Sleep is The Black Box of Wellness. Let’s Open It.
Why we ignore sleep, how it hurts us, and how to get better at it.
Sleep is the black box of wellness, but it shouldn’t be that way. We know what time we go to bed. We know how we feel when we wake up, but what’s really going on in there?
As it turns out, quite a bit. What’s clear from the research is that sleep is one of the most powerful, natural levers we can pull to impact nearly everything we do. Thankfully, while we were busy chasing diet and fitness trends over the last couple of decades, sleep scientists were hard at work unraveling the mysteries of sleep. Recently, some of the top sleep scientists in the world translated years of their research into separate books, and their collective message is empowering. They want to hand us the keys that open the black box so we can radically improve our sleep.
We’re Sleep Ignorant
We know sleep is important, but we don’t take it seriously. Case in point, the average American sleep time has gone from about 8 hours per night to just under 7 hours since 1942, which is a big leap from getting 9 hours back in 1910. According to the National Sleep Foundation, 21% adults get less than six hours on most nights. And a full 69% say they get less sleep than they need to function at their best. So why do we give up sleep so easily?
The obvious reason is modern life. Replete with artificial lighting, climate-controlled buildings and other technical trappings, it draws us away from our true nature. And culprit number one is the mass scale adoption of light bulbs. Their adoption created a massive uncoupling of society from the natural rhythms of the sun, which we need so desperately to regulate our circadian biology.
Another driver of sleep ignorance is being too comfy. The advent of climate-controlled housing and workspaces has mismatched our environment with our core body temperature needs to initiate and maintain proper sleep.
More recently, our around-the-clock and often pernicious use of screens is also causing us to ignore sleep signals. Have you ever noticed how you can’t reach the end of scrolling through your Netflix cue or Instagram feed? Or how about that habit of checking work email one more time before you go to bed? These habits are tough to break for anyone but worth the effort.
Collectively, the changes in how we interact with light and temperature have driven a wedge between nature’s powerful sleep cues and our innate ability to be good at sawing logs.
A different angle on this issue is that sleep is mysterious. It’s a black box of sorts. Think about it, sleep happens while we’re unconscious and as a result, we pay it little reverence. Instead, daytime activities that command our full attention, like diet and exercise, steal the health and fitness limelight. When was the last time you saw someone post a photo of themselves sleeping on Instagram? It’s just not post worthy. When we exercise, we sweat, our heart rate increases, we feel our muscles burn, our breathing becomes labored. We flex and post it. When we eat, our sensory system lights up like a Christmas tree, our bellies expand, and we feel it. But first, we take a food selfie. Yet, when we sleep, it doesn’t seem like anything is actually happening, but this couldn’t be further from the truth. While we’re asleep, a beautiful biological symphony is taking place and ignoring it isn’t bliss. In fact, it’s quite the opposite.
The High Cost of Short Sleep
It’s pretty obvious that pulling an all-nighter makes you feel terrible and takes a couple days to recover. However, what blew my mind looking into sleep research was just how damaging it can be to shave off an hour or so of sleep on a regular basis. Sleep scientists call this “short sleep” and it can wreak havoc on the body.
Let’s take a look at sleep’s relationship to obesity, one of our greatest public health nightmares. Dr. Matthew Walker, author of Why We Sleep: Unlocking the Power of Sleep and Dreams, explains in his book a series of experiments carried out at the University of Chicago by Dr. Eve Van Cauter. She studied the impacts of short sleep on hormones and how much we eat.
A key finding was that people who got only 4 to 5 hours of sleep per night had increased levels of ghrelin and decreased levels of leptin compared to people who got up to 8 and a half hours. Ghrelin is the hormone that signals “I’m hungry, eat some food,” and leptin is the hormone that helps us say “I’ve had enough.” To put it simply, undercutting sleep means that we eat more and more of less satisfying and less nutritious food.
In an additional study, Van Cauter found that short sleepers ate an extra 300 calories per day. That may not sound like much but stretch it out over a year and it could amount to an extra 10 to 15 pounds around the waistline. But it gets worse. When short sleepers were offered a full buffet of both healthy and unhealthy foods, not only did they eat even more than 300 extra calories, they increased their preference for the unhealthy food options. When we skip sleep, we invite the extra pounds.
How about sleep as it relates to cancer? Dr. Walker describes another study where only one night of four hours of sleep decreased natural killer cell activity in healthy young men by 70 percent. That’s crazy when you consider that natural killer cells are like our own personal set of snipers that pick off cancer cells.
Brain fog is a term used a lot these days. And it’s a scary one because when we think brain fog, we think Alzheimer’s. And when we think Alzheimer’s, we think it strikes randomly, but that’s not exactly true. Evidence continues to show that a number of lifestyle factors play a role in Alzheimer’s, and sleep is no exception. One of the characteristics of Alzheimer’s is a buildup of a protein called beta-amyloid in the brain. And guess what’s good at getting rid of beta-amyloid build up? You guessed it, sleep. Specifically, during deep sleep, the brain drains away those pesky proteins associated with Alzheimer’s.
Beyond some of the bigger chronic diseases, sleep deprivation manifests in other insidious ways. When we’re sleep poor, we actually behave more at the extremes of our emotional spectrum. In a study done by Dr. Walker’s lab, they observed a 60 percent spike in emotional reactivity from the amygdala, often referred to as the lizard brain, because of its involvement in strong emotions, such as anger. According to Dr. Walker, “It was as though, without sleep, our brain reverts to a primitive pattern of uncontrolled reactivity.” This makes me wonder if there’s any connection between our lack of sleep and the vitriol that gets spewed on social media daily. What would the world be like if we all got just one more hour of sleep?
On a more positive note, there’s a lot within our control when it comes to getting better sleep. Especially if we take the time to understand what’s actually happening during shuteye.
We Have Clocks
If you want to sleep better, first you have to understand a little bit of circadian biology. Sleep is part of a much bigger pattern called circadian rhythm. This rhythm consists of the sleep and wake patterns that orient around a roughly 24-hour cycle, which is tightly linked with the movements of the sun.
Circadian rhythm is produced by a system of biological clocks located throughout the body through exposure to light and food. If you’re now envisioning a bunch of actual, physical clocks or watches placed throughout your body, that’s okay, but they are a little different. Our biological clocks are actually clusters of specialized cells that operate like a synchronized ecosystem to help run everything. The master clock, known as the suprachiasmatic nucleus (SCN), is buried deep within the hypothalamus in the brain. Although the SCN sounds like a nuclear weapon from a James Bond movie, it’s actually responsible for controlling the clocks throughout the body and a whole lot more than just sleep.
For example, let’s have a peek at how the SCN works with the clocks in the digestive system. Pretend you typically eat breakfast at nine a.m. The SCN works with the clocks in your digestive system to produce the enzymes needed to break down food around that same time every day. Ever notice how your stomach starts grumbling at the time you normally eat breakfast? That’s because your clocks help prime the digestive system to receive that food so you can get the most nutrition out of it. But what happens when you’re forced to eat early one morning, say breakfast at 6 a.m. instead of 9 a.m.? That food is likely to sit heavy in your stomach and leave you feeling sluggish. That one shift in timing created a sort of digestive jetlag. Your SCN didn’t get the memo about the early breakfast so your digestive system was asleep on the job. From this you can see not only how the SCN loves to run a tight ship but also how your clocks are personalized to your unique habits and patterns.
Our Clocks Have Patterns
We all have our own personal clock system, which is called a “chronotype.” It’s basically the natural preference for being a “morning person,” a “night person” or something in between. Knowing your chronotype can be a powerful tool for cracking the better sleep code and possibly more.
Though standardized methods of determining chronotype exist, Dr. Michael Breus, author of The Power of When, honed his own methodology through clinical practice. In his book, he lays out the four common types he’s observed over the years, all of which are named after mammals. He describes lions as the classic “morning people,” wolves, as the name suggests, are “night people,” bears occupy the middle and dolphins are very light sleepers (who often deal with insomnia).
Understanding your chronotype is like getting the circadian blueprint for building the perfect day. Because our clocks work in harmony with the environment and other biological systems, such as hormones, it enables predicting the best times of day for us to do all sorts of activities.
To that end, Dr. Breus lays out chronotype-specific plans to help customize our days and nights. For example, wouldn’t it be amazing to know the optimal times to eat, sleep or what time of day to get your best workout? Wouldn’t it be helpful to know the best times to make decisions, be creative, or even have an argument? Understanding your chronotype is a great start, but the impact comes from living in tune with it.
Recently, I turned a friend on to the chronotype approach and she called it a “total game changer!” I’m not surprised, as it’s always a fun moment when you figure yourself out a little better. In her case, she learned she was a wolf, so she now has proper justification for not being a morning person. And just as each person has their own unique pattern, each stage of sleep is unique as well.
Staging for Quality
To date, most sleep conversations revolve around total sleep time, which is only scratching the surface. The rapid adoption of wearable fitness trackers coupled with advancing sleep science is shifting the conversation to sleep quality. And to understand sleep quality is to understand sleep stages.
At night we move through a number of sleep cycles, each of which is made up of five different stages of sleep. Each cycle is broadly divided between non-rapid eye movement sleep (NREM), which has four stages, and rapid eye movement sleep (REM), which has one stage. Each sleep stage has its own biological signature and performs a unique role in the body.
Stages 1 and 2 are considered light NREM sleep and prepare us to go into deeper slumber. During NREM stages 3 and 4, or deep sleep, blood pressure drops, pulse rate slows and the brain waves go into a very slow and rhythmic pattern. In REM sleep, which is when we dream, the brain gets very active with short brain waves and heart rate increases.
Broadly speaking, during NREM sleep the brain moves short term memories into long term storage and performs a pruning of unwanted neural connections. This is similar to backing up a local hard drive from a laptop to the cloud for safe keeping at the end of the workday.
The REM stage is when the brain integrates all the new information received during the day. Specifically, it appears to integrate emotions, motivations, memories, and form new connections. It’s this integration work that helps with complex problem solving. It’s no wonder that REM is when the brain creates those strange and vivid stories we call dreams.
It may help to think about NREM as a director of photography uploading all the imagery from a day on a movie set, tagging it, organizing it and backing it up in preparation for editing. Then REM acts as the editor selecting scenes and mashing them together in a way that tells a complete story. And just like making a movie, once you have all the scenes uploaded into the editing system, the number of ways you can piece together a story are practically endless.
In rather Tarantino-esque fashion, our sleep cycles aren’t as sequential as you might imagine. Though it takes about 90 minutes to move through a full cycle of sleep, the amount of NREM and REM isn’t evenly balanced in each cycle. Earlier in the night, we get disproportionately more NREM sleep. In the latter half of the night our sleep cycles are more REM rich. So when we only get six and half hours of sleep, which might not seem like much, we’re actually lopping off a massive chunk of REM, which is again, is when the brain does the hard work of emotional restoration.
Another thing that messes with REM sleep is late night alcohol consumption. Alcohol also causes a pattern of mini wake ups through the night that we don’t even notice. However, it’s easy to notice not feeling awesome the next day.
Another common sleep troublemaker is our beloved caffeine, especially in late afternoons or evenings. I often hear people say they can drink coffee in the evening and still go right to sleep. That may be true, but what’s also true is that caffeine interferes with stage 4 NREM sleep, meaning that even though a person can fall asleep easily, they may be gambling on poor memory consolidation.
To ensure high quality sleep, we need to continuously string together all of the sleep stages and repeat that for about five cycles per night. Thankfully, there are some proven principles that can help us do exactly that.
Building a Sleep Foundation
Instead of providing a clickbait list of tips, the goal here is to understand the foundational principles of better sleep. From here, it will be up to you to channel your inner circadian animal and build the habits and hacks that work for you.
Consistency is Circadian Gold
Go to sleep at the same time every night. Wake up at the same time every day. Sounds easy, right? But it’s not easy at all, because…life. We all have things to do that cause less than ideal swings in our schedules. Sleep scientists call this misalignment of our social lives and circadian clocks “social jetlag,” which we all experience to some extent. Dr. Walker has this to say about consistency, “It is perhaps the single most effective way of helping improve your sleep…” As we discussed, our internal clocks love consistency and if we behave accordingly, then biology works in our favor. Though I find consistency to be the most challenging principle to apply, when I put together a three-day run of consistent sleep and wake times, my energy levels are off the charts as a reward.
Tune in to Temperature
Body temperature is the biological backdoor to better sleep. In order to initiate sleep, the core body temperature needs to drop around 1 to 3 degrees Fahrenheit. When this happens, we get a little kick of melatonin, which helps the body realize it’s time to prepare for sleep. Once you realize how many other lifestyle habits influence core body temperature, it’s easy to make adjustments for more sound slumber.
First, make your bedroom cooler. Around sixty-five degrees Fahrenheit seems to be the sweet spot for initiating good sleep. Dr. Satchin Panda, author of The Circadian Code who also runs the sleep lab at the Salk Institute, explains that when your skin cools, “…blood flows toward your skin to keep your skin warm. Since the blood is flowing away from the core of the body, the core body temperature can fall and you will fall asleep much easier.”
Another proven biohack is taking a hot shower or bath before bed. This may seem counterintuitive, but the hot water actually causes blood to flow to the surface away from the core, thereby dropping core body temperature. According to Dr. Walker, one study found a 10–15% increase in NREM sleep simply from a hot bath before bedtime.
Though many of us love to exercise after work, don’t push it too late into the evening. Exercise can keep your core running hot for hours afterwards, which is why sleep experts recommend finishing your workouts at least 2 to 3 hours prior to bedtime.
Late night eating is a major sleep disruptor. Dr. Panda has helped us understand much of what we know about eating and metabolism as it relates to sleep. His recommendation? “To have a good night’s sleep, we should have our last meal at least 2 to 4 hours before going to bed to ensure that the body is able to cool down.” That’s because when we eat, blood rushes to the core to carry out the work of digestion, which raises core body temperature.
Right Light, Right Time
When it comes to light and circadian rhythm, timing is everything. We experience light as a spectrum of colors and blue light often gets labeled as “junk light,” which isn’t exactly true.
Blue light is part of the naturally occurring sunlight spectrum and during the day, it helps us stay alert. In fact, to improve sleep it’s wise to rethink early day routines.
When we think about sleep, we often focus on our nighttime habits first. However, getting early morning sunlight exposure kicks off a series of reactions in the body that help to ensure we have enough melatonin production after sundown. If you don’t get enough early day sunlight, then you won’t have enough melatonin to signal bedtime at night. Sleep scientists recommend getting an hour of morning sunlight as a powerful way to anchor the circadian rhythm. However, be sure to keep that blue light exposure relegated to daytime because at night it’s not so friendly.
For example, when exposed to excessive blue light after sunset, instead of the brain saying “Get ready for sleep,” it says, “It’s noon in Hawaii so wake up!” This is where modern technology steps in as the common sources of junk light at night are LED lightbulbs, smartphones, laptops and tablets.
In his book, Dr. Walker describes a study in which researchers compared a couple hours of bedtime iPad reading to printed book reading and the results were eye opening. They found that melatonin was cut by 50 percent, it kicked in 3 hours later than it should, and participants took longer to fall asleep. What’s more, they lost REM sleep, felt sleepier the next morning and continued to experience a delay in melatonin rise for days afterwards. In other words, junk light before bed creates a kind of digital jetlag. The good news? All of this this is highly preventable.
The top tactic is to make your bedroom really dark. No, really dark. That’s not dark enough, go darker! Do an audit of your room to hunt down sneaky sources of light, such as tiny LEDs on appliances, cable boxes and alarm clocks. Either get them out of your room or cover them with a little piece of tape because it makes a difference. Both Dr. Panda and Dr. Walker point out in their books that even small amounts of dim light can upset melatonin production. If you can’t make your room truly dark, which is increasingly common due to light pollution, a simple hack that works is sleeping with an eye mask.
“In short, when it comes to managing light for better sleep — make your days brighter and your nights darker.”
Quiet the Mind
These days, it seems like nearly everyone is dealing with more stress and anxiety. Obviously, that doesn’t help with sleep. Below are a few easy and accessible ways to quiet the mind before bedtime.
Meditation can be a powerful way to unwind. It has been found to not only help improve sleep quality, but also lower blood pressure and ease anxiety. If the word “meditation” isn’t in your wheelhouse, then ditch the label and try this easy breathing practice. Simply sit quietly, draw a deep inhale up through the nose and down into the belly. Then do a long, audible exhale through pursed lips as if you’re blowing through a straw. Repeat this for a few minutes before you slip under the covers and drift off for the good stuff.
Yoga is another pre-bed ritual that can help ease us into sleep. Though many people think of yoga as just stretching or balancing, it can also be a powerful tool for relieving stress, which in turn can help us get more z’s. As a watch out, avoid the styles of yoga that build too much heat in the body, which will take your core temperature in the opposite direction you need for sleep. Instead, focus on slow, easy movements and practices cultivating deep breath.
A lesser known technique for reducing stress before bed is to write out your to-do list. With information overload so rampant these days, it’s easy to go to bed only to have the mind kick in and ruminate on everything that must be done tomorrow. That can cause cortisol to spike and suddenly we’re wide awake. A unique study found that writing a very specific to-do list for five minutes before bed actually helped participants fall asleep quicker. The lesson? Empty the mind, sleep better.
Nighty Night
Hopefully it’s now clear that sleep should not be a black box, and that it deserves its rightful place among the core pillars of wellness. We know missing out on it is devastating. On the flip side, the techniques to improve it are largely free, customizable and hold massive potential to improve wellbeing. The box is open. Time to crawl in and go to sleep.
