.” Sleep Medicine Reviews.

[10] Gradisar, M., et al. (2013). “The Sleep and Technology Use of Americans: Findings from the National Sleep Foundation’s 2011 Sleep in America Poll.” Journal of Clinical Sleep Medicine.

[11] Gooley, J. J., et al. (2011). “Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans.” The Journal of Clinical Endocrinology & Metabolism.

[12] Okamoto-Mizuno, K., & Mizuno, K. (2012). “Effects of thermal environment on sleep and circadian rhythm.” Journal of Physiological Anthropology.

[13] Zhou, J., et al. (2012). “Acoustic effects on sleep patterns based on EEG multi-step analysis.” Scientific Reports.