The Matt Walker Podcast

By Dr. Matt Walker

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Subscribers: 275
Reviews: 1

Miguel
 Sep 17, 2021
Excellent podcast, I love the entertaining and informative snack sized episodes.

Description

The 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.

Episode Date
# 31: Insomnia - Part 6
1311

Very understandably, many insomnia patients try to self-medicate their condition with varied “sleep aids”. The tragedy us that most of them not only fail to help but actually make insomnia worse.  

Most common among these is alcohol, which hurts your sleep in at least three different ways: 1) it sedates your brain, rather than generating naturalistic sleep 2) it increases the frequency of nighttime awakenings and makes it harder to fall back to sleep, and 3) it inhibits REM sleep.

THC also inhibits REM sleep, and users can develop a dependency on and tolerance to it, requiring more to get the same sleep effect. Worse still, THC is associated with a severe withdrawal insomnia, which only leads to relapse use. 

Another ineffective tool is melatonin. Melatonin does not help people with insomnia sleep, as we discussed in the episode all about Melatonin. 

The other option is classic prescription sleeping pills. However, based on their safety concerns and their minimal effectiveness long-term, the American Academy of Sleep Medicine and the American College of Physicians (ACP) now state that classic sleeping should no longer be the first-line treatment for insomnia. Instead, the first line treatment for insomnia should be the non-drug approach called cognitive behavioral therapy for insomnia (CBTi), and the one that Matt typically advocates for.

At a high level, CBTi involves working with a trained clinician for several weeks to change your habits, behaviors, mental beliefs, and stress around sleep. Many people with insomnia lose all confidence in their sleep and have terrible anxieties around not sleeping—in other words, their sleep controls them, and CBTI is designed to reverse that. 

Many clinical studies have shown that CBTi is just as effective as sleeping pills in the short term yet has no negative side effects. Unlike sleeping pills, its benefits can last for many years after stopping work with your therapist. 

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.

Today’s podcast is supported by MasterClass - the online streaming platform where anyone can learn from the world's best about a variety of topics such as cooking, business, art, entertainment, and, of course, technology. When you sign up, you get access to all of the classes taught by such masters as Martin Scorsese, Venus Williams, Gordon Ramsay,  and Bill Clinton to name just a few of Matt’s favorites. You may even find a masterclass from a familiar sleep scientist! So if you're curious and have a thirst for learning,  head on over to masterclass.com/mattwalker and you will get a discount when you sign up.

Another sponsor of today's podcast is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can fully get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. 

So, make your way over to LMNT and MasterClass to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Sep 26, 2022
# 30: Insomnia - Part 5
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Some of the first neurological-related discoveries about insomnia were made by placing healthy sleepers or patients with insomnia inside brain scanners, and measuring changes in the activity in different parts of the brain as they tried to fall asleep. In the good sleepers, three main regions of the brain started to shut down at sleep: 1) emotion-related regions, 2) basic alertness-generating regions, and 3) the sensory awareness gate of the brain.

There were also changes in the functional connectivity of large-scale networks in the brain. In patients with insomnia, the functional connectivity between these networks changes differently. Specifically, two large-scale networks show abnormalities in patients with insomnia: the default mode network, associated with ruminating and thinking about the past and future; and the salience network, associated with detecting threats and instigating changes in mood and emotional reactivity. These two areas become overly communicative and too tightly bound up together in their ongoing chatter of connectivity in patients with insomnia. Once again, this can lead to excessive worry, rumination, and emotion and a feeling of being under threat.

Matt has previously mentioned how patients with insomnia can have an excessive release of stress-related chemicals. Those chemicals can also flood the brain, causing excessive activation in all the stress-related regions described above. Critically, though, it’s a reciprocal relationship—if you have hyperactivation in those parts of the brain, you can also trigger the body to release those stress-related chemicals. This becomes a self-fulfilling, negative-spiral prophecy where, as each response increases, further stress-related brain and body activation occurs. 

These measurable changes in the brain and body teach us that insomnia is associated with a specific, and quite complex, set of changes within the brain and the body. No wonder the blunt instruments of old-school sleeping pills are yet to be the ideal way to treat insomnia.

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 one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and 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.

Also sponsoring this week are those fine people at Athletic Greens , and they are generously offering 3 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 because he’s serious about his health, and because he did his research on the science and ingredients in Athletic Greens and thinks its scientific data can be taken as ground truth.

So, make your way over to InsideTracker and Athletic Greens to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Sep 12, 2022
#29: Insomnia - Part 4
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Today’s episode focuses on changes within the bodies of people suffering from insomnia. Almost all forms of chronic insomnia come with a significant psychological component, namely emotional distress and anxiety. This starts a Rolodex of anxiety spinning once you turn off the lights. This leads to rumination and catastrophizing, which will thwart any hopes of a good night’s sleep.

Since psychological stress is one of the principal triggers of chronic primary insomnia, researchers went in search of the underlying biological cause. We found two culprits. 

First was an overactive state of the sympathetic nervous system. Under normal circumstances, it will occasionally switch on in response to a threat, kicking off a cascade response which increases your heart rate, blood flow, and metabolic rate. However, a chronic elevated flight or flight state, as occurs in insomniacs, has damaging biological consequences. A racing heart and raised metabolic rate lead to a raised core body temperature, when exactly the opposite is necessary for good sleep. 

Second was the discovery of an excessive amount of activity in the adrenal cortisol-producing system (called the HPA axis) in insomniacs. When you experience a chronic state of stress, worry, and anxiety, that adrenal stress HPA axis instigates a chain of command response, resulting in the release of the wake-promoting hormone called cortisol. In good healthy sleepers, cortisol levels normally hit their lowest levels right at the point they’re falling asleep.

In insomnia patients, cortisol levels do start falling early in the evening. But then, they spike back up right at the point of bedtime. Later in the middle of the night, we also see cortisol levels once again spike in insomnia patients. These two spikes seem to overlap with the two main flavors of insomnia: sleep-onset and sleep-maintenance. 

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.

Sponsoring today's podcast is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can fully get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. 

Another sponsor of the podcast this week are those fine people at Athletic Greens, and they are generously offering 3 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 because he’s serious about his health, and because he did his research on the science and ingredients in Athletic Greens and thinks its scientific data can be taken as ground truth.

So, make your way over to LMNT andAthletic Greens and take advantage of these incredible deals. As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Aug 29, 2022
#28: Insomnia - Part 3
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Today’s episode takes two questions as its subject: first, why does someone develop insomnia, and second, what adds gasoline to the sleep-disorder fire of insomnia and only makes it rage more powerfully? These are two very complex questions, but through lots of great science and wonderful scientists, we now have a conceptual model explaining how you may find yourself falling into the pit of insomnia. This is called the “3-Ps” model, and it consists of a three-step knock-on cascade of factors that lead to insomnia: predisposing, precipitating, and perpetuating factors.

Predisposing factors are those that make a person more vulnerable to insomnia, a good example being certain types of genes that play a non-trivial role in your risk of developing insomnia. It’s been discovered that insomnia shows a genetic heritability of between 28%-45%, so if one or both of your parents had insomnia, there is a predisposing risk of developing it. This is not, however, an absolute guarantee that you will develop the condition; these genes simply make you statistically more predisposed. Instead, something else has to come along to flick the first domino that causes the chain reaction development of insomnia.

This inciting flick is what the second P—precipitating factors—refers to. The word “precipitate” comes from the Latin root praecipitat, meaning “thrown headlong into something,” which is a good description of what a precipitating factor is—it’s a trigger that pushes you headlong into this thing called an insomnia disorder. Examples of these factors include bereavement, bad breakups, and stress at work, all of which can push someone over the threshold of developing insomnia.

The third P—perpetuating factors—can also be understood through its Latin root, perpetuus, meaning “to continue or make permanent.” Perpetuating factors are those which continue the condition and make it even more permanent. They include examples of poor sleep hygiene like drinking too much caffeine during the day or using alcohol or THC (which is involved in cannabis) as a sedative in the evening. Of course, it’s completely understandable that someone suffering from insomnia would reach for the crutch of alcohol or THC, but they are now understood to be perpetuating factors that only make matters worse.

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.

Today’s podcast is supported by MasterClass - the online streaming platform where anyone can learn from the world's best about a variety of topics such as cooking, business, art, entertainment, writing, sports, science, health, and, of course, technology. When you sign up, you get access to all of the classes taught by such masters as Martin Scorsese, Venus Williams, Gordon Ramsay, Steph Curry, Neil deGrasse Tyson, Timberland, Ron Howard, and Bill Clinton to name just a few of Matt’s favorites. You may even find a masterclass from a familiar sleep scientist! So if you're curious and have a thirst for learning,  head on over to masterclass.com/mattwalker and you will get a discount when you sign up.

So, make your way over toMasterClass to 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.



Aug 15, 2022
#27: Insomnia - Part 2
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There is no quick test that can determine insomnia. Instead, the diagnosis of clinical insomnia disorder is based on a set of clinical assessment and interviews. These center on three core features: 1) difficulties falling asleep, 2) difficulty staying asleep, or 3) waking up and not feeling refreshed by your sleep.  Furthermore, to receive the diagnosis, you often have to be experiencing these things at least three nights per week; and having these issues for three straight months.

One meta-analysis looked at over twenty studies of people with insomnia or healthy sleep. It found far fewer differences in their sleep recordings than you would imagine. The insomnia patients did spend more time awake, and there were reductions in their deep non-REM and REM sleep. But none of the differences  explain the degree of suffering for those with insomnia. 

This mismatch can be illustrated by an extreme example. There is a rare variant or subtype of insomnia called sleep state misperception. It is characterized by a mismatch whereby the patient reports their sleep as very bad. But the sleep recordings show a different story. The recordings show that the patient has slept a full, normal night of sleep, but the patient will tell you that they felt as though they never slept a wink! 

Such patients used to be dismissed as having nothing wrong with them. Now, science and medicine no longer take this view, and instead, understand that there is a mismatch going on, that the patient has a misperception of their sleep, and they still require clinical consideration.

So, that’s an overview of insomnia classification and diagnosis. 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 one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and 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.

Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 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 second, because Matt did his research on the science and ingredients in Athletic Greens and thinks scientific data that can be taken as ground truth.

So, make your way over to InsideTracker and Athletic Greens to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram

Aug 01, 2022
#26: Insomnia - Part 1
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Today’s episode is the first in a 7-part series on insomnia. Matt starts with a calming reality—insomnia isn’t a single bad night or a string of bad nights of sleep. In the US, epidemiological studies have suggested that insomnia disorder is as prevalent as the obesity epidemic: around 10-15% of the population suffer from clinical-grade insomnia, making it the most common sleep disorder. Indeed, one out of every two people will experience insomnia during their lifetime. It is therefore very likely that you or someone close to you is suffering from insomnia.

But what is insomnia? There are perhaps different “flavors” of insomnia, although it depends on the clinical criteria used by different countries. One useful way scientists and doctors have thought about it is on the basis of three different features: 1) sleep-onset insomnia, 2) sleep-maintenance insomnia, and 3) non-restorative sleep. These features are not mutually exclusive.

Clinicians often use the 30/30/3 “rule of thumb” to first distinguish the possibility of insomnia. The 30/30/3 rule means the following: 1) it takes you at least 30 minutes to fall asleep,  or 2) 30 minutes go fall back to sleep after waking during the night, and 3) that this is  happening consistently at least 3 nights a week.

Insomnia is *not* sleep deprivation. Sleep deprivation is  defined as having the sufficient ability to generate sleep, but insufficient opportunity to get it. Insomnia is the opposite of this. Insomnia is the insufficient ability to generate good quality or quantity of sleep, despite having sufficient opportunity time to sleep.

Finally, Matt points out that insomnia can be a standalone condition, or a secondary symptom of something else, for example, chronic back pain.

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.

One of the sponsors of the episode today is a long-time one, our good friends at the athletic clothing company, Vuori. They, too, have a special deal for you all where you can get 20% off your purchase when you visit vuori.com/mattwalker. Vuori produces really good, high quality clothing, and they offset their carbon footprint 100%, both of which, of course, mean a great deal to me. So, if you like athletic clothing, and you wish to help the planet out, then check them out at vuori.com/mattwalker and get 20% off your purchase. 

Another sponsor of today's podcast is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can fully get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. So, if you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase. 

 And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Jul 18, 2022
#25: Optimising Your Sleep
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Today’s episode focuses on optimising your sleep. It’s designed for people who don’t have clinical insomnia but would like to fine-tune their sleep. Matt goes over five conventional tips, and five unconventional tips that may be new to you. 

The first tip is regularity—going to bed and waking up at the same time every day. Your brain has its own master 24-hour clock, the suprachiasmatic nucleus, which expects regularity. 

Second is temperature—your brain and body need to drop their temperature for you to fall and stay asleep, so the ambient temperature must be cold. 

Third is darkness—we need darkness to trigger the release of melatonin. 

Fourth is to walk it out. If it’s been around 25 minutes, and you can’t fall asleep, get out of bed, relax in another room, and come back to bed later. 

Finally, try to abstain from coffee from around noon and avoid drinking alcohol in the evening.

Of the non-conventional tips, the first is this: if you’ve had a bad night’s sleep,  DO NOTHING. Don't wake up any later. Don't drink excessive compensation caffeine. Don't nap. And don't go to bed any earlier the following night. That explains the reasons why.

The second tip is to have a wind-down routine. Your biology needs to wind down so you can descend into good sleep at night, so we should all find our own wind-down routine.

Third is to stay away from naps, especially after 1pm, which is a bit like snacking before your main meal. 

The fourth tip is don’t count sheep. It doesn't work (in fact, it makes matters worse!) Instead, take yourself on a familiar mental walk. Doing this helps take your mind off itself and lets you fall asleep because you stop overthinking.

And the ffinal unconventional tip is to remove or cover all clock faces in the bedroom. 

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 one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and 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.

Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 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 second, because Matt did his research on the science and ingredients in Athletic Greens and thinks scientific data can be taken as ground truth.

So, make your way over to Athletic Greens and InsideTracker to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, p<

Jul 04, 2022
#24: Sleep is Bloody Remarkable - Part 2
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Matt is back this week with his recurring series, ‘Sleep is Bloody Remarkable’. Today’s episode is all about why we are unique when it comes to sleep. 

When we compare our sleep to that of all other primates, humans stand out in two ways. First, we spend far less time asleep, and second, and in bloody remarkable 😂 contrast, humans get more than double the amount of REM sleep.

Unlike many other primates, we humans are exclusively ground (or bed!) sleepers. In contrast, primates usually sleep arboreally, meaning in the branches of trees. During REM sleep, to prevent acting out our dreams, the brain paralyzes the body. But this is far too dangerous to do if you are sleeping up in the trees, lest you fall fatally down to earth.

Homo erectus, as the first obligate biped and, with fire to deter predators and blood-sucking insects, was able to sleep fairly safely on the ground. However, fire didn’t eradicate all the risks. This forced another [bloody] remarkable change: hominids had to become far more efficient in their sleep and thus shorter duration of sleep. 

This re-engineering of human sleep became one of the triggers that rocketed Homo sapiens to the top of the evolutionary pyramid due to REM sleep’s supercharging of 1) our socioemotional, allowing us to form the cooperative societies that formed the basis of modern civilizations, and 2) cognitive intelligence, particularly our creativity, which was the fuel to our brain-derived engine of ingenuity that helped in the great advances of civilization. 

“Simply put: we sleep, therefore, we are.” 

Sleep really is bloody remarkable. 

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.

One of the sponsors of today's podcast is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. So, if you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase.

Another sponsor of the episode today is our good friends at the athletic clothing company,
Vuori. They have a special deal where you can get 20% off your purchase when you visit vuori.com/mattwalker. Vuori produces high quality clothing, and they offset their carbon footprint 100%, both of which, of course, mean a great deal to me. So, if you like athletic clothing, and you wish to help the planet out, then check them out at vuori.com/mattwalker and get 20% off your purchase.   

So, make your way over to LMNT and Vuori to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Jun 20, 2022
#23: Dreams – Part 6
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In this episode, Matt goes deeper into his exploration of  lucid dreaming. He tells us all about studies demonstrating that lucid dreamers can wake from dream sleep on command, demonstrating control over intention in their dreams, and even bring themselves to orgasm in dream sleep!

Matt tells us about two leading methods for developing the skill of lucid dreaming. The first is Mnemonic Induction of Lucid Dreams, which involves the creation of a conscious, deliberate intention to remember that one is dreaming. For example, repeating a certain phrase each night before sleep. The second is the Reality Testing Method. This involves consistently examining one’s environment and testing to differentiate between which of the two worlds, waking or dreaming, it is. The idea is to ingrain these tests in your waking life, so that they will flow over into your dreams, thereby triggering lucidity if you are dreaming.

But how does the brain become lucid during dreaming? It’s been discovered that when lucid dreaming starts, the prefrontal cortex fires up into activity! This seems to be a defining quality of the lucid dreaming state, different to classical REM sleep dreaming where this rational control region of the prefrontal cortex re-engages, thereby letting you gain volitional control over what you dream.

Matt finally poses this hypothesis: between 80 to 90 percent of the populace are not lucid dreamers. If gaining dream control was so beneficial, surely more of us would do it. However, Matt counters his own argument: as we have not stopped evolving, it’s possible that lucid dreamers represent the next iteration of hominid evolution in their ability to control their dreams, and potentially harness their preferred creative problem-solving ability! #mindblown!

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 one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and 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.

Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 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 second, because Matt did his research on the science and ingredients in Athletic Greens and thinks scientific data that can be taken as ground truth.

So, make your way over to InsideTracker and Athletic Greens to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Jun 06, 2022
#22: Dreams - Part 5
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In part five of his series on dreams, Matt discusses what lucid dreaming is and how it was scientifically proven to be real.

We define lucid dreaming as the moment when an individual becomes aware they are dreaming. Historically, the concept of lucid dreaming was considered a scientific scam. First, to claim that people can gain conscious control over a normally unconscious process injects a heavy dose of ludicrous into the already preposterous experience we call dreaming. Second, how could any scientist objectively prove a subjective claim, especially when the individual is asleep when they do it?

Well, several years ago, an experiment removed all such doubt. Lucid dreamers were placed inside an MRI scanner and instructed to alternately clench their hands. The researchers took snapshots of their brains as they were doing this, allowing them to define the precise  areas controlling each individual’s left and right hand. In the second part, the participants again underwent an MRI scan, this time, allowed to enter REM sleep.

Once the subjects became lucid, they signaled their awareness with a specific set of eye movements so researchers could take MRI pictures of brain activity. They then gave another set of eye signals to demonstrate that, in the dream, they were now alternating between clenching their hands.

Each time the dreamers indicated that they were clenching a hand, the scientists were able to take down timestamps. Of course, the participants weren’t physically moving their hands, but amazingly, the results of the MRI scans proved that they weren’t lying; the same regions of the brain that were active during the physical movements lit up when the lucid dreamers clenched in dreams. With these results, the scientists had gained objective proof that lucid dreamers can not only control when they are dreaming but can also control what it is they 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.

One of the sponsors of the episode today is our good friends at the athletic clothing company, Vuori. They have a special deal for you all where you can get 20% off your purchase when you visit vuori.com/mattwalker. Vuori produces high quality clothing, and they offset their carbon footprint 100%, both of which, of course, mean a great deal to me. So, if you like athletic clothing, and you wish to help the planet out, then check them out at vuori.com/mattwalker

Another sponsor of today's podcast is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can fully get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities important to maintaining your blood biochemical balance. So, if you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase.

As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

May 23, 2022
#21: Dreams - Part 4
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Today’s episode focuses on a second but very different function of dreaming: the ingenious processing and interconnection of memories that inspires creativity and even problem-solving ability.

Matt describes how we can think of REM sleep dreaming as a form of informational alchemy, in which we build new connections. As a consequence, we wake the next morning with a mind-wide web of associations capable of divining solutions to previously impenetrable problems.

A great illustration of dream-inspired creativity is the chemist Dmitri Mendeleev, who had been trying for years to solve arguably the greatest problem of his time: how do all of the elements in the universe fit together? When Mendeleev finally lay down to sleep, his dreaming brain came up with the Periodic Table. It’s not just in the sciences that we’ve seen dream-inspired insight. Consider, for example, Sir Paul McCartney’s origination of the songs “Yesterday” and “Let It Be,” both of which came to McCartney in his dreams. 

Matt and his team conducted a study which found that participants were 30% better at solving cognitive problems when they were woken up out of a REM sleep dreaming state. Moreover he found that the way you solve problems is different when you’re coming out of REM sleep dreaming. Matt suggests that this reflects the biological basis of creativity. Importantly, it’s not just that you dream, but once again, what you dream about that seems to matter.

Little wonder then we’re never told to, “stay awake on a problem.” Instead, we’re told to 'sleep on it'. That phrase, or something close to it, seems to exist in most languages that Matt has enquired about, indicating that the problem-solving benefit of dream sleep is universal.

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 one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and 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.

Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 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 second, because Matt did his research on the science and ingredients in Athletic Greens and thinks scientific data that can be taken as ground truth.

So, make your way over to
InsideTracker and Athletic Greens to take advantage of these incredible deals. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

May 09, 2022
#20: Dreams - Part 3
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Matt’s back with part three of his series on the science of dreaming! In this episode, he discusses how he and other scientists have discovered that dreams are not simply an  unintended by-product of REM sleep. Instead, dreams provide at least two essential benefits for human beings.

The first of these functions involves nursing our emotional and mental health and is the focus of this episode. Matt helps us understand that what makes a memory emotional is that, at the time of the experience, we release a visceral, emotional reaction. This wraps itself around the memory and red flags that memory/experience as important, and tags and bonds itself to the information, creating an “emotional memory.” 

Years ago, Matt and his team discovered that it’s not time that heals all wounds. Instead, it is sleep, that helps the brain divorce the emotion from the memory, offering what Matt has described as, “a form of overnight therapy.” Dreaming of these emotional events allows mental-health resolution, keeping our minds safe from the clutches of anxiety and reactive depression.

Earlier work by pioneering researcher Dr. Rosalyn Cartwright addressed the latter condition of depression. Her remarkable work studied the dreams of people showing signs of clinical depression due to difficult emotional experiences. Through her research, Dr. Cartwright found that only those patients who had been dreaming about their painful experiences went on to gain clinical resolution from their depression. 

When it comes to resolving our emotional difficulties it’s not enough to have dreams. Instead, we seem to need to dream of the events themselves to benefit from that emotional therapy. 

Now if you’re not remembering dreams of difficult experiences you’ve been going through, don't worry. If Matt brought you into his sleep center and woke you while you were having REM sleep, your dream reports would most likely reflect that you are doing exactly what you need to be doing in terms of your emotional processing.

In other words, all of this work tells us that one of the functions of dreaming is to serve as a set of emotional windscreen wipers! As a result when we wake the next morning after a night of dreaming, we are dressed in a very different set of psychological clothing to that we went to sleep in--a less ruffled emotional outfit, free of the sharp creases of painful emotions.

What Matt and his team discovered is that it’s not time that heals all wounds, but rather, it is time spent in dream sleep that provides emotional convalescence. 

To sleep, perchance, to heal.

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 25% off any one of their programs for anyone who uses 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.

Apr 25, 2022
#19: Dreams - Part 2
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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.

Apr 11, 2022
#18: Dreams - Part 1
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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.

Mar 28, 2022
#17: Sleep is Bloody Remarkable - Part 1
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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.

Mar 14, 2022
#16: Sleep & Weight Gain – Part 2
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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.

Feb 28, 2022
#15: Sleep & Weight Gain – Part 1
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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

Feb 14, 2022
#14: Temperature – Part 2
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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.


Jan 31, 2022
#13: Temperature - Part 1
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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.

Jan 17, 2022
#12: Melatonin
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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.

Jan 03, 2022
#11: Sleep & Caffeine – Part 2
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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.

Dec 20, 2021
#10: Sleep & Caffeine – Part 1
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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.


Dec 06, 2021
#09: Sleep & Alcohol - Part 2
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On last week’s episode, we learned about the three main ways alcohol can harm our sleep: 1) alcohol results in sedation rather than naturalistic sleep, 2) alcohol causes sleep fragmentation, and 3) alcohol impairs REM sleep. 

Today, Matt dives into each of these negative impacts, explaining exactly how and why alcohol disrupts our sleep in these specific ways.

First, alcohol is a class of chemicals called “the sedatives,” and sedation is not natural sleep. Healthy sleep is a very active, highly coordinated event within the brain, unlike sedation. As a result, alcohol can result in you waking up and feeling unrestored and unrefreshed by that non-normal sleep. 

Second, we normally need to shut off our fight-or-flight branch of the nervous system, called the sympathetic nervous system, and shift over to the calming, parasympathetic nervous system, in order to stay asleep soundly across the night. However, alcohol reactivates the fight-or-flight nervous system, forcing the brain and body back into a more hyper-alert state. 

This increases the chances of you waking up and staying awake, causing your sleep to become more fragile and prone to fragmented awakenings throughout the night. Alcohol also triggers the release of several stress-related chemicals, including cortisol. This stimulates the fight-or-flight nervous system and emotional centers in the brain, also making it more likely that you will wake up and stay awake.

Finally, alcohol significantly reduces the amount of REM sleep the brain can produce. Specifically, the metabolic byproducts of alcohol degradation within the body disrupts and impairs the generation of REM sleep. Without that REM sleep, we can suffer impairments to our cognitive brain function and emotional stability. We can also experience a heightened amount of negative moods, such as anxiety. REM sleep is also the time when we hit our peak in the release of important hormones, like testosterone, which is critical for both men and women.

While Matt acknowledges that this news may not be especially encouraging or popular, he closes out today’s show with a reminder that life is to be lived. It is not his intention to tell anyone how to live their life. Instead, Matt’s goal is to simply lay out the scientific evidence regarding the relationship between sleep and alcohol, so that you can make an informed decision about how to best structure your own sleep schedule and find an enjoyable life balance.

Please note that Matt is not a medical doctor and none of the content in this podcast should be considered as 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 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.

Nov 22, 2021
#08: Sleep & Alcohol - Part 1
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Although some people may believe that a drink or two in the evening will help them sleep better, today’s episode shows us that alcohol harms our sleep in several different ways. In the first of two episodes on sleep and alcohol, Matt talks about alcohol as a chemical, and the main ways it negatively affects our sleep.

Alcohol has a sedative effect that switches off brain cell firing as we sleep. Alcohol also fragments our sleep, making it less restorative, and blocks REM sleep, which is critical for numerous aspects of health and wellness, including learning and memory, creativity, rebalancing moods and emotions, recalibrating certain hormone systems, and even lifespan longevity.

Matt describes the clock-counter system our brains use to track lost REM sleep, and why we sometimes experience strong, intense and vivid dreams in the late hours of our sleep after too much alcohol as a result. 

In today’s episode, you’ll also learn about the specific ways in which alcohol interferes with our sleep quality, and the different stages of our sleep, REM sleep especially. 

Be sure to tune in next week as Matt further examines exactly what it is about alcohol that disrupts our sleep in these particular ways, and what the consequences are on health and wellness.

Please note that Matt is not a medical doctor and none of the content in this podcast should be considered as 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 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.



Nov 08, 2021
#07: Naps
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As the great Roman poet, Ovid, once said, “There is more refreshment and stimulation in a nap, even of the briefest, than all the alcohol ever distilled.” But are naps always a good thing? Are we even designed to nap? And if you do nap, when should you do it, and for how long? 

Today Matt explores the benefits and pitfalls of napping, how napping may fall in line with our pre-programmed sleep patterns as humans (a natural drop in alertness between 1 and 4pm each day), and what it means if you find yourself waking up from an accidental nap on the couch right before bed. 

You’ll also hear about the NASA nap culture, sleep inertia (which can include a feeling of a “sleep hangover”), and Matt’s advice for how to use naps to your advantage. If done correctly, for most people not struggling with sleep or insomnia, naps can improve alertness, task performance, creativity, and even reduce blood pressure. However, there is a dark side to napping that Matt discusses in detail, and why that can be the case. So join Matt as he walks you through both the advantages and disadvantages of napping!

Please note that Matt is not a medical doctor and none of the content in this podcast should be considered as 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 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.

Detailed Scientific Literature

Naps and overview (by the amazing Prof. Christopher Barnes)

The good and the bad of naps

Naps and Mortality

Naps, Brain function & Performance

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Oct 25, 2021
#06: Chronotype: Part 3
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In the final episode of our three-part series about chronotypes, Matt examines the question of  whether your chronotype is truly fixed, or if you can change an evening type to a morning type (though you will hear that Matt’s preference is for society to change, not the individual). 

Matt reviews a fascinating study by an Australian-lead research team that tried to turn night owls into morning larks. Participants had to follow a series of strict rules over the course of a three-week study. This included things such as: setting an alarm to wake up two to three hours earlier than their normal wake time, eating breakfast first thing after waking up, getting outside for as much natural daylight as possible, and not having any caffeine after 3pm. 

As you’ll hear from Matt, the experiment was...somewhat successful. By the end of the study, evening types went to bed about two hours earlier than usual, managing to get to be around 12:30am, instead of 2:30am. In addition, their performance on several standardized cognitive tasks also improved expressly during the morning hours, when night owls typically struggle the most. 

However, as Matt points out, participants were still opting to go to bed after midnight, which is far from morning night-owl-like, and far from being turned into a morning type. It is also unlikely these individuals could continue with this rigid new set of experimental guidelines across the long-term, for their entire lifespans.

In other words, the results are fascinating, but the practice itself may not be sustainable in the real world. Instead, Matt's wish is that we simply allow evening types to sleep in harmony with their genetic chronotype. If night owls were able to sleep and wake up when they are biologically designed to, the world would be a happier, healthier place indeed.

Please note that Matt is not a medical doctor and none of the content in this podcast should be considered as 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 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.


Basic Resources 

Discover your chronotype: AutoMEQ: Automated Morningness-Eveningness Questionnaire (AutoMEQ)

Scientific Review: Biological Rhythm and Chronotype

Oct 11, 2021
#05: Chronotype: Part 2
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In the second episode of our three-part series on chronotypes,  Matt speaks about what happens when you do not sleep in harmony with your natural chronotype. Unlike morning larks, night owls simply cannot fall asleep easily early at night, which leads to the first and most obvious consequence of not sleeping in line with your chronotype—you don’t sleep as much.

Matt explains that morning types sleep over 7-hours per night on average, while evening types can only manage 6.6-hours of sleep per night. Matt also notes the upshot, which is a chronic “sleep debt”, one that accrues night after night, month after month. The ramifications are many, including increased caffeine intake for evening types, higher likelihood of developing hypertension and Type II Diabetes, and greater difficulty maintaining a healthy body weight. In addition to these consequences to the body, evening types are two to three times more likely to develop depression than their morning type counterparts, and twice as likely to be using antidepressants. 

Matt clarifies that his intent in sharing the concerning statistics is not to worry evening types, but rather, to help them realize their true biological nature, and as important, not feel guilty for it. Today’s episode aims to vindicate and empower evening types with the knowledge that they may be sleep deprived, and to help them find a schedule that falls in line with their natural chronotype.

Matt Finally speaks about current societal practices that push (actually, force) night owls into unhealthy sleep rhythms. He outlines his (lofty 😊) goal of restructuring the typical schedule of work in first-world nations, which is strongly biased toward early start times that incorrectly punish night owls and favor morning larks. Matt notes that this is markedly unfair, since it is not their choice as to which ‘type’ they are. Instead, it is their pre-ordained, genetic-based sleep chronotype, yet society wrongly assumes that evening types could get up earlier if only they weren’t so slovenly. Of course, the science and this episode tells us otherwise.

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 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.

Basic Resources 

Discover your chronotype: AutoMEQ: Automated Morningness-Eveningness Questionnaire (AutoMEQ)

Scientific Review: Biological Rhythm and Chronotype

Scientific Review: Chronotype and Mental Health: Recent Advances

Sep 27, 2021
#04: Chronotype: Part 1
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Episode 04: Chronotype: Part 1

Summary

Are you a morning type? Or are you an evening type? Perhaps you are neither of the two? Today’s episode is the first in a three-part series all about your chronotype, or your body’s natural biological preference to be awake and be asleep at a certain time. 

Matt begins by explaining exactly what your chronotype is, then breaks down the three main “flavors” of chronotype (morning lark, night owl, or somewhere in-between). In addition, and listed in the show notes, below, he explains how to determine whether you are a night owl or a morning lark. 

He will also describe how an individual’s sex falls into the equation and the difference between your chronotype and your circadian rhythm. 

You’ll hear about the key ways in which evening types biologically differ from morning types, that your chronotype isn’t your own choice nor is it your own fault, but rather, there is a very strong genetic basis of why and how you are programmed in terms of being a morning or an evening type? 

Today’s main takeaway is that when you or when society tries to force you to sleep in opposition to your biology, there can be unfortunate consequences. Stay tuned as we explore these in greater detail next time.

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 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.

Basic Resources 

Discover your chronotype: AutoMEQ: Automated Morningness-Eveningness Questionnaire (AutoMEQ)

Scientific Review: Biological Rhythm and Chronotype

Scientific Review: Chronotype and Mental Health: Recent Advances

Sep 13, 2021
#03: Circadian Rhythms
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#03 Circadian Rhythms

Continuing on from last week’s episode about sleep pressure, today, Matt Walker dives into the second half of the sleep-wake story, circadian rhythm. 

Matt explains that your circadian rhythm, or your 24-hour internal clock, begins drumming out its loud activating beat just before you wake in the morning and gets louder throughout the day, peaking in the early afternoon and hitting its lowest point in the middle of your sleep phase overnight. 

Matt describes how circadian rhythm and sleep pressure work independently of one another, yet coincide with a beautiful synchronicity to naturally and gently rouse you from sleep in the morning and rouse you into full wakefulness, then pull you into a wonderful, restorative sleep at night. 

You’ll also hear about the reliable mid-afternoon drop in alertness we see each day, what this means in terms of how humans were designed to sleep, and why it may explain the occasional need for a siesta.

_________________

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  www.athleticgreens.com/mattwalker and get a free year supply of Vitamin D and 5 free travel packs today.

Finally, if you have thoughts on sleep topics that you want Matt to cover, or you have feedback you’d like to share so he can be better at podcasting, please reach out to Matt on Instagram @drmattwalker. He'd love to hear from you🤗!

Aug 26, 2021
#02: Sleep Pressure
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Episode 02:  Sleep Pressure

Welcome back to the Matt Walker podcast. Today’s episode looks at the story of sleep pressure - how it works, how you can try to block it or fool it, and why you feel so good after a night of full, peaceful sleep. 

Matt explains that from the moment you wake up, a chemical called adenosine begins to build up in your body. The longer you’re awake, the more adenosine will build up and the sleepier you will feel. This is called sleep pressure. Once adenosine concentrations peak, usually after about 12-16 hours of being awake, the irresistible urge for slumber takes hold. 

Sleep then purges the buildup of adenosine in your brain, and you will wake feeling refreshed and ready to face another day.

Today, you’ll learn about the dual-action effect of adenosine, how caffeine operates to artificially mute its “sleepiness” signals to the brain, and the ideal length of sleep you need to fully clear the adenosine levels from your body overnight. 

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. Matt is more than a little obsessed with Athletic Greens. He's been using Athletic Greens, each day for the past 3 years (and he does buy his own to prevent any conflict of interest, as that's important to integrity).

Why does Matt use it each day.? 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  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.


Music credit:

By the incredible, Kai Engel (aka Anton Fedchenkov).



Aug 16, 2021
#01: What is Sleep?
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Episode 01:  Highlights

  • Human sleep has been separated into two main types: Non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep
  • NREM sleep is further divided into four stages, with each stage increasing in their depth of sleep
  • REM sleep is named this way because of the bizarre, horizontal, shuttling eye movements that occur underneath your eyelids during this stage of sleep
  • REM sleep is the principal stage in which we dream, although it can occur in the other stages as well
  • NREM and REM sleep play out in a battle for brain domination throughout the night
  • This cerebral war is going to be won and lost every 90 minutes, creating the standard cycling architecture of sleep for humans
  • Other species may have a slightly different NREM to REM cycles, with birds experiencing a cycle that only lasts about 4-5 minutes, and giraffes about 24 minutes
  • During NREM sleep, we see bursts of deeply powerful brain waves that flow over your cortex
  • We also see sleep spindles, which are short, synchronous bursts of electrical brain wave activity that last for about 1-1.5 seconds
  • About 60-70 minutes into your first sleep cycle, your brain starts to rise up again into later stages of NREM sleep, then pop into a short REM sleep period, back to NREM sleep, then returning to REM sleep once again
  • Your brain goes through this cycle every 90 minutes
  • What changes is the ratio of NREM to REM sleep as you move through the night, with your sleep cycle comprised of more REM sleep during the second half of the night
  • If you wake up two hours earlier than usual, you aren’t just losing 2 hours of sleep - you could be losing 50, 60, or even 70% of your REM sleep
  • All stages of sleep are critical and perform different functions for the brain and body at different times of night

Episode Sponsor:
This episode is sponsored by 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 www.athleticgreens.com/mattwalker and get a free year supply of Vitamin D and 5 free travel packs today.

Feedback:
Please visit Matt on Instagram and tell him what he can be doing to make these podcasts better, and let him know what topics you want him to cover next! 

Links:
Brain Basics: Understanding Sleep | National Institute of Neurological Disorders and Stroke

Music credit:
By the incredible, Kai Engel (aka Anton Fedchenkov).



Aug 02, 2021
Trailer & Welcome!
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The Matt Walker Podcast is all about sleep, the brain, and the body  ·  Matt is 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. 

Jul 26, 2021