Why We Sleep

"Scientists have discovered a revolutionary new treatment that makes you live longer. It enhances your memory and makes you more creative. It makes you look more attractive. It keeps you slim and lowers food cravings. It protects you from cancer and dementia. It wards off colds and the flu. It lowers your risk of heart attacks and stroke, not to mention diabetes. You'll even feel happier, less depressed, and less anxious."

If this were a real advertisement, would you be interested? Because I most definitely would, and I am confident many would be willing to pay large amounts for it. Yet we have access to the elixir that provides all these benefits on a daily basis and for free but we are unappreciative and often disregard it as laziness. Evidence supporting the cornucopia of benefits brought about by sleep has been documented in more than 17,000 well-scrutinized reports and yet the general public remains unaware of this.

I, for one, spent most of my life thinking sleep was kind of a waste of time. In the fast-paced, competitive world we live in, I used to think sleep took valuable time away from me - time I could spend doing something "better" or "more productive". I consistently slept less than 8 hours even when I had the time to sleep more and never felt the need to change my ways until I encountered Matthew Walker's Why We Sleep.

Walker is a neuroscientist and sleep researcher whose compelling evidence on the importance of sleeping quite literally scared me into reconsidering my sleep habits. Walker does a superb job at taking readers through the inner workings of sleep, the myriad boons we can obtain from just a full night of sleep, the risks and dangers of our sleep-deprived society, and a number of other sleep-related topics.

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The Benefits

Sleep is beneficial for our entire bodies: for our organs, for our cognitive abilities, for our psychological and mental health, for our creativity, for our immune system, for our metabolism, for our appetite, for our cardiovascular system, and even for our physical appearance.

• There does not seem to be a major organ within the body that isn't optimally enhanced by sleep.

• Sleep increases our ability to learn, memorize and make logical decisions and choices.

• It helps our psychological health, making us more emotionally stable and less prone to "snapping" under stress or pressure.

• Evidence shows sleeping less than 6 or 7 hours a night demolishes our immune system.

• Sleep also keeps our metabolism in balance, regulating appetite, helping control body weight, and maintaining a flourishing microbiome in our gut. When we are sleep deprived, our blood sugar levels get disrupted and we tend to eat more and make unhealthier food choices.

• Sleep is fundamental for the fitness of our cardiovascular system, lowering blood pressure while keeping our hearts in fine condition. Not sleeping enough increases the likelihood of cardiovascular disease, stroke and congestive heart failure.

• Lack of sleep has been shown to be correlated to heart disease, obesity, dementia, diabetes and cancer.

In general, the shorter you sleep, the shorter your life span. Sleep seems to be the ultimate elixir, resetting our brain and body each night and making us be healthier, feel happier, and look better.

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The Research

Why We Sleep offers compelling evidence and research on the many benefits of sleep. I picked two of the experiments that resonated the most with me - one very similar to something I have empirically experienced and one I found so alarming I was finally convinced my sleep habits needed to change.

1. Sleep and Learning

On multiple occasions, I have stayed up late working on a project and ended up stuck. Sometimes when programming, I keep on getting errors and can't figure out how to solve them. Or I get the wrong answer over and over and can't come up with a solution. Eventually, I give up and go to bed. And then the next morning I go back to my project and the very difficult problem I simply couldn't figure out the previous night now seems to have an obvious solution. Most of the times it works so well and feels so easy I wonder how on earth could I not solve it before.

The experiment conducted by Walker was specifically about motor learning but the results immediately reminded of my own (non-motor) learning experiences. In the study, participants were asked to learn a number sequence on a keyboard (such as 4-1-3-2-4) as quickly and accurately as possible. They practiced for a total of 12 minutes and were asked to return 12 hours later to be re-tested. Those who were first tested in the morning returned in the evening and showed no improvement between sessions. However, the ones tested in the evening, whose second session was the following morning (after getting a full night's sleep), had a jump in both performance (20%) and accuracy (35%). What's more, the first group was also tested the following morning, and they too showed improvement after sleeping in between sessions.

It seems, like Walker suggests, that it isn't "practice makes perfect", but instead, "practice, with sleep, makes perfect."

2. Sleep and Concentration

David Dinges, a sleep researcher and professor at the University of Pennsylvania, devised a simple experiment to study the effects of sleep on concentration. Participants were split into four groups and asked to press a button in response to a light appearing on a button box or computer screen (the light appeared in an unpredictable manner). Both their responses and reaction times were measured. Unsurprisingly, those with less sleep did worse, but how much worse?

The unlucky group A had the most disastrous results: after just one night of no sleep, participants' lapses in concentration increased by 400%. Moreover, the results did not seem to flatten out, and performance just kept on increasing at a ballistic rate as more sleepless nights piled up.

Even more concerning is the fact that after 6 days of sleeping 4 hours, group B matched the level of impairment suffered by group A after the first sleepless night. Yet even more alarmingly, those sleeping 6 hours per night, which many of us do on a regular basis, also reached a 400% increase in impairment - it just took a little longer (11 days). What's more, participants sometimes showed no conscious or motor response whatsoever (this is known as a microsleep and can last from a fraction of a second to several full seconds). On the contrary, those sleeping 8 hours maintained a near perfect performance across the two weeks the experiment lasted.

You would think such a nosedive in concentration and response times would alert participants of their increasing impairment. However, the majority consistently underestimated just how bad their performance had become. It seems that after chronic sleep deprivation, individuals acclimate to their impaired performance, lower alertness, and reduced energy levels.

"This [impaired state] becomes the new baseline. Individuals fail to recognize how their sleep deficiency has come to compromise their mental aptitude and physical vitality, and never make a link between the two."

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Concerning, isn't it? And this is just the tip of the iceberg. Why We Sleep is filled with scientific and anecdotical evidence on just how tremendously important sleep is for us. The most worrying part, however, is how unaware we are of it, and how our culture perpetuates the "sleep is laziness" stereotype. I recently browsed a "self-guide" book that explicitly said something like "sleep is for the weak" and you can "will yourself" into sleeping just a few hours per night, without offering even the tiniest piece of evidence. It is almost impossible (not to mention incredibly dangerous and harmful to our bodies and health) for us to "will ourselves" into fighting one of our most basic needs, one that has been ingrained by millions of years of evolution.

We should aim to get a full night's sleep every time we can (which, in an ideal world, should be always, but has the world ever been ideal?). And even when we can't, we would gain so much just from making sleep a priority as opposed to putting it at the bottom of our list, the way I used to do and most of my friends and family still do. Sleep really seems to be the ultimate elixir of health, longevity, and well-being (not to mention it is free and feels good) and our society (and economy and productivity levels and everything else we seem to prioritize over sleep) would benefit from recognizing it.