The Science and Practice of Effective Sleep

LifestyleMindset
Written By Simone Smerilli

DISCLAIMER: This article on sleep draws significantly from this 3-hour podcast episode from the Huberman Lab podcast featuring dr. Matthew Walker. Confirming evidence of the statements included in this essay are only cited sporadically. Hence, this essay is not a complete depiction of the current scientific evidence on sleep and should not be taken as such. Rather, you can think of it as a thought-provoking piece aimed at raising awareness on the relevance of sleep for athletes and non-athletes. The careful reader can deepen their understanding of the topic by listening to the podcast episode, consulting the sources cited at the end of this post, and diving into the currently available research on sleep.

If you are anything like me, you may have always (implicitly) believed that we can make up for the lack of sleep we expose ourselves to, say when we spend a long night out partying. That belief does not correspond to reality. The science and practice of sleep are nuanced and complex. I have been delving into the science and effective practice of sleep over the past few months. Recently, I listened to a comprehensive podcast episode between dr. Andrew Huberman and dr. Matthew Walker. Dr. Walker is one of the most renowned sleep experts of our time (or at least one of the most popular scientists who shone a light on the relevance of effective sleep for our well-being). I am no expert in this field. And through this post, I do not intend to pose myself as one. My intention here is to break down and analyze some essential best practices and concepts related to sleep, with a beginner's mind. My purpose is to spark interest in this topic, which I perceive incredibly important but far too overlooked in our existence.

What is sleep

Sleep is a functional mechanism rooted in human evolution. It is not merely the opposite of wakefulness. There is much more to sleep than resting. The primary purpose of sleep is utilitarian and engrained in human evolution. When we are awake, we will return to sleep at some point. Sleep seems to be a fragile and vulnerable state for human beings (being unconscious does not appear to be evolutionarily advantageous—the unconscious state of sleep makes humans and other animals vulnerable to the external environment). Yet, sleep has continued to evolve with us, unquestioned and always playing a pivotal role in our existence.

Sleep serves multiple functions. It is a single system used in multiple ways to optimize the functioning of our organism. Some of the most relevant functions of sleep discovered so far include memory consolidation, emotional regulation, fostering clear-mindedness, and alertness in our wakeful state (Worley, 2018). In the athletes population, sleep is an essential tool to optimize performance, minimize injury, foster appropriate resting. Overlooking the relevance of sleep for athletes in particular is an unwise mistake. We can "get sleep right" and optimize our lives for sleep. Doing so can result in increased life satisfaction and overall well-being.

What happens when we sleep

Broadly speaking, sleep can be broken down into two major phases: Non-REM and REM (rapid eye movement). More specifically, there are four sleep cycles identified in humans. Each cycle lasts approximately ninety minutes and occurs on average four to six times during the night (Patel, Reddy, Araujo, 2021). REM sleep is considered the most fundamental cycle for appropriate resting. On the other hand, deep sleep is part of the NREM cycle and takes place right before REM. So, while it is generally believed that deep sleep is crucial for restful nights, such a stage is not as important as REM sleep for optimal resting.

Just before REM, the brain sends a signal to our spinal cord, a signal of paralysis. Such a sign allows the mind to dream safely (without you taking action to the dream). Dreams happen during REM sleep, in the middle of which our eyes move horizontally very quickly. While the first part of our sleeping hours are mostly spent in deep sleep, as we approach light (the morning), the 90-minute cycles are principally composed of REM sleep.

How to get sleep right

The benefits of optimized sleep are significantly life-enhancing. Being well-rested can positively impact our relationships with the people and the world around us. Appropriate sleep can increase drastically athletic performance in athletes. It can decrease athletes' risk of injury and boost work capacity. Getting sleep right is a worthy pursuit. We can incorporate effective routines and protocols in our daily lives to maximize our ability to sleep and function properly. Dr. Huberman and Walker shared some actionable protocols we can implement to maximize sleep effectiveness. Below is a description of them.

  • Expose yourself to sunlight in the morning upon waking up for at least ten minutes. Even if it is cloudy or rainy, the sunlight is present and much stronger compared to indoor light from a lamp. Your eyes must be exposed to the light of the day. That's because our eyes determine "where" we are in the day and are pivotal in the regulation of our circadian rhythm.

  • Drink coffee (if you do) only after about ninety minutes from waking up and up to around eight hours before you go to sleep. Drinking coffee is fine from a health perspective based on our current understanding. Caffeine timing makes a difference. To understand why caffeine timing is fundamental for maximizing its effects, it is worth understanding how caffeine works in our bodies. Caffeine acts on specific brain receptors, "shutting down" a neuromodulator responsible for the onset of sleepiness: adenosine. Hence, caffeine acts as an adenosine receptor antagonist. I find this mechanism rather fascinating because it shows that caffeine does not directly boost our wakefulness (although that tends to be the effect we experience). Rather, caffeine temporarily blocks sleepiness ("knocking out" its receptors). Caffeine lasts about five-six hours in our body, although its duration varies on an individual basis (some people are more sensitive to caffeine than others). That explains why it is not recommended to drink coffee eight hours before sleep: caffeine will remain in the body, decreasing significantly the quality of our sleep (which is more important than quantity).

  • Reduce alcohol consumption to a minimum. Alcohol is often used as a sleep aid. The quality of our sleep suffers if we consume alcohol before going to sleep. Alcohol can help us lose consciousness faster, but it decreases the quality of our sleep and makes us wake up numerous times in the night. This cycle leads to a decrease in REM sleep, hence impacting our health and well-being. The same appears to be valid for substances such as Marijuana and CBD. They foster the loss of consciousness but generally diminish the quality of our sleep.

  • Ingest melatonin supplementation only if you cannot fall asleep. Melatonin is a hormone released in our body when dusk approaches (signaling to the body that "sleeping time is approaching"). Supplementing with melatonin does not increase the quality of sleep (i.e., REM). The only benefit one could draw from using melatonin is that it helps fall asleep faster.

  • Have a wind-down routine before sleep (don't expose yourself to light). Defining a clear wind-down routine before getting to sleep can be a powerful tool to enhance the quality of our sleep. We must not expose ourselves to bright light during the wind-down routine. If we fail to follow such advice, we may risk signaling to the body that it is still daytime. It is also pivotal we free up our minds before getting to sleep. Sleep rumination is detrimental to sleep quality. Due to yet-to-be-known reasons, thoughts tend to be catastrophized/magnified during the night. Regurgitating whatever is going on in our minds as part of a wind-down routine can be extremely beneficial when it comes to sleeping "better."

  • Remove clocks from your room (including phone). As dr. Huberman and Walker suggest, clocks are not useful during the night. This point is to some degree linked to the one above. Checking clocks if you wake up during the night does more harm than good. It may merely increase the already-present anxiety and cognitive distortions preventing us from staying asleep. There is an emotional aspect to sleep, and these last two protocols markedly underline this concept.

Life is Irregular. Stick to Your Circadian Rhythm

Even if we tried to maximize every single aspect of sleep, life happens. For the wide majority of individuals, optimizing sleep is not the only objective. Most of us have jobs, careers, a social life, hobbies, relationships. Life is irregular and that is ok. Sticking to our circadian rhythm seems to be a core recommendation in the domain of sleep. That means going to sleep and waking up at the same time every day. If we decide to get to sleep later than usual on some days (e.g., because of a party or night out), it is best practice for our own well-being that we wake up at the same time, as usual, the next day. Our circadian rhythm will adapt once we go back to our routine.

Naps are an additional useful tool we can take advantage of in the context of proper sleep. The ideal nap time is around 20 minutes, as dr. Walker points out during the conversation with dr. Huberman. Through naps, some sleepiness (adenosine) is decreased. The only caveat of naps is that they can be detrimental for people with insomnia. Those individuals may have even more trouble sleeping during the night if they take a nap during the day.

Getting sleep right is a worthy pursuit. It requires conscious effort to let things flow naturally around us, rather than being influenced by modern technologies and substances that may make our sleep unnaturally worse. Ultimately, the body knows it best. Wu-Wei, the Taoists would say.

RESOURCES

Simone Smerilli
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