Memory techniques to become superhuman! Productivity tools do more in less time! The ultimate workout to finally get in shape!
We’ve all seen these headlines before. Hell, I’ve even written some of them. The concept is simple enough — do this little thing and X will improve dramatically.
The trouble with these promises is that they’re asking you to build on an incomplete foundation. It’s like working on the roof of a new house before laying a single brick.
It’s ironic because there is a simple way to improve nearly every facet of our lives — and we already do it daily. The problem is that it’s misunderstood, unexciting, and time intensive (not the usual ingredients for an eye-catching headline). These perceived downsides prevent us from treating it like a true foundational aspect of our lives. So it’s pushed aside for activities with seemingly higher returns on investment.
That overlooked foundation is sleep, the most important contributor to our health, mental and physical performance, and overall well-being.
My eyes were opened to the far-reaching effects of sleep by Matthew Walker, pHD — neuroscience professor at UC Berkeley and sleep expert — during his epic interview on Joe Rogan’s podcast. His book, Why We Sleep, dives deeper into the powerful impact that sleep (or lack thereof) has on our lives.
I’ve summarized the power of sleep into three principles :
- Sleep improves almost every facet of human performance
- Conversely, not enough sleep will significantly hinder our capabilities
- Virtually all of us need 7-9 hours of sleep per night
Let’s explore each of these further.
💤 Principle 1: Sleep improves almost every facet of human performance
“Based on a rich, new scientific understanding of sleep, we no longer have to ask what sleep is good for. Instead, we are now forced to wonder whether there are any biological functions that do not benefit by a good night’s sleep. So far, the results of thousands of studies insist that no, there aren’t.”Walker, Why We Sleep, page 8
This is the main thesis of Why We Sleep and it’s beautifully simple — sleep improves every function in the human body.
Such as memory:
“…following a night of sleep you regain access to memories that you could not retrieve before sleep. Like a computer hard drive where some files have become corrupted and inaccessible, sleep offers a recovery service at night….The “ah yes, now I remember” sensation that you may have experienced after a good night of sleep.”Walker, Why We Sleep, 116
Or working on a difficult problem:
“Surprisingly, your brain can also work on a problem even while you are sleeping and are not aware of anything. But it does this only if you concentrate on trying to solve the problem before falling asleep. In the morning, as often as not, a fresh insight will pop to mind that can help you solve the problem. The intense effort before a vacation or falling asleep is important for priming your brain; otherwise it will work on some other problem.”Oakley, A Mind for Numbers, 5
You may have experienced this first hand while studying a language, learning a new skill, or deliberating a tough situation at work. Before bed we feel stuck and unable to chip away at the intricacies of the problem at hand. But by morning we’ve somehow magically made progress. As Walker explains, “Practice does not make perfect. It is practice, followed by a night of sleep, that leads to perfection” (126).
💤 Principle 2: Conversely, not enough sleep will significantly hinder our capabilities
When we don’t get enough sleep, the benefits noted above are unrealized and our performance noticeably suffers. Unfortunately, human performance doesn’t simply plateau during a sleep shortage — it takes a serious nosedive.
“Obtain anything less than eight hours of sleep a night, and especially less than six hours a night, and the following happens: time to physical exhaustion drops by 10 to 30 percent, and aerobic output is significantly reduced. Add to this marked impairments in cardiovascular, metabolic, and respiratory capabilities that hamper an underslept body, including faster rates of lactic acid buildup, reductions in blood oxygen saturation, and converse increases in blood carbon dioxide…”Walker, Why We Sleep, 129
The negative consequences of sleep loss might be most noticeable while behind the wheel of a car. It’s an environment that requires constant attention and the negative outcomes (crashes) are quantifiable.
“Operating on less than five hours of sleep, your risk of a car crash increases threefold. Get behind the wheel of a car when having slept just four hours or less the night before and you are 11.5 times more likely to be involved in a car accident. Staying awake for nineteen hours (e.g. waking up at 8 AM and driving home at 3 AM) causes cognitive impairment equal to being legally drunk.”Walker, Why We Sleep, 138
To put this in perspective, “vehicular accidents caused by drowsy driving exceed those caused by alcohol and drugs combined” (Walker 5).
Think back to the last time you pulled an all-nighter. Maybe it was cramming before a college final or a push before a crucial work project. Mine was on a sleepless overnight flight with my giant legs crammed against the seat in front of me. Now think about how you felt the day after staying up all night. For me, dazed, groggy, and cranky are adjectives that come to mind. Even if it’s been several years since your last official all-nighter, the side effects are easily reproduced.
“Most worrying from a societal perspective were the individuals in the group who obtained six hours of sleep a night—something that may sound familiar to many of you. Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for twenty-four hours straight.”Walker, Why We Sleep, 136
💤 Principle 3: Virtually all of us need 7-9 hours of sleep per night.
We all know a self-proclaimed superhero who claims they’re able to “get by on just 5 or 6 hours a night”. The assertion, while boastful, feels plausible. We’re all unique and it only makes sense that some people need less sleep than others. Scientists have even discovered a gene that controls the ability to fully function on minimal sleep.
“We have, however, discovered a very rare collection of individuals who appear to be able to survive on six hours of sleep, and show minimal impairment—a sleepless elite, as it were. Give them hours and hours of sleep opportunity in the laboratory, with no alarms or wake-up calls, and still they naturally sleep this short amount and no more. Part of the explanation appears to lie in their genetics, specifically a sub-variant of a gene called BHLHE41.”Walker, Why We Sleep, 145
Finally, some reassuring news! I thought so too, until Dr. Walker revealed the frequency of this gene.
“Having learned this, I imagine that some readers now believe that they are one of these individuals. That is very, very unlikely. The gene is remarkably rare, with but a soupçon [a very small quantity] of individuals in the world estimated to carry this anomaly. To impress this fact further, I quote one of my research colleagues, Dr. Thomas Roth at the Henry Ford Hospital in Detroit, who once said, “The number of people who can survive on five hours of sleep or less without any impairment, expressed as a percent of the population, and rounded to a whole number, is zero.”Walker, Why We Sleep, 145
To make matters worse, we’re not very good at recognizing the issues that arise when we’re sleep deprived. Everything seems OK but, in actuality, our performance is seriously undermined.
“When participants were asked about their subjective sense of how impaired they were, they consistently underestimated their degree of performance disability. It was a miserable predictor of how bad their performance actually, objectively was. It is the equivalent of someone at a bar who has had far too many drinks picking up his car keys and confidently telling you, ‘I’m fine to drive home.'”Walker, Why We Sleep, 137
How much sleep is actually “enough’? The rough answer: Between 7 – 9 hours per night. Outside of a formal sleep assessment, there’s a simple method to figure out if you need more sleep:
“If you didn’t set an alarm clock, would you sleep past that time? If so, you need more than you are giving yourself. “Walker, Why We Sleep, 36
Anyone else ready for bed?
During my research for this article, I stumbled across several Random Yet Interesting Sleep Facts:
💤 Our bodies adjust slowly to jet lag. “For every day you are in a different time zone, your suprachiasmatic nucleus (the region of the brain responsible for regulating our circadian rhythm) can only readjust by about one hour,” notes Walker (25). This means it takes about three days to truly adjust after a cross-country flight between NYC and LA, since there’s a three hour time difference between the two cities.
💤 Unihemispheric sleep “is sleep where one half of the brain rests while the other half remains alert.” It’s found in certain species of birds, dolphins, and whales and allows these animals to rest while in areas of high risk or migratory flights. This also allows some birds to literally sleep with “one eye open” — with a closed eye opposite the brain hemisphere that’s asleep and an open eye opposite the hemisphere that’s awake.
💤 There are theories under investigation that hypothesize humans also exhibit a “very mild version of unihemispheric sleep”. This could explain why we sleep so poorly in the first night in a new place (e.g. a hotel, the guest room at your Aunt’s house). “One half of the brain sleeps a little lighter than the other, as if it’s standing guard with just a tad more vigilance due to the potentially less safe context that the conscious brain has registered while awake” (Walker 66). Wild!
💤 Avoid the mid afternoon time slot, usually between 2 – 4 pm, for critical work meetings. To blame is our post-prandial alertness dip, which is a state of drowsiness due to the 1 – 2 punch of post-meal digestion and our bodies’ natural rhythm yearning for a siesta (Walker 69).
💤 The “power nap” was founded by scientists but named by marketers. In a 1990 NASA sponsored study, researchers discovered pilots on long-haul flights suffered from degraded performance due to lack of sleep. They recommended in-flight “prophylactic naps” to combat the loss in alertness. However, the FAA “believed the term ‘prophylactic’ was ripe for many a snide joke among pilots” and instead suggested “power napping” because it sounded better (Walker 144).
Walker, Matthew. “Why We Sleep. Unlocking the Power of Sleep and Dreams“
Oakley, Barbara. “A Mind For Numbers: How to Excel at Math and Science“