Lever #1: Sleep
An overview of sleep, its four sub-levers, and simple practices for better sleep.
“Here’s a Gedanken [thought experiment]. Let’s say you eat well, you exercise regularly, and you get adequate sleep. I’m going to take one of these strengths of yours away. Either your diet, your exercise regimen, or your sleep is going down the toilet. There’s a catch: I’m allowing you to designate one of the three as untouchable. Which one do you guard? If I had to choose one to save, it would be sleep. Not even close.”
– Peter Attia, M.D.
Health Detriments from Poor Sleep
“Every disease that is killing us in developed nations has causal and significant links to a lack of sleep.”
– Matthew Walker, Professor of Neuroscience & Psychology at the University of California, Berkeley
As a society, the importance of a proper sleep regimen and the negative health impacts of poor sleep hygiene has, at large, eluded us. We have even seen subcultures emerge praising those who sleep less in favour of long nights spent at the office.
Matthew Walker, Professor of Neuroscience and Psychology at the University of California, Berkeley, and Founder and Director of the Center for Human Sleep Science, argues in his book titled Why We Sleep that there is a causal link between sleep deprivation and depression, heart disease, cancer and Alzheimer’s. The definition of inadequate sleep being less than seven hours per night on a consistent basis.
Furthermore, neglecting sleep sabotages your creativity, problem-solving, decision-making, learning, memory, heart and brain health, emotional well-being, and immune system, and has the potential to shorten your overall lifespan. The bottom line is that sleep is the most important factor in our health and we need to start treating it as such.
Benefits of Sleep
The benefits of sleep, some noticeable and others not, range from improved memory and motor task proficiency (muscle memory) to enhanced creativity and problem-solving, reduced stress, and an improved mood.
Many other benefits can be seen as preventative.
In other words, you won’t know you’re not getting enough sleep until you have developed an illness or disease resulting from, or contributed to by, poor sleep practices. These include getting sick less often, staying at a healthy weight (which is essential to fighting off a bounty of diseases ranging from heart disease to cancer), lowering risk for health problems such as diabetes, and avoiding injuries that come from a lack of sleep.
Scientifically, sleep produces complex neurochemical baths that improve our brains in numerous ways. It bolsters our immune system, battles malignancy (meaning it thwarts medical conditions from becoming progressively worse), prevents infection, and staves off all manner of sickness. In short, sleep enhances our evolutionary fitness, just in many ways we can’t see.
The Four Sub-Levers of Sleep
When designing a sleep schedule and building positive sleep habits, there are four levers we can pull to optimize and improve our sleep quality.
Duration. The number of hours we sleep each night. Aim for a minimum of 7 hours but, if possible, go for a full 8 hours per night.
Regularity. The consistency of our sleep schedule. Ideally, we’re going to bed and waking up at the same time, seven days per week.
Depth. There are two basic types of sleep: Rapid Eye Movement (REM) and non-REM sleep. We’re aiming for 20-25% of our sleeping hours to be REM sleep as this is when areas of the brain essential to learning and memories are stimulated. Additionally, REM sleep is necessary for feeling rested and staying healthy.
Continuity. The number of times we wake up each night. The lower, the better.
Looking at the four levers above, it becomes apparent that we only have direct control over two, duration and regularity, whereas the other two, depth and continuity, seem to be out of our control.
However, we can manipulate these factors by putting routines into place that will improve our overall sleep quality. The last section of this article outlines simple practices for better sleep.
The Science
Sleep is the result of a tango between the three hormones cortisol, melatonin, and adenosine. At a chemical level, low cortisol, high or rising melatonin, and high adenosine are what we’re aiming for to achieve high-quality sleep.
Cortisol is widely known as the stress hormone which, surprise surprise, is not conducive to high-quality sleep if elevated. Our bodies have a natural cycle for cortisol. Ideally, our cortisol levels are low upon waking, hit their high point for the day roughly two hours after getting out of bed, and then taper off the rest of the day until they reach a similar level to when we woke up. Minimizing cortisol is a lengthier topic so for now, we can apply logic to minimize cortisol spikes near bedtime. Avoid conversations or activities that cause you stress or anxiety, calm your mind by avoiding confrontations, read (preferably fiction), meditate, journal, do something kind, or tell someone you love them. It’s hard to spike cortisol if you’re coming from a place of calm, love, and joy.
Melatonin, widely known for its over-the-counter applications, is referred to as the sleep hormone. It’s secreted from a tiny gland, called the pineal gland, and is ideally elevated by the time we are getting into bed. Modern technology has greatly impeded our pineal gland’s ability to do its job as we are constantly exposed to blue light. Whether it be from our mobile phones, tablets, computers, or laptops, it's near impossible to escape blue light exposure which has a “WAKE UP!” effect on our brains. Our primal hunter and gatherer ancestors, who slept outdoors, awoke with the sunrise and slept with the sunset as the natural darkness signaled to their brains that it was time to remove the breaks of consciousness. The obvious and most optimal solution to this issue is to stop looking at blue light-emitting devices at least one hour before bed. In today’s world, that is much easier said than done. As a society, we are greatly dependent on and highly addicted to our screens. Myself included. Beyond that, many of us use television or video games as a way to wind down or decompress after a long day. Luckily, where modern technology created blue light exposure, it also created a way to block most of it out. Wearing blue-light-blocking glasses if exposed to blue light within one to two hours of bedtime will help your pineal gland in melatonin secretion and thus improve your overall sleep quality.
Adenosine, although less widely known, may sound familiar from a Grade 10 biology class on adenosine triphosphate (ATP) which is the primary carrier of energy in human cells. As a compound of its own, adenosine should be at high levels for ideal sleeping conditions. Adenosine levels rise as energy is expended throughout the day, so naturally, levels will be higher at night than in the morning. Exercise actively increases expended energy which contributes to higher adenosine levels at night, leading to better quality sleep. Remember that spill-over I mentioned in The Longevity Framework? There’s example numero uno. Interestingly, caffeine works by blocking adenosine receptors and thus limiting our ability to increase adenosine levels. So, in addition to a regular exercise routine, cutting off caffeine consumption by 1pm will also aid in improving sleep quality.
In summary, here’s how we optimize sleep at a molecular level:
Low cortisol. Use common sense or the suggestions above to minimize stress near bedtime.
High or rising melatonin. Eliminate or minimize blue light exposure within one hour of your scheduled bedtime or, if unavoidable, use blue light blocking glasses.
High adenosine. Exercise on a daily basis and cut off caffeine consumption by 1pm.
Sleep Hygiene: Simple Practices for Better Sleep
"I think that sleep may be one of the most significant lifestyle factors that determines your risk ratio for Alzheimer's disease."
– Matthew Walker, Professor of Neuroscience & Psychology at the University of California, Berkeley
Keep a consistent sleep schedule. Sticking to a consistent schedule reinforces your body’s sleep cycle and helps to reduce daytime sleepiness. A perfect schedule would consist of the same number of hours per night, ideally eight, with the same wake-up time and bedtime seven days a week.
Optimize your sleep environment. Replace any LED bulbs in your bedroom as they emit the most sleep-corroding blue light. Instead, use an incandescent bulb or a specially designed low blue light bulb. Set your thermostat to drop your bedroom’s temperature to 18 degrees Celsius (65 degrees Fahrenheit) by your scheduled bedtime. This will help decrease your core temperature by 2-3 degrees Fahrenheit which plays a key role in initiating sleep. To regulate your body temperature while sleeping in warmer climates consider using a Chilipad. Additionally, setting your thermostat to rise during the last 15 minutes of your sleep will make it easier to get up and reduce grogginess.
Avoid blue light-emitting devices before you go to bed. Use blue-light-blocking glasses if you’re planning to be on a screen within one hour before bed. This improves melatonin secretion which plays a central role in helping us sleep.
Exercise daily and cut off caffeine consumption by 1pm. These habits help build adenosine levels within our bodies. Higher adenosine equals better sleep.
Reconsider your sleep position. If you snore heavily or suffer from sleep apnea, it is likely best to avoid sleeping on your back. Otherwise, sleeping on your back is best for spinal alignment. However, if you’re comfortable in your current sleeping position, don’t force yourself to change positions as there is not yet solid evidence that any particular sleeping position (back vs. side vs. stomach) produces better sleep.
Get a sleep divorce. A sleep divorce from your partner could enhance the quality of your sleep which, despite initial concerns over losing intimacy, means improved sex hormones in both males and females translating to an improved physical relationship and improved intimacy.
Have sex. Studies show that for 60% of women and 70% of men, sex resulting in an orgasm contributes to higher-quality sleep. This is attributed to the deceleration of your heart rate post-intercourse and a corresponding drop in cortisol.
Don’t worry. Try to avoid emotionally upsetting conversations and activities before your scheduled bedtime. Don't dwell on or bring your problems to bed. Daily mindful meditation practice has proven to be one of the most effective ways to improve distress tolerance which allows us to better manage actual or perceived emotional distress.
Consider napping. The benefits of napping include improved learning and memory as well as cardiovascular function. However, naps will also release some of the adenosine you have built up throughout the day which may make it more difficult to fall asleep at night. If you’re able to nap without struggling to fall asleep at night then go for it. If napping is causing you to stay awake at night, try cutting them out.
Limit or eliminate alcohol. Contrary to popular belief, alcohol is not a sleep aid. Although it may help induce sleep, it is one of the most powerful suppressors of REM sleep which is critical to achieving high-quality shut-eye.
Future articles will dive much deeper into sleep and its four sub-levers. Next week we’ll begin to understand the four diseases that kill an overwhelming majority (~80%) of the population within industrialized nations. Stay tuned.
And, as always, please give me feedback on Twitter or by hitting reply to this email.
Much love,
Jack
Deep Dive: Sleep
Resources if you’re interested in doing a deeper dive into the world of sleep.
