[00:00:06.4] ANNOUNCER: Welcome to The Science of Success introducing your host, Matt Bodnar.
[0:00:11.8] MB: Welcome to the Science of Success; the number one evidence-based growth podcast on the internet with more than a million downloads and listeners in over a hundred countries.
In this episode, we discuss everything you ever wanted to know about sleep. We examine the findings from hundreds of studies across millions of people and pull out the major findings about how vitally important sleep is. Talk about the global sleep-loss epidemic.
The simplest and most effective evidence-based strategies for getting better sleep and much more with Dr. Matthew Walker. I’m going to give you three quick reasons why you should sign up and join our e-mail list today, by going to successpodcast.com and signing up right on the homepage. There is some amazing stuff that’s only available to our e-mail subscribers, so be sure to sign up.
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Next, you’re going to get a curated weekly e-mail from us every single Monday, called Mindset Monday; it’s short, simple, articles and stories that we found fascinating in the last week. Lastly, you’re going to get a chance to shape the show, vote on guests, change our intro music, submit your own questions to our upcoming guests and much more. You should sign up today. Go to successpodcast.com, join the e-mail list right on the homepage, or if you’re on the go, if you’re on your phone right now, just text the word “smarter”, that’s S-M-A-R-T-E-R to the number 44222.
In our previous episode, we went a bit off the beaten path, given the time of year when many are thinking reflecting and being a bit more spiritual, we wanted to offer a little bit of a different perspective. Our previous episode is not as science-based as some of our other interviews, but it provides a fascinating dialogue with a Buddhist monk who is the first Westerner ever ordained by the Dalai Lama. We discussed life, meditation, mindfulness and much more with our guest Robert Thurman. If you want an introspective look at mindfulness, listen to that episode.
Now for the show.
[0:02:21.7] MB: Today, we have another fascinating guest on the show, Dr. Matthew Walker. He’s a professor of neuroscience and psychology at UC Berkeley and a founder and the director of the Center for Human Sleep Science. He’s published over a 100 scientific studies and is the author of the book, Why We Sleep: Unlocking the power of Sleep and Dreams, which is currently the number one Amazon bestseller in the neuroscience category. He’s been featured on TV, radio, including CBS’s 60 Minutes, National Geographic and much more.
Matt, welcome to the Science of Success.
[0:02:53.7] MW: It’s a pleasure to be on Matt. Thank you for having me.
[0:02:56.2] MB: Well, we’re very excited to have you on here today. I’d love to begin the conversation and talk a little bit about – as I think you’ve called it the sleep deprivation epidemic, and what happens to us when we don’t get enough sleep.
[0:03:11.4] MW: You’re right. There is currently a global sleep-loss epidemic. This is sweeping developed nations. It’s been underway for probably about 60 or 70 years. We know from surveys back in the 1940s that the average American adult was sleeping 7.9 hours a night. Now we know that number is down to 6 hours and 31 minutes during the week for American adults.
Back in my home country, not much better. It’s 6 hours and 49 minutes on average people are sleeping. Japan seems to be the worse; 6 hours and 22 minutes. I just give you those numbers to reaffirm first this pernicious erosion of sleep that has happened over the past 70 or 80 years as truth. But also just to take a step back, I think we have to realize that it took mother nature 3.6 million years to put this necessity of 8 hours of sleep in place.
Then we have come along, and in the space of blink of an evolutionary eye; 60, 70 years we’ve locked off maybe 20%, 25% of that sleep amount. How could it not come with deleterious consequences? I think it’s been proudly confirmed that we are in a global sleep-loss state of deficiency, or an epidemic as the CDC and the World Health Organization have called it.
What are the consequences though? Because if it’s not doing us any harm, then why worry? If only that were true, there is demonstrable harm that is underway because of the sleep-loss epidemic. We can start at the big 30,000-foot level and make it a very simple statement based on epidemiological studies from millions of people. That is the shorter your sleep, the shorter your life. Short sleep predicts all-cause mortality.
I think that classical maxim that you may have heard. You can sleep when you’re dead. It’s always struck me as ironic, because if you adopt that mindset, we know from the evidence that you will be both dead sooner, and the quality of that now shorter life will be significantly worse.
If you dig down a little deeper you can say, “Well, if a lack of sleep kills you more quickly, then what is it that is killing you more quickly?” It seems to be just about everything. Every made disease that is killing us in the developed world has causal insignificant links to a lack of sleep. That list currently and tragically includes Alzheimer’s disease, cancer, cardiovascular disease, stroke, diabetes, as well as numerous mental health conditions; depression, bipolar disorder and most recently and sadly, suicide as well.
I think we’re really now starting to understand not just how deathly a lack of sleep is and the current weight of our sleep deprivation, and that elastic band of sleep deprivation can stretch only so far before it snaps. But with also understanding from hard science exactly why a lack of sleep produces such disease, sickness and ill-health within the brain and the body.
[0:06:31.1] MB: It’s amazing and it’s so important to think about why sleep is so vital. Yet, in today’s society it seems like there is more and more of a push to sleep less, work more, hustle more, do more. How do we combat that?
[0:06:49.5] MW: There is. I think currently, sleep has an image problem in society, because more often than not, we seem to stigmatize sleep and we suggest that people who are getting sufficient sleep and I actually choose my words quite carefully there. As being lazy, as being slothful, those who get maybe 7 or 8 hours of sleep a night.
People I think are – or some people, I should say. Not all, but some people are perhaps quite proud of the fact of how little sleep that they’re getting and where it almost as though it’s a badge of honor to be celebrated. It’s sad, because for all of the reasons that we’ve just discussed, it’s an ill-advised mentality to expose.
It’s also strange, because if we don’t always have that opinion. I don’t think any of us would look at an infant sleeping during the day and say, “Gosh, what a lazy baby.” We don’t do that, because we know that sleep at that time of life is absolutely non-negotiable. It’s fundamentally necessary. But if you look at the evidence somewhere between infancy and now even childhood, not only do we abandon this notion that sleep is necessary and important, but we give it this terrible stigma.
I think that attitude has to change, and there are many ways in which it has to change. I think part of the problem perhaps is that the science of sleep is actually not being adequately communicated to the public. I think it’s people like myself who are to blame. I’m a sleep scientist, a professional sleep scientist for 20 years now.
I can’t go around wagging the finger at people if people have not been educated by the science that the taxpayer dollars have funded. That was part of the motivation to write the book that I didn’t feel as though there was a book after that gave people a blueprint manifesto of all of the real hard science of sleep.
There are lots of books out there that you can buy about the quick fix, these are the 10 rules to better sleep, or – I got nothing against those types of books, but for me I felt it was important because my sense is that people don’t respond to rules. They respond to reasons rather than rules, and I wanted to give and write a book of reasons for why you should sleep, rather than rules for how to sleep.
[0:09:27.7] MB: I want to dig a little bit more specifically into some of the negative implications or maybe the flipside of why sleep is so important for certain activities. For somebody who – let’s contextualize this maybe within a framework broadly thinking about, if I want to get more work done people often say, “All right, I’m going to sleep less,” or, “I’m going to pull a all-nighter,” or, “I’m going to cut down on my sleep so I can be more productive,” how does that usually pan out? What does the science say about doing that?
[0:09:59.5] MW: It doesn’t pan out very well. In fact, the opposite is true; we now know that less sleep does not equal more productivity. There have been lots of laboratory and workplace with these, and they give us five clear truths. Firstly, underslept employees tend to take on less challenging work problems. In other words, they opt for the easy way out. Underslept employees actually produce fewer creative solutions to work problems that they’re facing.
They also actually exert less effort when working in groups, and we’ve done some of these work. They essentially slack off. It’s what we call social-loafing. They write the tale of others and try to claim their hard work is their own.
We also know very interestingly that underslept employees are more likely to lie, cheat and engage in deviant behaviors, such as falsifying a claims, receipts, etc., and it’s a scaling function; the less sleep that you have, the more likely you are to lie and be deviant.
What’s also interesting is that it scales the business hierarchy all the way up to the top. We know that the more or less sleep that a business leader has had, the more or less charismatic their employees will rate that business leader.
Even though the employees themselves know nothing about how much sleep that business leader has had. They can actually see it in the expression of the behavior of their leader. You can then actually scale that up from those that have low-level studies, all the way up to the high-level studies. There was a recent round report, an independent report that demonstrated that chronic exhaustion and fatigue due to a lack of sleep caused most first-world nations about 2% of their GDP. For the United States, that’s 411 billion dollars that we lose each year due to a lack of sleep.
If you can just think about that, if we solve the sleep deprivation problem in the US, we could almost double the budget for education and we could make huge in-roads into the problems that we have with healthcare. Or we could just flat out give people remarkably high tax rebates, simply by solving the sleep-loss epidemic.
I think in response to your question, it’s very clear that underslept individuals are not going to be successful. It’s a little bit like, if you think about your workforce and you’re forcing them to come into work every morning, early and leave very late, so no one is getting enough sleep, it strikes me a little bit like a spin class at a gym.
Everyone in the office looks like they’re working hard, but the scenery never changes, there’s never any forward progression in terms of momentum with productivity and creativity. I think we need to change our attitude in the workplace regarding sleep. The evidence is very clear there.
[0:13:04.3] MB: Especially around the creativity and the productivity aspect of that. It makes me think almost about the – an applied version of the 80-20 principle, where it’s not necessarily just more hours of work equals more output, but it’s really vital to have quality work, where you’re creative, where you’re bringing a fresh perspective and a well-rested mind. That’s when you really produce value. That’s the 20% that produces 80% of your results. All the busy work and the hustle and muscle, if you don’t get enough sleep you’re not going to be able to really be incredibly productive.
[0:13:44.3] MW: I think that that’s very true. Is there a way that we could actually break the classic [inaudible 0:13:50.0] 80-20 law that’s common throughout nature and it’s applied to human beings as well. By way of manipulating sleep could we actually force it to be that it’s 30% or 40% of your workforce that returns now 80% or 90% of the productivity by way of sufficient sleep.
It’s just coming down to the very fact that what is the recycle rate of a human being? I think people have failed in the workplace to actually face this question and ask it. It’s surprising, because people in the workplace are wonderfully astute at trying to squeeze every ounce of effectiveness and efficiency out of all of their systems, be it the budget, be it the tax, be it the hardware, be it the software.
I think we forget about the biological organism at the heart of most companies, the human beings themselves. We have to ask, “How long can an individual be awake before they decline and decline significantly in the productivity, efficiency and effectiveness?” We now know that that evidence, you need 8 hours of sleep, 16 hours – after 16 hours of wakefulness, the cognitive capacities and the physiological capacities of the body starts to decline dramatically in after 20 or 21 hours of being awake. You are as cognitively impaired as someone who would be legally drunk in terms of driving behind the wheel.
There really is a recycle refresh rate of a human being, and we know that and it declines dramatically once you get past that 16. What I’m suggesting there is not 16 hours of work. I’m suggesting that this 8, 9-hour work span, then people need that downtime and they need to get that 8 hours of sleep to reboot and refresh.
[0:15:45.3] MB: What’s actually happening during that recycling period?
[0:15:49.7] MW: Well, we know firstly that there are multiple different stages of sleep that we ebb and flow in and out of, throughout a full 8-hour phase. Those different stages of sleeping, the two principle types of sleep, I should note that probably most people are aware of, or what are called non-rapid eye movement sleep, or non-REM sleep, and rapid eye movement sleep or REM sleep, which is the stage principally from which we dream.
Non-REM sleep actually has several sub-stages to it, stages one through four, increasing in the depth of sleep. By the way, it always strikes me as funny that scientists are not a very creative bunch. We have these four stages of deep non-REM sleep, and all we could come up with was stages one through four. Let’s set that side for a second.
We know that all of those different stages of sleep perform different functions end up all necessary. To come back to your question though, exactly what is happening at night? Well, let’s take deep non-REM sleep for a start. The deepest stages of non-REM sleep. That stage of sleep is actually critical for essentially clearing out all of the metabolic toxins that have been building up in your brain.
Now that may sound a little bit hand-waving, but is actually very hard to get science from animal studies. When we are awake, we are essentially in a form of low-level brain damage. That’s what wakefulness is. We produce a variety of metabolic byproducts as a result of all of that waking brain cell combustion that we’re doing.
It is during sleep at night when we clear that away. What is clearing that away? Well, it turns out that we made a discovery, which is a sewage system in your brain. Now you have a sewage system in your body that you’re probably familiar with called the lymphatic system. But your brain also has one, it’s called the glymphatic system after the cells that produce it or compose the system called glial cells.
That sewage system within the brain, glymphatic system, is not always on, at least not in highest flow capacity. It’s only during sleep and particular deep sleep at night where that cleansing system of the sewage network actually kicks in to high gear. It increases by maybe 2 to 300% relative to when we’re awake.
Why is this important? Well, one of the metabolic toxins that the glymphatic system clears away as we sleep at night is a toxic protein called beta-amyloid. Beta-amyloid is one of the leading candidate causes of Alzheimer’s disease. This is why we know that people who are not getting sufficient sleep across their lifespan are at a far high risk probability of going on to develop Alzheimer’s disease. The less sleep that you have, the less clearing away of that toxic byproduct. That’s one way, general way that we know that the brain gets essentially a refresh.
We also know that different cognitive systems and networks within your brain undergo a restoration. For example, we know that learning in memory systems get overhauled. We take information that we recently learned and we transfer it from short to long-term memory during sleep, which is actually like hitting the save button on new memories, so it prevents you from forgetting by cementing and solidifying those memories into long-term story sites.
We also know that there is a clearing out of your short-term memory reservoir. It’s perhaps a little bit like shifting files from a USB stick, so that when you wake up the next day, you have this renewed capacities to start learning and acquiring new facts and information all over again. That’s a more specific way in which the brain actually gets an overhaul at night during sleep.
We also know that the emotional circuits of the brain are changed and modified by sleep. There are deep emotional brain sensors, very old evolutionary centers specifically a structure called the amygdala, which controls the vital flight response. That structure, the amygdala is normally regulated in us higher order primates, human beings specifically, by a part of the brain that sits just above your eyes called the prefrontal cortex, which acts a little bit like the CEO of the brain. It makes very high-level executive top-down control decisions.
When you had a good night of sleep, that part of your frontal lobe has been reconnected to your deep Neanderthal amygdala fight or flight center of the brain. It just regulates it. It’s a little bit like a break to your emotional accelerator pedal. When you don’t get enough sleep, that connection is actually severed and there’s a consequence. You become almost all emotional gas pedal and too little frontal lobe regulatory control brake.
There are many different ways in which sleep generally and very specifically seems to regulate our brain. I could also speak about the different ways that sleep actually reboots multiple systems within the body. That’s certainly the ways in which it refreshes your brain.
[0:21:13.5] MB: I want to dig into learning productivity and the emotional aspects. But before we do, tell me briefly about the physiological and the body reset aspects of sleep as well.
[0:21:25.3] MW: Firstly, we know that deep non-REM sleep that we described is perhaps one of the best forms of blood pressure medication that you could ever imagine. It’s during that deep sleep that your heart rate actually drops, your blood pressure will lower. There are a variety of restorative chemicals and hormones that are released, a growth hormone in particular to actually restore the cells within the body. It’s fantastic for the cardiovascular system.
We also know that it regulates your metabolic system, specifically it regulates insulin levels. If you’re not getting sufficient sleep, your blood glucose actually starts to become disrupted. There are [inaudible 0:22:07.7] that is now taking healthy people with no signs of diabetes. After one week of five to six hours of sleep a night, their blood sugar is disrupted so profoundly that their doctor would subsequently classify them as being pre-diabetic. That’s how critical sleep is to maintaining the metabolic system.
We also know that sleep is essential for another one of the major systems, the reproductive system. Here I’ll speak frankly about testicles, because we know that men who are routinely getting just 5 to 6 hours a night have significantly smaller testicles than those who are sleeping 8 hours or more.
In addition, men who report getting just 5 or 6 hours of sleep each night have a level of testosterone, which is that of someone 10 years their senior. In other words, a lack of sleep will actually age you by a decade in terms of that aspect of wellness and virility. We see very similar impairment in equivalent reproductive hormones and health, of course by a lack of sleep. It’s not just males who are disrupted in that way.
There are a variety of systems within the body. It also regulates appetite and weight and your food consumption. We know for example that those individuals who are not getting enough sleep will have an imbalance in the two hormones that control your hunger and your food intake. Those two hormones are called leptin and ghrelin.
Now leptin sounds like a Hobbit, I know, but trust me they are actually real hormones. Leptin is the hormone that tells your brain you’re satisfied with your food. You’re no longer hungry. You should stop eating. Ghrelin is the antithesis of that. Ghrelin will actually signal to your brain that you are not satisfied by the food that you’ve just eaten, that you are still hungry and that you should eat more.
People who are put on a regiment of just 5 or 6 hours of sleep for one week will have a mocked reduction in leptin, the hormone that says, “You’re fine. You’ve eaten enough, you can stop eating. You’re not hungry.” A mocked increase in the hormone ghrelin, which tells you, “You’re not satisfied with your food. You’re hungry and it’s time to eat more.”
That’s why people will actually eat somewhere between 3 to 500 calories more each day when they’re not getting sufficient sleep. You should also know by the way, it’s not just that you eat more, but what you eat is non-optimal when you’re sleep-deprived. Without sufficient sleep, you actually reach for the heavy-hitting starchy carbohydrates, as well as high-sugar foods and you stay away from the protein-rich foods. In other words, you’ll find yourself reaching for another slice of pizza rather than leafy greens, kale and beans.
It’s not just that you eat more. It’s what you eat that is also detrimental too. I hope that gives people just a little bit of a few brush strokes in terms of the bodily consequences. The one that we probably haven’t mentioned though, which is perhaps most impacted is your immune system. We know that one night of 4 hours of sleep will drop critical anti-cancer fighting immune cells called natural killer cells by 70%, which is a truly remarkable state of immune-deficiency, which happens very quickly within just one night.
Secondly, we also know that the link between a lack of sleep and cancer has now become so strong that the World Health Organization recently classified any form of night-time shift work as a probable cause energy. In other words, jobs that may induce cancer, because of a disruption of your sleep rate rhythms.
We can look to more benign things too. We know that if you’re getting just 5 hours of sleep in the week before you go and get your flu shot, you will only produce 50%, or in fact, less than 50% of the normal antibody response, rendering that flu shot largely ineffective.
Finally, know that if you’re getting just 5 hours of sleep a night, you are 2 to 300% more likely to capture cold, than someone who is getting 8 hours of sleep a night. This was a remarkable study where they quarantined people in a hotel and they had tracked how much sleep that they were getting in the week before. Then they flushed up the nose of all of these individuals; the flu virus. Then in the next few days they looked to see how many of those individuals succumbed to the flu, how many got infected. Then they bucketed them on the basis of how much sleep that they had in the week before, and that’s how they were able to come to that conclusion.
There really isn’t any system within your body, or process within the brain that isn’t wonderfully enhanced by sleep when you get it, or demonstrably impaired when you don’t get enough.
[0:27:25.3] MB: What a powerful statement. I mean, just that sentence alone really succinctly summarizes the fundamental conclusion that the science is in across nearly every spectrum of the body, the brain, etc., that sleep is incredibly valuable. That 8 hours of sleep specifically is really critical.
[0:27:46.2] MW: I think it is. I think what we know is that without sleep, there is low energy and disease. With sleep, there is vitality and health. The sleepless epidemic is perhaps the greatest curable disease that no one is really talking about, or effectively trying to solve. I would simply say that the lack of sleep is both the most striking omission in the health conversation of today. All lack of sleep is perhaps a slow form of self-Euthanasia.
[0:28:16.6] MB: I want to dig back into the relationship. Let’s touch on learning and memory. Tell me a little bit more about the work you’ve done and some of the research around how sleep can improve learning and memory.
[0:28:29.8] MW: Sleep actually is beneficial for memory in at least three ways that we’ve now discovered and this is the work that we’ve been doing, or some of the work that we do at my sleep center.
First, we know that you need sleep before learning to essentially prepare your brain; perhaps a little bit like a dry sponge, ready to initially soak up new information the next day. We did a study where we tested a very simple hypothesis. Is it wise to pull the all-nighter? Is it a good thing, or a bad thing?
We took a group of individuals and we either gave them a full night of sleep, or we kept them awake throughout the night. Then the next day, we wedged them inside an MRI scanner and then we have them try and learn a whole list of new facts as we were taking snapshots of brain activity. Then we tested them to see how effectively that learning had been.
Firstly, what we found is that when we put those two groups head to head, there was a 40% deficit in the ability of the brain to make new memories without sleep, and just a frame that in context it would simply be the difference between acing an exam and failing it miserably. What we went on to discover from the brain scans however was why the brain was failing to lay down those new memories.
There is a structure in our brains, on the left and the right side called the hippocampus. You can think of the hippocampus a little bit like the memory inbox of the brain. That it’s actually very good at receiving new memory files and holding on to them initially.
When we looked at that structure in those people who’d had a full night of sleep, we saw lots of healthy learning-related activity. Yet, in those people who were sleep deprived, we actually couldn’t find any significant activity whatsoever.
It was almost as though sleep deprivation had shut down your memory inbox as it were and any new incoming files. They were just being bounced. You couldn’t effectively commit new experiences to memory. If people would like to just understand what that means in terms of the hippocampus, I’m sure many people listening have probably seen the movie Memento. In that movie, that gentleman has damage to the brain and specifically to the structure of the hippocampus. From that point forward, he can no longer make any new memories. It is what we call in neurology, densely amnesic.
That part of his brain was the hippocampus and it is the very same structure that your lack of sleep will actually attack and prevent your brain from actually laying down and placing those new memories into a fixed state within the brain. That’s the first way that sleep is good for learning a memory.
You also need sleep not just before learning, but also after learning, but for something different now. Sleep after learning will essentially hit the save button on those new memories. It will essentially solidify those memories into neural architecture of the brain. As we mentioned before, it actually will transfer those memories, almost like packets of information being transferred across the network, from a short-term vulnerable storage site to the more permanent long-term storage center within the brain, which is called the cortex; this wrinkled mass that sits on top of your brain.
That means that when you come back the next day, those memories are protected and safe and you will be able to remember, rather than those memories being vulnerable to being overwritten or lost, for example to the ravage of time. Which mean, that they are ultimately forgotten.
We also know a little bit about how sleep not only transfers memories during sleep, but even strengthens those memories. It’s during sleep that the brain actually replays the information that you’ve recently learned. These are studies done in humans, but also in animals they were actually placing electrodes into the brains of rats and they were having them run around a maze.
As they were running around the maze and learning the maze, all of these different brain cells which fire in a specific signature pattern, which was essentially the imprinting of a memory and it adds different tones to them. It would sound a little bit like “babababam, babababam, babababam.” The brain is imprinting this memory as the rat is running around the maze.
Low and behold, what happens is that when you then let the rats sleep, but keep recording and keep eavesdropping on the brain, what do you think reemerges? It’s exactly the same pattern, “babababam, babababam.” The rat is replaying those memories. What’s incredible however, is that it’s actually replaying them at somewhere between 10 to 20 times faster. Rather than “babababam,” it’s actually, “brrm, brrm, brr, brrm, brrm.” It’s this high-speed fidelity replay. We think that that actually helps score the memory trace into the brain in a strengthened manner, almost like etching on the surface of glass. You’re really strengthening that neural circuit. That’s sleep after learning to strengthen individual memories, and I guess essentially future proof that information within the brain.
There is a final third way that sleep actually helps memory that we’ve discovered, which I think is perhaps most exciting. Sleep doesn’t just simply strengthen individual memories. It’s that strengthening of individual memories by the way that happens during deep, non-rapid eye movement sleep, or dreamless sleep.
Sleep also then actually interconnects those new memories together and interconnects new information with all of your pre-existing back-catalog of autobiographical stored information. Essentially, what sleep is doing and this is actually the work of rapid eye movement sleep of dream sleep, is that you’re starting to collide information together within the brain. This is a bit like group therapy for memories.
What you awake with the next morning is a revised mind-wide web of information within the brain. It’s a new associative network, or at least not a radically new associative network, but it’s an updated and it’s a modified associative network. That’s the reason that you can come back the next day having extracted and divine, creative novel solutions to previously impenetrable problems that you were facing.
It’s probably the reason – I mean, now know this, for example that sleep will actually provide almost a three-fold advantage in problem solving relative to an equivalent time period spent awake. That science is now very well, I think rendered and described.
There probably is a reason that you’re never told to stay awake on a problem and in every language that I’ve inquired about to date, that phrase sleeping on a problem seems to exist. It seems to transcend cultural boundaries. It’s a phenomenon that is common across the globe. I should also note by the way that we – the British, we say you sleep on a problem. I believe and please correct me if anyone knows this, but I believe the French translation is a little closer to you sleep with the problem, rather than you sleep on a problem. I think that says so much about the romantic difference between the British and the French. I’ll digress before I lose my British passport.
[0:36:22.5] MB: That’s great. Yeah, that’s a funny anecdote and probably true. I’ve seen the phrase creative incubation and some research around creativity, and some of the science behind what you’re describing. To me, it makes so much sense that the more you give the brain the ability to something, and when you come back to that problem, you’re going to be much more creative. You’re going to be much more effective at solving.
[0:36:48.0] MW: That’s right. It’s not just sleep by the way. If it’s a complex problem, simple problems tend to benefit from deliberative focused thought. But complex problems, problems where there are maybe 10, 20, 80 different variables and you could think of this as something very crass to you. What type of knife or fork set do you buy? This may be just three or four different variables. Versus, what type of card do you buy, where there is maybe 16 different features of variants that you have to choose between.
Well, the more complex a problem is, the more benefit there is to actually stepping away and stopping consciously thinking about it. That’s where the non-conscious brain seems to go to work. It seems to be able to distill amounts of information that we just can’t consciously juggle all up in the air at the same time when we’re awake. It’s just too much for a working memory.
If you’re to think of perhaps what the extreme version of that non-conscious processing would be, you would probably design a system that looks very similar to sleep. That’s exactly why sleep provides those creative benefits. It’s essentially informational alchemy that occurs overnight.
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[0:39:22.9] MB: I want to segway now and get into strategies for sleeping more effectively. We’ve talked at length about how important sleep is both from avoiding a tremendous amount of negative consequences, but also in producing a myriad of positive benefits. Tell me about, for somebody who maybe has trouble sleeping, or just in general, what are some of the basic interventions that we can implement in our lives to sleep better?
[0:39:50.5] MW: These tips I suppose, and again, I’m not just going to tell you the rules. I won’t just try and explain the reasons for each of these rules. I do warn people that some of them are probably not necessarily desirable. It makes me very unpopular, but here they are.
The first overarching rule of course, is that you just have to carve out an 8-hour non-negotiable sleep opportunity every night. It sounds crass and it’s sounds hokie, but I do this in my life as well. I’m not just saying this because I’ve just written a book and I want to practice what I seem to be preaching. But it’s from a very selfish perspective, because I know the evidence so well. If you knew the evidences I do, which and I hope people will do after reading the book, you just wouldn’t do anything different. I don’t want to short a life, I don’t want a life filled disease and pain and sickness and suffering. That’s why I do give myself a non-negotiable 8-hour opportunity every night.
Once you’ve got that in place – I don’t think it’s insurmountable. People are doing wonderful things in terms of actually committing non-negotiable time to exercise, and people are trying to eat more healthily. I don’t think sleep is a lost cause in this regard.
Once you’re getting that opportunity, then I think there are five things that you could do. If there is one thing that you do from all of these tips, it is these; regularity. Go to bed at the same time and wake up at the same time, no matter what, no matter whether it’s the weekend, or the weekday. Even if you had a bad night of sleep, still wake up at the same time the next day. Accept that it’s going to be a bit of a tricky day. But then just get to bed early the following evening and then you will reset.
Because if you sleep in late for whatever reason, you’re not going to feel tired until later that following evening, and you start to drift forward in time and it’s called social jetlag. That has marked deleterious consequences to your health and to your sleep. Regularity is key.
The second is temperature. Keep it cool. Keep your bedroom around about 68 degrees is optimal for most people, which is probably colder than you think, or about 18 and a half degrees Celsius. The reason is this, that your body needs to drop its core temperature by about a 2 to 3 degrees Fahrenheit in order to initiate sleep. That’s the reason that you will always find it easier to fall asleep in a room that’s too cold, than too hot. Because at least the cold room is moving your brain and body in the right thermal direction, that it actually wants to go to for sound and healthy long sleep.
Try to keep your temperature in the bedroom cool. Wear socks if you get cold feet. Some people complain about this, so it’s okay to wear those socks, but keep the bedroom cool. Another way that you can exploit this hack is actually to take a hot bath before bed, or a hot shower. The bath is better if you look at the evidence.
Most people think that when they have a hot bath, they get into bed, they’re nice and warm and that’s what lets them fall asleep more easily. It’s actually the opposite. When you get into a bath, all of the blood comes from the core of your body out to the surface, that’s why you get that rosy glow. It’s what’s called mass vasodilation.
Once you get out of the bath with all of that blood near the surface of your skin, you have this huge massive thermal dump. You get this evacuation of heat from the body, which plummets your core temperature, and that’s why you’ll fall asleep more quickly and more soundly.
The third tip is the light, and actually darkness more specifically. We are actually a dark-deprived society in all first-world nations. You need darkness to allow the release of a critical hormone called melatonin. Melatonin will time the normal healthy onset of sleep. If you’ve got lots of light inside of the house during the evening, and especially if you’re looking and staring at those LED screens from phones, tablets, laptops etc., that will actually fool your brain into thinking it is still daytime and it will shut off melatonin, so you won’t be releasing melatonin.
There were studies done where they had people reading on an iPad for one hour before bed. If I was doing that here in California, their data demonstrated that my release and peak of melatonin didn’t happen, or were shifted by three hours forward in time. I would essentially be close to Hawaii in terms of my internal clock timing to sleep, rather than California.
Keep it dim. You can turn down half the lights in the house in the evening. You don’t need all of them on the last hour before bed. Also stay away from screens in the last hour, and try and use black out curtains, that can actually be very helpful.
The fourth tip is not to stay in bed if you have been awake for longer than 20 minutes. This applies to whether you’re trying to fall asleep, or whether you’ve woken up and are trying to fall back asleep. The reason is this, your brain is a remarkably associative device. If you are lying in bed awake, it quickly learns that being in bed is about being awake rather than being asleep.
You need to break that association. After 20 minutes or so, if you haven’t fallen asleep, get up, don’t get too stressed, go to a different room and in dim light, perhaps just read a book, no screens, no eating. Only when you feel sleepy should you return to bed. In that way, you will actually relearn the association between your bed being about being asleep, rather than being awake.
I would note that some people actually don’t like the idea of getting out of bed. It’s dark. Maybe they’re warm and maybe it’s colder in the rest of the house. I understand that. Another way to try and help you get back to sleep that has good proven clinical trial data behind it is actually meditation. I’m actually quite hard know a scientist, and when I was looking into this evidence as I was writing the book, I was really quite skeptical.
The studies were very clear, very well done, some of them out of Stanford here just down the way from me. So much so that I actually started meditating myself and that was seven months ago, and I’m now a regular meditator. If I’m traveling going through jetlag, for example and struggling with sleep, I will actually use a meditation relaxation practice.
The final tip is the one that really makes me deeply – well, deeply unpopular, just generally as a person anyway, but this is the one that really makes me unpopular with people. No caffeine after noon and avoid alcohol in the evenings. Forego and I kept and I’ll explain both.
Everyone knows of course that caffeine activates you. It’s a class of drugs that we call a stimulants and it can keep people awake. What people may not know however is that for those people who say, “Well, I can drink an espresso after dinner and I force sleep fine and I stay asleep.” That may be true. However, the depth of the deep sleep that you have when caffeine is swirling around within your brain during sleep is nowhere near as deep as if you had not had that cup of coffee in the evening.
As a consequence, people wake up the next morning. They won’t fee refreshed or restored. They don’t remember having a problem falling asleep or staying asleep. They don’t equate it with the cup of coffee they had the night before. But now they find themselves reaching the two cups of coffee, or three cups of coffee in the morning, which essentially is building a dependency and addiction cycle. That’s the issue with caffeine and that’s why the suggestion is stop caffeine midday and certainly after 2 PM.
Alcohol is probably the most misunderstood drug when it comes to sleep. Alcohol is a class of drugs that we call the sedative hypnotics. Sedation is not sleep. Many people will say, “Well, I nightcap, I have a quick whiskey and it puts me to sleep. It’s great.” It’s actually not true. What you’re simply doing is you’re sedating your cortex, you’re knocking out your brain essentially. You’re not getting into natural sleep.
Then there are two more problems with alcohol. Firstly, it will fragment your sleep so you will wake up many more times throughout the night, which leaves you with what we call unrestorative sleep. The final thing is that alcohol is one of the best chemicals that we know blocking your dream sleep, your REM sleep, which is essential for not just creativity and that associative type of memory processing that we spoke about.
REM sleep is also critical for emotional and mental health. It is during REM sleep when we provide our brain a form of emotional first aid, and you won’t be getting that if you’re blocking REM sleep by way of alcohol. Those would be the five tips to better sleep and hopefully they help some folks. I’m also happy to speak a little bit about sleeping pills. They’re also misunderstood, but those would be for most people the five tips that I would offer.
[0:49:17.9] MB: Great advice. I try to implement as many of those as possible. One of the things, specifically caffeine is something that I used to drink at my peak. About a cup of – I mean, a pot of coffee a day. Now I basically don’t consume any caffeine. When I do, I limit myself, no caffeine afternoon. Maybe one cup of tea is the maximum. I’ve noticed a huge impact on that impact in my sleep. Sorry, were you going to say something?
[0:49:44.6] MW: Yeah. I’m just going to say, I mean it’s immensely wise and it’s one of the problems with a lack of sleep is that you quickly reset your perception of your effectiveness and your health. You just think, “Well, this is how I am now at this age.” Not realizing that you could actually be a far better version of yourself, both mentally, cognitively and physiologically if you were just to start getting sufficient sleep.
I think many people fail to realize that with caffeine especially that it’s only when they come off caffeine do they really start to feel both the benefits of all of the side effects that normally come with high caffeine use, but especially the benefits on sleep. It’s like wiping a fogged window and you finally can start to see clearly through it. That’s the benefit of a full restorative night of sleep.
[0:50:36.8] MB: I have a couple short questions all around specific sleep strategies or tactics. Let’s start with – you touched on sleeping pills. Tell me about sleeping pills. Do they work? If so, why or why not?
[0:50:50.2] MW: There are no sleeping medications that we have currently that produce naturalistic sleep. The current class of drugs that you will be prescribed are called sedative hypnotics. Again, as we mentioned with alcohol, sedation is not sleep. The sleep that you have when you’re on sleeping pills, if I were to show you the electrical signature of your sleep if you would come to my laboratory, it would not be the same on sleeping pills as it would be if you’re just having naturalistic healthy sleep. That’s the first thing.
The second thing, and I go to great lengths and a whole chapter in the book to discuss this, is that people are probably not aware of the risks of sleeping pills. They have not been communicated to public adequately. Firstly, we know that sleeping pills are associated with a far higher risk of death. They’re also associated with a significantly high risk of cancer and infection.
Now, we don’t yet know if this is causal versus simply associational, but what I wanted to do is to try to get that information out to the public, so they at least could be armed with the knowledge and make an informed choice with that doctor when they go and see the surgery. That’s I think one of the biggest problems of sleeping pills is that the misunderstood nature about what they give you and the dangers.
People also don’t necessarily have to be taking sleeping pills, I should note. There is a safe and non-pharmacological alternative which is just as effective. It is called cognitive behavioral therapy for insomnia, or CBTI for short. You work with a therapist for a couple of weeks. As I mentioned, it’s just as powerful as sleeping in the short-term, but better still, once you finish that short therapy phase, you continue to maintain that better sleep. Unlike sleeping pills, when you come off those you tend to actually have what’s called rebound insomnia, where your sleep is as bad, if not worse than when you started.
I think people can revisit their sleep issues with their doctor. I’m not trying to shame people who are on sleeping pills. I’m not trying to make you feel bad if you are. I’m very sensitive to the desire for better sleep and I’m so sensitive to the issue of insomnia, or the desperate, desperate state. You should be aware of what sleeping pills are, what they do and what the alternatives are.
[0:53:15.8] MB: What about taking a melatonin supplement?
[0:53:18.6] MW: Melatonin is useful in the circumstance of jetlag to try and reset your body clock in a new time zone. You should take it 30 to 60 minutes before you want to get to sleep in the new time zone. Melatonin works to essentially time the onset of your sleep. I guess, the analogy would be if you think about the 100-meter race in the Olympics. Well, melatonin is the starting official who has the starter gun.
It’s melatonin that brings all of the different ingredients off the sleep race to the starting line, then starts the race in its entirety. It begins the sleep race. Melatonin itself does not actually participate in the race of sleep, in the generation of that sleep race. That’s a whole different set of chemicals. As a consequence, that’s why actually melatonin when you are in a new time zone and you’re stable now in that new time zone, if you’re a young healthy individual, then melatonin actually isn’t effective as a sleeping aid. It doesn’t actually help if you look at the studies.
That said, I would note that for those people who are taking melatonin and they feel as though it helps their sleep, well then I usually tell people continue on. It’s because the placebo effect is one of the most reliable effects in all pharmacology. No harm, no foul if you think it’s working for you.
[0:54:48.1] MB: What about napping? Is napping something – if you’re sleep-deprived, can you catch up with a nap?
[0:54:53.7] MW: Unfortunately, you cannot catch up on sleep. Sleep is not like the bank. This is another myth that I try to deconstruct in the book. You can’t accumulate a debt, let’s say during the week and then hope to pay it off at the weekend. Sleep just doesn’t work like that. There is no credit system, or there is no credit sleep sell within the brain.
You can if you are sleep-deprived, take a nap and overcome some of the basic sleepiness. Your reaction times will improve a little bit after a nap, but you don’t actually overcome all of the higher level, cognitive issues such as decision-making, learning in memory, focused attention, all of those types of things that we know are would buckle and collapse by way of a lack of sleep. Naps just don’t seem to be able to overcome those.
You can’t overcome – you can’t bank sleep and you can’t sleep off a debt. I see this in my students. It’s what I would call sleep bulimia, which is where they’re binging on sleep at the weekend and they’re – try and taking too little sleep during the week. It’s this binge purge kind of cycle.
I would also say naps, just more generally are a double-edged sword. If during the day when we’re awake, we actually build up a chemical pressure in our brain. It’s a sleepiness pressure. Now, it’s a hydraulic pressure, don’t worry. As I said, it’s a chemical pressure. The chemical that builds up is called adenosine. The more of that sleepiness chemical that you have, the more and more sleepy that you will feel. After about 16 hours of being awake, you’re nice and tired and then you should fall asleep and stay asleep for about 8 hours.
When we sleep, we remove that sleepiness pressure. It’s almost like a valve on a pressure cooker. We release that sleepiness steam as it were. This is where I come back to naps. If you nap too late in the day, you actually release some of that healthy sleepiness, which means that when it comes time to sleep normally at night, you may actually struggle to fall asleep, or at least stay asleep.
The advice would be this, if you are someone who can nap regularly and you don’t struggle with your sleep at night, then naps are just fine. But if you can’t nap regularly and/or you’re having difficulties with your sleep at night then the advice is you shouldn’t nap, you should stay awake, build up that healthy sleepiness, and then you will have a better night of sleep because of it.
[0:57:30.1] MB: What about someone who’s in a situation, let’s say like a new parent. Is there anything that they can go through obviously, very chronically sleep-deprived state? Is there any strategy for them to be able to implement, that would help them battle through that in some way?
[0:57:45.0] MW: Some parents describe trying to work better shifts and what I mean by that is in two ways. Firstly, some parents will try to take early, the early shift and then the late shift, the first half of the night versus the second half of the night and switch between those two. Another way that you can do that on an informed choice is try to determine whether you are a night owl, or you’re a morning type, what we call a lock. That’s a genetically predisposed. It’s called your chrono type.
If you are someone who likes to go to bed late and wake up late, versus someone who likes to go to bed early and wake up early, that’s not a choice. That’s a genetic mandate that’s being given to you in your DNA code. You can try to ask in the couple, are you someone who would prefer to wake up early and go to bed early? In which case, could you take the morning shift, the late morning shift?
If I’m someone who likes to go to bed late and wake up late, well then it’s easier for me to actually take the first half of the night and then sleep for the second half of the morning and sleep late. You can think about split shifts like that. Some people will also flip-flop back and forth. Some people will say, “Well, I’ll take the next two nights and you get good sleep, then we switch over and you take two nights.” They try to mix and match it in that way too. It’s a desperately difficult situation.
In part, we would not actually design to be family units like this, if you look at [inaudible 0:59:17.8] tribes who have not been touched by the electrical influence, then they actually tend to sleep in groups. Restless legs dangling all over the place, arms intertwined. Whole families would sleep together and people would take turns in terms of caring for the young. It’s a lot to ask of parents, and those are some of the ways that you can try to overcome it.
[0:59:45.6] MB: One other question and this is out of left field a little bit. I’m curious, have you seen or studied around the neurotransmitter GABA and its relationship with sleep?
[0:59:56.5] MW: GABA is the principle inhibitory neurotransmitter of the brain. The way that most sleeping medications work right now and you can just name your favorite one and it will work in this way, is by essentially trying to activate the receptors in the brain for GABA. Those receptors essentially are like the red lights on your neurons. They stop them firing, they stop them from going.
Drugs that try to target the GABA system within the brain are really quite blunt instruments and that’s why sleeping pills, which act exactly in this way are really not precise tools. Sleep is a remarkably complex neuro-physiological and neuro-chemical ballet if you look at it. All of these different stages of sleep, neurotransmitters going up and down and brain networks ebbing and flowing.
To think that you can essentially recreate something that is so complex and so bi-directional sleep by simply just knocking the brain out and switching it off using GABA receptors is really just – it’s an unfortunate outcome of how poor our pharmacology is in this day and age. We just don’t yet have the pharmacological precision and sophistication to mimic sleep at this stage.
[1:01:22.4] MB: What’s one piece of homework that you would give to a listener who wants to sleep better?
[1:01:28.5] MW: I would say try giving yourself one week of 8 hours of sleep and see if you feel any better. Just give it as self-improvement test. Try it as a hack, that if you are one of those people who are into the quantified self-movement and you’re into self-experimentation then just test out all of that what you’ve just heard in the past week and just determine if you feel any better when you’re sleeping 8 hours every night and you’ve regular each and every night. Versus a staccato sleep schedule where you’re sleeping 5 hours and 6 hours and 12 hours and then 5 hours again. Just ask yourself, “Did that experiment work? Is it in my favor? Do I feel any better and do I notice that improvement?”
[1:02:19.2] MB: For listeners who want to learn more and want to find you and your book online, what’s the best place to do that?
[1:02:25.9] MW: They can find the book, which is called Why We Sleep. They can find that online. Amazon holds it. You can find it from all of your major bookstores, both the major brands, as well as all of the independent. It’s on the list of most libraries too. If you don’t want to part with your money, my publisher would probably won’t like me saying that, but I read online, it’s about the knowledge of the book, not the sales.
If you want to learn more about the work that I do, you can follow me on social media. I am at sleepdiplomat, all one word. Sleepdiplomat. I’m on Twitter and also you can find me on LinkedIn. Also on the web I am at – it is www.sleepdiplomat.com.
[1:03:11.4] MB: Well, Matt. This has been a fascinating conversation. So much great information, practical strategies, tons and tons of science. Really appreciate it. Incredible insights. Thank you so much for coming on the show and sharing all of these wisdom.
[1:03:25.4] MW: Well, thank you and I have to say a real thanks to you too. It’s not just what people say at the end of these interviews, but I’m trying to fight this battle for sleep. I can only do so much by getting on shows or television, radio or writing a book for example. I need fantastic journalists and media and genius types to actually join and partner with me to get this message out. I too just want to thank you, Matt. Thank you for being part of the sleep mission.
I’m going to grant you now the title of being a sleep ambassador for having me on the show. Thank you very much. Sincerely, I really want to thank you. I desperately need to get this message out. This portal is a remarkable way to proclaim the virtues of sleep. Thank you.
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