Stay ConnectedThe Matt Walker Podcast is all about sleep, the brain, and the body. Matt is a Professor of Neuroscience at the University of California, Berkeley. He is the author of the book, Why We Sleep and has given a few TED talks. Matt is an awkward British nerd who adores science and the communication of science to the public.
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Copyright: © 2025 The Matt Walker Podcast
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In the second episode of this series about REM sleep dreaming, Matt explores what the science has to say not only about how we dream at the brain level, but what it is that we dream about.
Traditionally, civilizations such as those in ancient Egypt, believed that dreams were a form of divine intervention--a message from the heavens. Thereafter, Matt discusses Sigmund Freud, who introduced the notion of dreams originating from within the brain, not the heavens, and thus could be considered a science of the brain/mind. However, Freud went on to develop the (non-scientific) theory that dreams reflected the expression of our subconscious desires, but that those repressed wishes were transformed and disguised by the brain into a dream narrative.
Freud's theory suggests that, as we dream, our repressed wishes pass through a sensor in our mind, and then come out the other side as unrecognizable experiences to the dreamer. Freud believed that he understood how the sensor worked and could decrypt the disguised dreams, and thus know something about his patients that he could share with them. Matt notes that Freud's theory could never be proven right, nor wrong, and also why we no longer consider it as a valid scientifically rigorous theory.
Next, Matt delves into modern-day scientific methods that have led to new theories of why we dream, including a theory that dreams are a replay of our waking life experience of our past memories.
He recounts the work of his friend, Dr. Robert Stickgold, who found that only 1 to 2% of our dreams are really true clear replays of our prior waking life events. Matt also notes that, based on the same findings, there is a red thread narrative that runs from our waking lives into our dreaming lives = emotional concerns that we're having during the day, and the social individuals connected to those things.
Matt describes the latest research from a team in Japan that used MRI scans to predict the content of dreams. Matt postulates that science is getting ever closer to having the ability to know exactly what we are dreaming, and perhaps, take away ownership of the dream process from the dreamer itself.
Matt draws this episode to a close by asking some thought-provoking questions about whether we are truly responsible for what we dream about, and whether we should be held responsible for what we dream.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at Athletic Greens are the sponsors of this week’s episode, and they are generously offering three benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals and biotics, together with essential vitamins. Matt’s been using it for several years now, first because he’s serious about his health and uses it as a full nutritional insurance policy, and second, because Matt did his research on the science and ingredients in Athletic Greens and thinks it’s science and scientific data that can be taken as ground truth.
So, make your way over to Athletic Greens, and take advantage of this incredible deal. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
This week’s episode is the first in a new multi-part series all about dreams! Today, Matt focuses on the question of how your brain generates these things called dreams.
Matt starts with an unexpected statement: last night, when you were dreaming, you became psychotic. 5 things happen when you dream that justify his diagnosis: 1) you see things that aren’t there, 2) you believe things that could not be true, 3) you become confused about time, place, and person, 4) you have wildly fluctuating emotions, and 5) you wake up in the morning and forget most of this dream experience, amnesia. If you experience any of these symptoms while awake, you might seek psychological attention. Yet, dreaming is both a normal and, essential biological and psychological process.
Matt explains that REM sleep is not the only stage of sleep when we dream. However, the things that most of us call dreams, involving movement, emotions, past memories, and rich narrative, largely come from REM sleep.
Over the past 20 years, a new scientific view of REM sleep has given rise to an understanding of 3 basic questions regarding dreaming. 1) how does the brain create this neural activity called dreaming? 2) can we explain if dreams have their source in our experiences, or are they de novo experiences generated by the brain? 3) what is the function of REM sleep dreaming? The advent of brain-imaging machines allowed scientists like Matt to create beautiful 3D visualizations of people’s brains as they dreamt.
When the brain switches from deep non-REM sleep over to REM sleep, something remarkable happens: the brain erupts with spikes of activity in the MRI scans. Specifically, 4 areas of the brain fire up when dreaming starts during REM sleep: the visuospatial regions, the motor cortex, the hippocampus, and the amygdala. In contrast to all of these areas, one part of the brain does the opposite. The left and right sides of your prefrontal cortex becomes markedly deactivated during REM sleep. This is important because your prefrontal cortex controls logical reasoning. This is, in part, why dreams are often filled with movement, strong emotions, past memories, people, and experiences, yet are utterly irrational.
Finally, Matt reminds us of one last fact. When we are in REM sleep dreaming, the body is paralyzed, preventing us from acting out our bizarre dreams. Otherwise, we would put ourselves in danger and be popped out of the gene pool rather quickly!
Be sure to tune in for the rest of the series to uncover even more fascinating information about these things we call dreams.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at InsideTracker are the sponsors of this week's episode, and they are generously offering a special 31% off any one of their programs if you use the above link during the time window of this particular episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
Matt has a special announcement this week: a new recurring type of episode called, ‘Sleep is Bloody Remarkable’. This series of episodes will share fascinating facts about sleep that will blow your mind! In the premier episode, Matt focuses on something truly (bloody) remarkable: half-brain sleep, or unihemispheric sleep.
Unihemispheric sleep is the phenomenon of when one hemisphere of the brain is awake, while the other sleeps. Matt goes on to discuss how the two sides of the brain rotate their sleep roles, such that after a set period of time, the side that got to undergo sleep first wakes, so that the other half of the brain gets its needed opportunity for sleep.
Whales and dolphins are great examples of half brain sleepers. They need to maintain movement in their underwater environment. Half-brain sleep allows them to still do this while still getting plenty of NREM slumber (just one half of the brain at a time). Birds are also capable of half-brain sleep. Birds use unihemispheric sleep for survival purposes, although for different reasons. Birds use it to keep one eye on things, literally!
When birds land as a flock, the birds on the farthest left and right sides - the sentinels, as it were - undergo unihemispheric sleep, to keep one eye open for threat detection on their respective side (180 degree views on the left and right). The result being, combined, the entire flock gets full 360 degree panoramic threat detection. Indeed, all of the rest of the birds are allowed to sleep with both hemispheres i.e., full brain sleep.
The poor birds on the sides don’t actually get the chance to come into the middle of the flock, it seems. Instead, to get equal sleep on both sides of the brain, when one hemisphere has fulfilled its sleep need, these birds will rotate 180 degrees, and switch sides of the brain that is sleeping. Bloody remarkable!
We humans undergo our own rendition of unihemispheric sleep…sort of =) In an unfamiliar location, such as a hotel room, humans keep one of their hemispheres on guard in this potentially dangerous context. Meaning, one half of the brain does not go into as deep NREM sleep, almost as if it is remaining semi-conscious. Matt also notes that half-brain sleep only happens during NREM sleep. When all species go into REM sleep, both sides of the brain sleep. There is no unihemispheric dream sleep, it seems.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at Athletic Greens are the sponsors of this week’s episode, and they are generously offering three benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals and biotics, together with essential vitamins. Matt’s been using it for several years now, first because he’s serious about his health and uses it as a full nutritional insurance policy, and second, because Matt did his research on the science and ingredients in Athletic Greens and thinks it’s science and scientific data that can be taken as ground truth.
So, make your way over to Athletic Greens, and take advantage of this incredible deal. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
Matt returns with Part 2 of his series on sleep and weight gain. This time around, he teaches us how a lack of sleep not only makes you eat more food, but changes what types of food you want to eat, and eat to excess.
First, Matt describes how underslept individuals that are limited to 4-5 hours of sleep for several nights will experience a 33% increase in the desire to eat obesogenic, sugary treats. In addition, they will suffer a 30% increase in craving for heavy-hitting carbohydrates, like pasta and pizza, and a 45% increased desire for salty snacks!
Matt goes on to explain that your brain plays a role in this sleep loss-weight gain equation. In one of his experiments, a group of normal, healthy-weight individuals went through the study twice: once when sleep-deprived and once after a full night of sleep. After each condition, the individuals were placed inside an MRI scanner and shown different food types, and asked to rate how much they wanted each food item.
What they found is that the sleep-deprived brain changed markedly, shifting to a pattern of activity associated with what is called hedonic eating, or impulsive eating. Specifically, the prefrontal cortex, which is responsible for impulse control, was shut down by lack of sleep. As a result, the very primitive deep brain regions that drive excessive appetite become hyperactive and hyper-responsive to highly desirable, unhealthy food items, such as ice cream and donuts, rather than nuts or leafy greens.
He also reveals that staying awake across the night doesn't burn vastly more calories. You only burn about an extra 140 calories by staying awake all night relative to being asleep, yet you will eat more than twice that amount more in calories when sleep-deprived. Plus, you are less active when sleep-deprived, so you don't burn off those calories.
Worse still, Matt tells us that dieting becomes ineffective without sleep: 60% of the pounds you will lose come from lean body mass (such as muscle), and not fat. Specifically, when you are sleep-deprived, the body becomes especially stingy with fat, stubbornly refusing to give it up. In other words, you end up losing what you want to keep, which is muscle, keep what you want to lose, which is fat. Also, inadequate sleep increases levels of cortisol, which also makes your body store food as fats.
Matt concludes with an optimistic note by highlighting the fact that getting enough sleep is a scientifically proven way to help you regulate your appetite and a healthy body composition (a little bit less painful than going to the gym!?)
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at InsideTracker are the sponsors of this week's episode, and they are generously offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is essentially a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
Matt kicks off a two-part series all about sleep, eating, and weight gain.
He starts by introducing two appetite-regulating hormones: leptin and ghrelin. Matt explains how leptin sends a signal of fullness, to your brain. When leptin levels are high, your appetite is reduced, and you feel satisfied by the food you eat. Ghrelin does the exact opposite. It revs up your hunger, so when your ghrelin levels are high, you don’t feel satisfied by the food you ate, so you want to eat more.
Matt tells us that when you’re not getting enough sleep, the levels of these two hormones are affected in unfortunate ways, causing you to feel less full and more hungry. Specifically, sleep loss decreases leptin levels by 18%, yet increases ghrelin levels by 28%!
So when you are not getting enough sleep, the body losses the fullness signal AND suffers an increase in hunger levels. The combined consequences? Your appetite rockets up!
It’s also been discovered that levels of endocannabinoids --a class of cannabinoids we naturally produce ourselves -- increase sharply in response to a lack of sleep. As a result, your hunger levels increase even more (as you may know, cannabinoids are part of the reasons that cannabis gives you the munchies).
Adding up all of these effects, Matt describes how this lack of sleep causes people to consistently overeat. Usually somewhere between 250 to 400 extra calories each and every day!
Snacking also becomes a problem. For example, if you present a group of people with a large meal of over 1,000 calories, then give them the option to keep snacking, under-slept individuals will continue to snack, consuming an additional 200 to 300 calories relative to those who’ve been getting a full eight hours of sleep.
This all begs the question: is there a reason why your hunger goes into overdrive when you are under-slept? Matt explains one plausible theory from an evolutionary perspective, based on the fact that when animals are in a starvation state, the brain keeps them awake longer so they can forage further. Therefore, when the brain doesn’t get enough sleep, it thinks we may be in a state of starvation and increases our desire for food.
Finally, notes what's coming in part two: that insufficient sleep not only increases how much you eat but changes your food preferences, and changes how your bodies deposit the extra calories we take on as our hunger increases, relevant to body fat accumulation.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at Athletic Greens are the sponsors of this week’s episode, and they are generously offering three benefits for anyone who uses the above link for their first order: 1) a discount on your order, 2) a one-year free supply of vitamin D, and 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals, and biotics, together with essential vitamins. Matt’s been using it for several years now, first because he’s serious about his health and uses it as a full nutritional insurance policy, and second, because Matt did his research on the science and ingredients in Athletic Greens and thinks it’s science and scientific data that can be taken as ground truth.
So, make your way over to Athletic Greens, and take advantage of this incredible deal. And, as always, if you have thoughts you’d like to share, please reach out to Matt on
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In the previous episode, Matt described the role of temperature in helping us fall asleep. In this episode, Matt teaches us all about the role of temperature in helping us stay asleep across the night, and then more effectively wake up the following morning.
First, Matt takes us back to the body temperature suit experiments that were able to warm or cool different parts of the body. Matt explains that, using this same method, when you continue to cool the body throughout the first and middle parts of the night, enhance the ability of individuals to stay asleep more soundly across the night, increase the amount of deep sleep, and boost the electrical quality of that deep sleep.
Matt explains why a warm bath or shower before bed helps you sleep, perhaps for the opposite reasons you think. It is not that you get warm and toasty ready for bed. Instead, when you get out of the bath or shower, all of the blood races to the surface of your skin. As a result, your core body temperature plummets, enabling you to fall asleep faster and stay asleep more easily.
Matt also discusses how external ambient room temperature impacts our sleep at night. He notes that the optimal temperature for sleep at night for the average adult is between 16-18 degrees Celsius, or 61-65 degrees Fahrenheit, although everyone will be a little bit different, of course.
Finally, Matt explores the effect of temperature on waking up. He notes that as you move into those late morning hours of sleep, particularly as you start to enter the REM sleep-rich phases of your sleep cycle later in the morning, your central brain temperature rises significantly.
Indeed, it is in the last 30 minutes before people would naturally wake up in the morning that their body temperature starts to increase markedly. Matt goes on to describe how this increase in temperature is a signal that triggers the beginning of the awakening process.
Related to this, Matt notes that waking up can be challenging for many people, especially if you're not sleeping in synchrony with your chronotype. However, Matt suggests that one way you can facilitate the process of waking up more effectively is by trying to warm up the ambient temperature of the bedroom in the last 30 minutes before your alarm goes off. So if you have a smart thermostat, try to program it to increase the temperature to around 21 degrees Celsius or approximately 70 degrees Fahrenheit in the last 30 minutes before your alarm goes off.
The bottom line is that many of us don’t realize how important temperature is to falling asleep, staying asleep, and enjoying an enlivened awakening the next morning.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at InsideTracker are the sponsors of this week's episode, and they are generously offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is essentially a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In today's episode, Matt reveals how 1) your own temperature and, even more precisely, 2) the temperature of different parts of you, as well as 3) the temperature of your bedroom, can change how well or how poorly you sleep at night.
Matt describes the basic physiology of how your brain and body needed to drop their core temperature by about 1 degree Celsius, or about 2 to 3 degrees Fahrenheit, for a person to fall and stay asleep across the night. This is the reason why we will always find it easier to fall asleep in a room that's too cold than too hot because the room that's too cold is at least taking you in the right temperature direction for good sleep at night.
Matt teaches us that, ironically, one important way to drop your core body temperature is to warm up your extremities, specifically your hands and feet. He explains that it's one of the key ways your body regulates temperature.
To drive his point home, Matt points to research showing that if you gently warmed the paws of rats, it encourages the blood to rise to the surface of the skin of those paws, away from the core of the body. By emitting heat away from the body's center, it drops core body temperature rapidly, and as a result, the rats drifted off to sleep far faster than was otherwise normal.
Matt complements all this with a study in humans using a whole-body temperature sleeping suit, a little like wetsuit, but with tubes throughout that can warm or cool different parts of the body with warm or cool water.
In the first series of studies, researchers selectively warmed the feet and the hands by just a small amount, which caused a rising of the blood to the surface of the skin. As they warmed the body's extremities, the core temperature of the participants dropped, and the upshot was that these healthy individuals were falling asleep 20% faster than was normal.
In the second round of studies, even more remarkable, if you manipulate the temperature in this way in older adults, they will fall asleep 18% faster than typical, and insomnia patients will fall asleep a full 25% faster than usual with this same method.
The impact of temperature on sleep is therefore clearly significant, but there is even more to this thermal story, including how you can best wake up from sleep feeling alert, which is what Matt will discuss next episode.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The episode is sponsored by the wonderful folks over at Athletic Greens, who are providing a discount and free product if you use the link above. Athletic Greens is a comprehensive daily nutritional beverage containing 75 vitamins, minerals, and whole food-sourced ingredients, including a multivitamin, multimineral, probiotic.
So, head on over to Athletic Greens and get a free year supply of Vitamin D and 5 free travel packs today. Finally, if you have thoughts or feedback you’d like to share, please reach out on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In today's episode, Matt takes us on a deep dive into melatonin. He covers four main topics: 1) what is melatonin? 2) how does melatonin work? 3) what does melatonin do, and *not* do, for sleep? 4) how can we think about melatonin supplementation?
First, Matt describes that melatonin is a naturally occurring hormone released by the brain. He gleefully notes that melatonin is often called, “the vampire hormone” as it comes out at night. In doing so, it signals that it is nighttime, which in turn helps schedule sleep.
Second, Matt explains that, during the day, light enters your eyes, and inhibits the release of melatonin. This absence tells your brain that it's daytime and time to be awake. Fast-forward to the evening, and the arrival of darkness, the floodgates of melatonin release open up. We need darkness in the evening to trigger this release, and, in turn, tell your brain that it's nighttime and time to sleep.
Matt highlights one significant problem of the present age: we live in a dark-deprived society. Many of us get too much artificial light, and not enough darkness. He shares a tip to dim down half of the lights an hour before bed and avoid screens.
Third, Matt elaborates on what melatonin does and does not do; that is, melatonin helps schedule the *timing* of your sleep but does not significantly change the *quality* of sleep. He uses the analogy of a race, where melatonin would be the official who begins the great sleep race but does not participate in the race itself.
Finally, Matt discusses supplementation. You can buy melatonin in certain countries to try to use it as a sleep aid. Based on scientific data across the past 15 years, Matt notes that melatonin isn't as effective as you may think: a recent meta-analysis discovered that melatonin only increases the speed with which you fall asleep by 3.9 minutes, and only improves your sleep efficiency by just 2.2%. This reinforces his point that the role of melatonin is primarily in regulating the timing of your sleep, not in sleep generation.
Matt states that melatonin is not well regulated as a supplement, and that the strength of melatonin that you buy is often unreliable. He describes a study that examined over 15 different suppliers. Strikingly, when tested, the concentration of melatonin within each pill ranged from 83% less to 478% more than what was stated.
Finally, Matt advises that the best way to optimize your sleep is to rely less on melatonin supplementation, and instead, focus on the basics we know make a real difference: sleep regularity, keeping your bedroom cool, getting darkness in the evening, get plenty of natural daylight during the morning, do some physical activity each day, and perhaps most importantly, address your stress and anxiety.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice, nor prescriptive in any way.
The sponsors of this week's episode are InsideTracker. They are offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In this week’s episode, Matt continues his discussion of sleep and caffeine. Here, we learn about the paradox of coffee, one in which coffee provides health benefits, despite its negative impact on sleep.
Before addressing that, however, Matt speaks about one last sleep consequence of caffeine: regardless of your sensitivity to caffeine, it can still disrupt the quantity and electric quality of your deep non-REM sleep.
This can lead to a cycle of caffeine dependency 1) you drink more coffee the next morning to compensate for your poor-quality, unrestorative sleep the night before, which then 2) degrades the quality of your subsequently night's sleep even more, which leads to 3) your potentially reaching for even more sups of coffee the following day, etc, etc.
Matt’s advice to still drink coffee (if you want) is due to the many health benefits associated with coffee. How is it possible that coffee has such health benefits, despite the harmful impact of caffeine on sleep?
Matt points out that the coffee bean itself contains a sizable blast of antioxidants in every cup. In fact, because of the state of the standard Western diet, coffee is the biggest source of antioxidants for many people in developed nations. However, it is possible to get these benefits without drinking caffeine – many health benefits are similarly associated with drinking decaffeinated coffee since that too contains antioxidants.
Therefore, it is the antioxidants in the coffee bean, not the caffeine, that carries the health-related advantages.
But Matt is also clear to speak about the fact that when it comes to coffee, the dose, and the timing make the poison. His advice: try to limit it to one to three (at the max) cups in the morning, remembering the quarter-life of caffeine is around 10-12 hours for the average adult.
By following these steps, you can maintain a healthy relationship between caffeine, coffee, and this beautiful thing we call sleep at night.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The episode is sponsored by the incredible folks over at Athletic Greens, who are providing a discount and free product if you use the link above. Athletic Greens is a comprehensive daily nutritional beverage containing 75 vitamins, minerals, and whole food-sourced ingredients, including a multivitamin, multimineral, probiotic.
So, head on over to Athletic Greens www.athleticgreens.com/mattwalker and get a free year supply of Vitamin D and 5 free travel packs today. Finally, if you have thoughts or feedback you’d like to share, please reach out on Instagram @drmattwalker.
Want to sleep better alongside others doing the same? Come join my Art of Sleep community: skool.com/art-of-sleep
In today's episode, Matt unpacks the world of coffee, and caffeine in the first of a two-part series on caffeine. Matt describes the numerous health benefits associated with coffee, the fact that Matt has even changed his tune a little and advocates a morning cup for some. Matt may not have anything to do with caffeine itself, with more details on that in part 2. In part 1, Matt then takes a deep dive into the different ways in which caffeine negatively impacts your sleep, some of which you may be less familiar with.
The first is that caffeine makes it harder for you to fall asleep. Due to activation of the nervous system, caffeine can lead to that unpleasant experience of a racing mind that won't shut off in bed—almost a Rolodex of anxiety that leads to ruminating and therefore catastrophizing.
The second impact is that caffeine makes it more difficult for you to stay asleep soundly across the night. This is due, in part, to the fact that caffeine makes your sleep more unstable and fragile, so up more frequently at night. The consequence is something that scientists and doctors call sleep fragmentation, meaning that your overall sleep efficiency, or the consistent quality of your sleep, becomes significantly worse when you have caffeine on board.
The third feature that Matt points out centers on caffeine’s duration of action. Caffeine has a half-life of between five to six hours in the average adult. This means that, after five to six hours, 50% of that caffeine is still in your system. What this also means is that caffeine has a quarter-life of approximately 10 to 12 hours for a typical adult.
Here, Matt gives us some context: if you have a cup of coffee at 2 PM, a quarter or more of that caffeine could still be circulating in your brain at midnight. Meaning, if you have a cup of coffee at 2 PM, it may be the equivalent of getting into bed at midnight, and just before you turn the lights out, you swig a quarter of a cup of coffee and you hope for a good night of sleep.
Matt, however, points out that the 10 to 12 hours quarter-life of caffeine is for the average adult, but this varies significantly from one person to the next. He explains in detail why this is the case: based on differences in genetics, different people will have a more or less efficient version of an enzyme that clears caffeine from their system. Some people will have a version of that enzyme that allows them to remove the caffeine from their system very quickly, whereas other people will have a version of the enzyme that is much slower in its speed of clearing caffeine.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.The good people at InsideTracker are the sponsors of this week’s episode, and they are generously offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is essentially a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.
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