The Everly Brothers were not the first to croon about the power of dreams, but they did pretty much corner the market for a while.
There’s a new kid in town – Matthew Walker – and Matt Osborne returns to Bacon today for a terrific discussion of his new book, Why We Sleep: Unlocking the Power of Sleep and Dreams.
I love to sleep.
Instead of chasing obsessions and anxieties as I do during my waking hours, when I sleep I can stand down and let my brain do its own thing for a while. Sleep seems to be the only time that I get completely out of my own way. Unfortunately, I don’t get as much of it as I would like.
I can fall asleep anywhere. I am the Theodor Seuss Geisel of falling asleep – on a train, in a chair, in a plane, anywhere.
The problem is staying asleep. Nearly every night there is a spouse, or a college student home on break, or a teenager, or a dog, or a bladder that wakes me up, and then my conscious mind resumes control until it finally gives out again.
I recently got a better picture of these nightly waking episodes. My wife won a Fitbit, which she didn’t need because she uses a Garmin, so I decided a few months ago to start wearing it at night to measure my sleep quality. The Fitbit revealed, on average, around thirty minutes to one hour of wakefulness each night, resulting in a net (again, on average) of around six and one-half hours of sleep per night.
I had little doubt that a sleep total of 6:30 was not ideal, but I wondered if it nevertheless was sufficient. What is it my brain and body need to do at night, and is 6:30 enough time in which to do it? If not, what am I losing? Is the loss critical? If it is critical, what can I do to get more sleep? How can I better my chances of increasing that 6:30 to, say, 7:30 or more?
Fortuitously, I happened across an interview with Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, which prompted me to pick up his new book, Why We Sleep: Unlocking the Power of Sleep and Dreams.
The Why of the title encompasses two subjects that Walker explores in depth. First, why do we fall asleep – i.e., what is it that occurs in our brain that makes us crash out? Second, why do we need to sleep – i.e., what are the effects of sleep on the human physical, mental, and emotional condition?
If you feel old and tired like me, you will want to read Professor Walker’s book for yourself, but I will hit a few highlights below to give you a sense of what is involved, and what is at stake, with sleep.
It may be that the best thing we can do to be kind to ourselves in this new year is to do nothing at all – just set aside whatever it is we have going on after dark, and go to bed.
“Come On, Get Rhythm”
Professor Walker lays the groundwork for his exploration of sleep science by explaining how it is that we fall asleep in the first place.
All human beings have a 24-hour pattern of wakefulness and sleep, known as the sleep rhythm, or circadian rhythm. The particular nature of this rhythm (the respective timings of the wakefulness peak and the sleepiness trough) will vary from person to person. Hence, some persons are “night owls,” while others are “morning larks.”
Driving this sleep process are melatonin and adenosine. The hormone melatonin begins to rise after sunset, and while it does not itself generate sleep, it signals the sleep-generating regions of the brain to begin the sleep process. In other words, melatonin starts the countdown to sleep launch. The chemical adenosine begins to build upon a person’s awakening, and accumulates during the day, thereby creating “sleep pressure.” The longer a person remains awake, the more adenosine that accumulates, and thus the greater the sleep pressure. At some point, the pressure is too great, and the person simply cannot keep his or her eyes open any longer. After eight hours of sleep, the average adult purges the accumulated adenosine, and the accretion process begins anew upon awakening.
In addition to this rhythm of waking and sleep, there also is a rhythm to the state of sleep itself – a rhythm within the rhythm. During each period of extended sleep, humans cycle through stages of non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep. This is an alternating pattern of NREM and REM sleep that occurs every ninety minutes. During the early part of the sleep period, most of each ninety-minute cycle is spent in NREM sleep. Toward the end of the sleep period, REM sleep occupies a greater portion of each cycle. As a result of this backloading of REM sleep, if a person wakes up too early (before the end of the full eight-hour adenosine purge), he or she may lose only 25 percent of total sleep time, but that translates into 60 to 90 percent of lost REM sleep time (with REM sleep being the period in which the brain fine tunes itself).
All of this (the circadian rhythm and the nature of the sleep cycles) varies with age. Teenagers, for example, most often are biologically programmed to be night owls, and they obtain more deep NREM sleep during their sleep cycles. As a person enters his or her forties, he or she begins to enjoy less deep NREM sleep, and has more frequent periods of wakefulness during the night. So, in the teenage home, everyone is tired – the teenager, because she is a night owl and the school system forces her to rise too early, and her mother, because Mom is getting a poorer quality of sleep.
So, when we (teenagers, or their parents, or those others of us who cannot or choose not to sleep for a full adenosine purge period) miss sleep, what are we losing?
“No Sleep till Brooklyn”
When we lose sleep, explains Walker, we lose “that most powerful elixir of wellness and vitality,” for it is sleep that
– “enriches . . . our ability to learn, memorize, and make logical decisions,”
– “recalibrates our emotional brain circuits,”
– provides “a consoling neurochemical bath that mollifies painful memories and a virtual reality space in which the brain melds past and present knowledge, inspiring creativity,”
– “restocks the armory of our immune system,”
– “reforms the body’s metabolic state by fine-tuning the balance of insulin and circulating glucose,”
– “regulates our appetite,”
– “maintains a flourishing microbiome within [our] gut,” and
– “lower[s] blood pressure while keeping our hearts in fine condition.”
To prove his point, Walker spends several chapters reviewing studies (it is more interesting than it sounds) that demonstrate the benefits of sleep for learning and creativity, motor skills and athletic performance, concentration and productivity, emotional equanimity and psychiatric health, cardiovascular health and blood pressure, metabolism, gut flora, and the immune system.
I will not recount the study details here, but from the evidence Walker marshals, one comes away from his book believing, as he does, that “sleep is the single most effective thing we can do to reset our brain and body health each day.”
“Send Me the Pillow that You Dream On”
So, how much sleep do we need, and how can we get more of it?
Walker agrees with the National Sleep Foundation and the Centers for Disease Control and Prevention, which recommend a sleep opportunity (i.e., time in bed) of seven to nine hours per night. This window allows for periods of nighttime wakefulness while still permitting enough time for sleep “to accomplish all that sleep does.”
Walker defines a “chronically sleep restricted” person as one who is “getting less than seven hours of sleep a night on a routine basis,” and warns that going ten days with only six hours of sleep per night renders a person “as impaired in performance as going without sleep for twenty-four hours straight.” Unfortunately, even three full nights of subsequent recovery sleep are insufficient to restore such a person to full efficiency. And it is not just academic, occupational, and athletic performance that suffer — a lack of sleep also affects our psychological health, our physical health, and our overall lifespan.
Walker offers three indications that you are not getting enough sleep: (1) If you did not set an alarm, you would sleep past the time at which you need to awaken. (2) After awakening in the morning at your usual time and starting your day, you easily could fall back asleep at 10:00 or 11:00 AM. (3) If you were to forego morning caffeine, you would have trouble functioning optimally before noon. (Don’t worry so much about the mid-afternoon alertness dip, or what Barney Fife would call the afternoon “sinking spell.” According to Walker, this “genetically hardwired dip” is common to all human beings.)
If one or more of these indicators is/are true for you, Walker suggests the following:
– Go to bed. As noted above, provide yourself with a sleep opportunity window of seven to nine hours.
– Get on a schedule. Do your best to go to bed and get up at the same time every day, even on weekends and holidays. According to Walker, this “is perhaps the single most effective way of helping improve your sleep.”
– Avoid vigorous exercise late in the day. Exercise raises core body temperature, which can forestall sleep (see “Keep it cool,” below), so try not to exercise within two to three hours before going to bed.
– Avoid caffeine late in the day. Even though the effects of caffeine peak around thirty minutes after ingestion, it persists in your system for several hours.
– Forego alcohol and sleeping pills. These are sedatives, meaning that while they will take you out of wakefulness, they will not lead to natural sleep with its accompanying panoply of benefits.
– Avoid large meals and too many fluids right before bed. Too much food may cause digestive discomfort, and too much liquid may result in a full bladder.
– If possible, adjust the time you take medications that may interfere with sleep. This, of course, is the prescribing doctor’s call.
– Avoid naps late in the day. While naps can be beneficial, Walker recommends against napping after 3:00 PM.
– Engage in a relaxing activity before bed. Allow some time before bed for the mind to ramp down.
– Keep it dark. Maintain a dark sleeping area. Avoid artificial light in the evening, especially blue LED light of the sort emitted from laptop, tablet, and cellphone screens.
– Keep it cool. Maintain a room temperature of around 65 degrees in your sleeping area. Core body temperature must drop by a few degrees in order for the brain to initiate sleep. A related strategy is to take a hot bath shortly before you plan to go to sleep. When you get out of the bath, your core body temperature will drop.
– Do not lie awake in bed for an extended period. If you are awake for more than twenty minutes, get up and engage in a relaxing activity (for example, reading a book, but not on a tablet reader) until you feel sleepiness coming on.
Of course, there are sleep disorders such as somnambulism, insomnia, and narcolepsy that make this easier listed than done for many people. Indeed, Walker notes that chronic insomnia is “disarmingly common.” While these disorders require the intervention of sleep specialists, Walker does provide a helpful primer on them. So, if you believe you have one of these disorders, Walker’s book still may be of interest to you. (Indeed, Walker’s book covers a great deal of ground. Other issues he discusses that I have not mentioned here include jet lag, shift work, the nature of sleep across the human lifespan, napping, Alzheimer’s disease, autism spectrum disorder, and post-traumatic stress disorder.)
“Golden Slumbers Fill Your Eyes, Smiles Await You When You Rise”
As much as I love to sleep, I cannot say that I consistently give myself the best chance to do it. Often there is an extended commute to crawl through, a high school ball game to attend, or an errand to run that encroaches into the time between work and bed. Sometimes I am taking advantage of the late quiet time to engage in a laudable pursuit – completing a workout, texting my father, or knocking out another chapter in a book. Admittedly, though, what often is keeping me up is another swipe through Instagram (I love seeing those old Blue Note album covers posted), or another Thin Lizzy video on Youtube (but perhaps Thin Lizzy videos go in the laudable pursuit category?), or checking a late score (who doesn’t want to go to bed exulting in the knowledge that Duke, the Yankees, the Carolina Panthers, or some similarly evil enterprise has dropped a game?).
Whatever the reason I am staying up, Walker has convinced me I need to shut it down earlier and extend my sleep opportunity window. This body and brain could use some natural elixir. So, “please don’t wake me, no don’t shake me, leave me where I am, I’m only sleeping.”
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Top image copyright here.