Welcome to the Huberman Lab Podcast! I’m Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford, but it is part of my desire to bring zero cost consumer information about science and science-related tools. We would like to thank the sponsors of today’s podcast, starting with Helix Sleep. Helix Sleep makes mattresses that are ideally suited to your sleep needs. I can vouch for the quality of their mattresses, as I’ve been sleeping on one and it’s been the best sleep I’ve ever had. What’s great about Helix mattresses is that they are tailored to your unique body type and sleeping style.

Sleeping style is an important factor to consider when choosing a mattress. Helix has a quick quiz on their website that takes about two minutes to complete. It will ask about your preferred sleeping position (stomach, side, back, etc.), whether or not you flip back and forth, and if you tend to run hot or cold. Based on your answers, it will match you with the perfect mattress for your sleep needs. If you decide to try a Helix mattress, you can get $200 off your order and two free pillows by going to helixsleep.com/huberman.

The second sponsor of today’s podcast is Athletic Greens. Athletic Greens is an all-in-one vitamin mineral probiotic drink that I’ve been using since 2012. It was created to help simplify the confusion of what vitamins and minerals to take. It provides everything you need in one easy to consume formula.

I mix Athletic Greens with water and a little bit of lemon juice, and I like drinking it. The probiotics in the mix are important to me, as there is a lot of data out there now identifying the gut microbiome and the importance of the gut-brain axis for immune function, metabolic function and so forth. If you want to try Athletic Greens, you can go to athleticgreens.com/huberman and get a year supply of liquid vitamin D3 and K2. There is a lot of data starting to surface about the importance of vitamin D3 for immune function, metabolic function, endocrine function, and so forth. In addition, if you go to athleticgreens.com/huberman, you’ll also get five free travel packs – little packets of Athletic Greens – which are great for when you’re on the plane or otherwise travelling. These packets mix up easily without any mess or the need to spoon out powder. So, things that are easy to do at home are harder on the road, but these packets make it easy while travelling.

Today we’re going to talk about dreaming, learning during dreaming, and unlearning during dreaming, in particular unlearning of troubling emotional events. Now, my interest in dreaming goes way back. When I was a child I had a friend who came over one day and he brought with him a mask that had a little red light in the corner. He had purchased this thing through some magazine ad that he had seen, and this mask was supposed to trigger lucid dreaming. Lucid dreaming is the experience of dreaming during sleep, but being aware that one is dreaming, and in some cases being able to direct one’s dream activities. For example, if you’re in a lucid dream and you want to fly, some people report being able to initiate that experience of flying, or to contort themselves into an animal, or to transport themselves to wherever they want within the dream. I tried this device.

The way it worked is you put on the mask during a waking state, when I was wide awake, and you look at the little light flashing in the corner. You would also wear it when you went to sleep at night. I could see the red light presumably through my eyelids, although I may have opened my eyes – I don’t know, as I was asleep. Whilst dreaming, I was able to recognize that I was dreaming and then start to direct some of the events within that dream. Lucid dreaming occurs in about 20% of people, and in a small percentage of those people they lucid dream almost every night, to the point that their sleep is not as restorative as it would otherwise be. Lucid dreaming and dreaming in general are profound experiences, and we tend to feel extremely attached to our dream experience. This may explain why people feel the need to tell everybody about their intense dream.

Dreaming often occurs during the REM (Rapid Eye Movement) stage of sleep. Numerous people throughout history have tried to make sense of dreams in some sort of organized way, the most famous of which of course is Sigmund Freud who talked about symbolic representations in dreams. Although much of Freud’s theories have been debunked, there is still some interest in what the symbols of dreaming are. To better understand dreams and how to maximize the dream experience for the sake of learning and unlearning, it is important to look at the physiology of sleep. As we get sleepy, we tend to shut our eyes due to autonomic centers in the brain that control the closing of the eyelids. Sleep is generally broken up into a series of 90 minute cycles, and dreaming often occurs during the REM stage.

We tend to have ultradian cycles during the night of sleep. Early in the night, these 90 minute cycles tend to be comprised more of shallow sleep and slow wave sleep. This includes stage one, two, etc. and slow wave sleep. Later in the night, there is more rapid eye movement (REM) sleep and less slow wave sleep. This is true even if the sleep is broken up by having to use the restroom. I will go into more detail about what all this means in a moment.

Slow wave sleep (SWS) and non-rapid eye movement (NREM) sleep have distinctly different roles in learning and unlearning. SWS and NREM are responsible for learning and unlearning different types of information, which has implications for motor skills, traumatic events, emotionally challenging and pleasing events. We can leverage our daytime activities to access more SWS or NREM, or more rapid eye movement (REM) sleep depending on our needs. We’ll also discuss lucid dreaming, hallucinations, and how drug-induced hallucinations have similarities and differences to dream states.

To start, let’s discuss SWS and NREM. We can have more control and power over this stage of life than we might believe. Understanding the differences between SWS and NREM can help us better understand how to access more of the sleep we need.

Slow wave sleep is characterized by a particular pattern of brain activity in which the brain is metabolically active with big sweeping waves of activity that include a lot of the brain. This includes sweeping of waves of neural activity across association cortex, the brainstem, thalamus, and cortex. When I refer to slow wave sleep, I generally mean non REM sleep although I acknowledge there is a distinction.

Slow wave sleep is associated with the neuromodulators acetylcholine, norepinephrine, serotonin, and dopamine. These chemicals act slowly but their main role is to bias particular brain circuits to be active and other brain circuits to not be active. It is similar to the way a music playlist suggests particular genres of neural circuit activity, such as classical music versus third wave punk or hip hop. These neuromodulators are associated with certain brain functions, and slow wave sleep is one of them.

Acetylcholine is a neuromodulator that tends to amplify the activity of brain circuits associated with focus and attention. Norepinephrine is a neuromodulator that tends to amplify the brain circuits associated with alertness and the desire to move. Serotonin is the neuromodulator that’s released to amplify the circuits in the brain and body that are associated with bliss and the desire to remain still. Dopamine is the neuromodulator that’s released and is associated with amplification of the neural circuits in the brain and body associated with pursuing goals, pleasure, and reward.

In slow wave sleep something interesting happens. Acetylcholine production and release and action from the two major sites, which are the parabigerminal nucleus in the brainstem and the nucleus basalis in the forebrain, plummets. This is why acetylcholine production is so low during slow wave sleep.

Slow wave sleep is associated with focus, and is characterized by big sweeping waves of activity through the brain. During this stage, the molecules acetylcholine and norepinephrine are present, though in small amounts. Norepinephrine is normally associated with alertness and the desire to move, but in slow wave sleep it is not as prominent. Serotonin, however, is present in large amounts and is associated with a sensation of bliss or wellbeing. Slow wave sleep typically occurs at the beginning of the night and is characterized by a lack of movement.

During sleep, people tend not to move. However, during slow wave sleep they can move, allowing them to roll over or sleepwalk. Studies have shown that when people are deprived of slow wave sleep, or when their sleep is chemically altered to bias them away from slow wave sleep, motor learning is generally impaired. For example, if someone has learned a new dance move or motor skill the day before, such as a new form of exercise or a new coordinated movement involving either their fingers or their whole body, their ability to remember and perform the skill may be affected.

Slow wave sleep has been shown to be important for the learning of detailed information. This includes cognitive information, such as learning very specific rules and the way certain words are spelled. Studies have shown that people deprived of slow wave sleep tend to perform poorly on tests that involve these types of information. Motor learning, motor skill learning, and the learning of specific details about specific events also occur during slow wave sleep, primarily in the early part of the night. Therefore, those who only get three or four hours of sleep may not be able to learn as much as they would if they had more sleep.

We are going to dive deep into how to maximize motor learning in order to extract more detailed information about coordinated movements and how to make them faster or slower. This is important for certain sports as well as any kind of coordinated movement, such as learning to play the piano or learning synchronized movements with somebody else. As an example, I set out to learn tango a few years ago due to some Argentine relatives, but as a bismal, it was difficult as someone else had to suffer the consequences as well. I may explore this again as a self-experimentation in the month on neuroplasticity.

Slow wave sleep is involved in motor learning and detailed learning. It has big amplitude activity sweeping throughout the brain, and the release of neuromodulators such as norepinephrine and serotonin. This happens early in the night, so athletes and people concerned with performance should be fine to engage in activities after just a few hours of sleep. However, it is always better to get a full night’s sleep, which is usually 6 hours. If you have already learned what you need to do and it is stored in your neural circuits, the literature on slow wave sleep suggests that your motor learning and recovery from exercise will be replenished.

REM sleep occurs throughout the night, with a larger percentage of the 90 minute sleep cycles comprised of REM sleep as you get toward morning. REM sleep was discovered in the 1950s when researchers at a sleep laboratory in Chicago observed that people’s eyes were moving under their eyelids. The eye movements are not just side to side, they are erratic in all different directions. One thing that is not often discussed is why eye movements occur during sleep, when the eyes are closed. Sometimes people’s eyelids will be a little bit open and their eyes are darting around, especially in little kids.

Although I don’t suggest you do it, it has been done before to observe rapid eye movement (REM) sleep. This occurs because of connections between the brainstem, pons, thalamus, and top of the brain stem that generate movements in different directions. During REM sleep, the circuitry involved in conscious eye movements is activated, resulting in a jittery side to side movement and rolling of the eyeballs. This is caused by waves of activity that travel from the brainstem up to the thalamus and then to the cortex. It is a fascinating phenomenon to observe, but it can also be quite creepy.

The cortex of course is involved in conscious perceptions. In contrast to slow wave sleep, during rapid eye movement (REM) sleep, serotonin, which tends to create the feeling of bliss and wellbeing, is essentially absent. In addition, norepinephrine, which is involved in movement and alertness, is also absent. This is probably one of the few times in our life that epinephrine is at zero activity within our system.

This has important implications for the sorts of learning and unlearning that can occur during REM sleep.

REM sleep has a number of very important implications for the sorts of dreaming and learning that occur during this state. We are completely paralyzed, experiencing what is known as atonia, and we tend to experience whatever we are dreaming about as a kind of hallucination. Long ago, I became interested in this topic and there are some great books on the relationship between hallucinations and dreaming. Alan Hobson’s book, Dream Drug Store, talks about the similarities between drugs that induce hallucinations and dreaming in REM. During REM, our eyes are moving, but the rest of our body is paralyzed and we are hallucinating. This has important implications for the sorts of learning and unlearning that can occur during REM sleep.

Epinephrine doesn’t just create a desire to move and alertness; it is also the chemical signature of fear and anxiety. It is released from our adrenal glands when we experience something that is fearful or alerting, like a car screeching in front of us or a troubling text message. Adrenaline and epinephrine are equivalent molecules, and epinephrine is also released within our brain. During REM sleep, a stage of life that happens more toward morning, we hallucinate and have outrageous experiences in our mind, but the chemical associated with fear and panic and anxiety is not available to us. This lack of epinephrine is very important, and it is easy to understand why.

Dreaming is an important part of sleep that allows us to experience things without fear and anxiety. It helps us adjust our emotional relationship to challenging things that happened while we were awake. People often report dreams where they find themselves in troubling situations such as being late to an exam, naked in public, etc. These dreams likely occur during REM sleep, where our experience of emotionally laden events is dissociated from the actual emotion. Nightmares, however, may occur during slow wave sleep. There are drugs that can help with nightmares, but they are not recommended.

In fact, many people have had dreams that give them a very scary or eerie feeling, such as feeling like they are being chased and can’t move. This is a common dream, and is more or less a nightmare. The feeling of being paralyzed and chased is often attributed to REM sleep, but research suggests that this occurs in slow wave sleep instead, as there is no epinephrine present during REM sleep.

Although there may be instances where people have nightmares in REM sleep, some people also experience feeling very stressed upon waking up, due to whatever it was that they were thinking or dreaming about in the moments before.

Nightmares very likely in slow wave sleep and that kind of panic on waking from something very likely to be an invasion of the thoughts and ideas, however distorted, in REM sleep invading the waking state. Many people report the experience of waking up and being paralyzed. They are legitimately waking up, it is not a dream. This is terrifying and can be caused by the atonia, or paralysis, that we experience during sleep invading the waking state. Research on this is not yet fully crystallized, but most of it points in the direction of the experience of waking up and feeling very panicked. This may be because the brain circuits associated with fear and anxiety are shut off, so the experience of something troubling during the day is repeated in the sleep state, but without epinephrine available to shut off these circuits. However, when we wake up, the surge of epinephrine is coupled to that experience, making the experience even more intense and panic-inducing.

It is terrifying to be wide awake and fully conscious, yet unable to move. Generally, one can jolt themselves out of this state in a few seconds, but it is still quite frightening. Some people report experiencing waking up, being paralyzed, and hallucinating; these core characteristics are very similar to what people report as alien abductions. People often report being unable to move, seeing particular faces, feeling their body floating, or being transported. This is similar to the experience of atonia into the waking state, and the hallucinations associated with dreaming and REM sleep. It is possible that people are experiencing these things and it can last several minutes or longer. I cannot say whether these are legitimate alien abductions or not, as I was not there; however, it is possible.

Slow Wave Sleep (SWS) occurs early in the night and is important for motor and detailed learning. Rapid Eye Movement (REM) sleep has a dream component in which epinephrine is not present, leading to an absence of anxiety and paralysis. Dreams in REM sleep tend to be vivid and contain a lot of detail. The type of learning that occurs in REM sleep is not motor events, but rather unlearning of emotional events. This is due to the lack of chemicals available to really feel those emotions.

Now that has very important implications. So let’s address those implications from two sides. First of all we should ask, what happens if we don’t get enough REM sleep?

A scenario that happens a lot where people don’t get enough REM sleep is the following: I go to sleep around 10:30, 11:00, I fall asleep very easily and then I wake up around 3:00 or 4:00 AM.

I now know to use a NSDR, a non sleep deep rest protocol and that allows me to fall back asleep. Even though it’s called non sleep depressed it’s really allows me to relax my body and brain, and I tend to fall back asleep and sleep till about 7:00 AM.

During which time I get a lot of REM sleep. And I know this because I’ve measured it, and I know this because my dreams tend to be very intense of the sort that we know is typical of REM sleep.

I have gotten my slow wave sleep early in the night and my REM sleep toward morning. However, there are times when I don’t go back to sleep, such as when I have a flight to catch or when I have a lot on my mind. The lack of REM sleep tends to make people emotionally irritable and causes us to feel as if the little things are the big things. Laboratory studies have shown that when people are deprived of REM sleep, their emotionality becomes unhinged and they tend to catastrophize small things, feeling like they will never move forward.

REM sleep also plays a role in the replay of spatial information about where we were and why we were in those places. This maps to data and studies initiated by Matt Wilson at MIT years ago. We cannot unlearn the emotional components of whatever it is that has been happening, even if it’s not traumatic.

Showing that in rodents, other non-human primates, and humans, there is a replay of spatial information during Rapid Eye Movement (REM) sleep. This replay almost precisely maps to the activity experienced during the day as we move from one place to another. For example, when navigating a new place, such as a city, a building, or finding particular rooms, or experiencing new social interactions, if it is important enough, it becomes solidified a few days later and is not forgotten. During REM sleep, there is a literal replay of the exact firing of the neurons that occurred while navigating the same place. This suggests that REM sleep is involved in the generation of detailed spatial information. Additionally, during REM sleep, there is an uncoupling of emotion, and we are forming a relationship with particular rules or algorithms.

We’re starting to figure out, based on all the experience that we had during the day, whether or not it’s important that we avoid certain people or approach certain people, or that we enter a building and go into the elevator and turn left where the bathroom is, for instance. This process of piecing together the relevance of one thing to the next is called meaning. During our day we experience all sorts of things and it is during REM sleep that our brains solidify these relationships and make sure that certain relationships don’t exist. When people are deprived of REM sleep, they start to see odd associations and lump or batch things. This is something I know from my own experience when I have been sleep deprived and pull an all-nighter; words start to look like they are spelled incorrectly.

The word “and” is a very simple one to spell, but things start to look distorted when people are deprived of REM sleep for long periods of time. This can lead to hallucinations, where people start to see relationships and movement of objects that aren’t actually happening. REM sleep is where we establish the emotional load and discard the meanings that are irrelevant. This is important in order to have healthy emotional and cognitive functioning, as it requires us to have narrow channels between individual things. If we are troubled by everything and feel highly irritable, this could be a sign of a deficit in REM sleep, as it has the power to eliminate the meanings that don’t matter.

REM sleep is not just a time when we dream, but it also eliminates the meanings that don’t matter. Much like what happens early in development, children cannot generate coordinated movements or place events into a larger context because they have too much connectivity. Maturation of the brain and nervous system is about elimination of connections between things, which is why REM sleep is so important. This is similar to clinical practices such as EMDR and ketamine treatment for trauma, which aim to help people move through trauma and other troubling experiences.

EMDR, or Eye Movement Desensitization and Reprocessing, was developed by psychologist Francine Shapiro in Palo Alto. She was walking in the trees and forest behind Stanford when she recalled a troubling event from her own life. She noticed that the emotional load of the experience was not as intense or severe. She then began to use this practice with her clients and patients, and it has now become widespread. It is one of the few behavior treatments approved by the American Psychological Association for the treatment of trauma.

During EMDR sessions, clients and patients move their eyes from side to side while recounting a traumatic or troubling event. This practice takes place in the clinic.

My friend went to the clinic to take part in an eye movement therapy component. This was done instead of the walking component as it would be difficult to discuss confidential matters with people around and weather barriers such as rain or hail. She never said why eye movements were chosen, but soon I will explain why this was the right decision. These eye movements involve sitting in a chair and moving one’s eyes from side to side, not while talking, and then recounting the events. They may look silly, but they are effective.

When people are engaging in EMDR, they are engaging in a type of therapy that involves moving the eyes from side to side for 30-60 seconds. As a vision scientist and someone who works with stress, I initially thought this was crazy. Upon further research, I found that there were several theories as to why EMDR might work. One theory was that it mimics the eye movements during REM sleep, but this was later found to be untrue. Another theory was that it synchronizes the activity on the two sides of the brain, however modern neuroscience is starting to move away from this concept of right brain and left brain.

Eye movements, such as those used in EMDR, are generated whenever someone is self-generating movement. This includes activities such as walking, running, and riding a bicycle. These reflexive subconscious eye movements are associated with the motor system.

EMDR has been shown to suppress the activity of the amygdala, helping people move through or dissociate the emotional experience of particular traumas. Studies have reported success rates that are statistically significant, and in the last five years there have been no fewer than five high quality peer reviewed manuscripts published in various journals. These studies have shown that lateralized eye movements, moving the eyes from side to side with eyes open, suppress the activity of the amygdala, which is involved in threat detection, stress, anxiety, and fear.

We’ve got a clinical tool now that shows a lot of success in a good number of people. This tool uses eye movements from side to side to suppress the fear response. After the fear is suppressed, the person recounts or repeats the experience, and over time the emotional load (sadness, depression, anxiety, fear) is uncoupled from the traumatic experience. It is important to note that the experience is never forgotten, rather, the emotional potency is alleviated. EMDR tends to be most successful for single event or very specific kinds of trauma, such as car crashes, rather than an entire childhood or divorce. It should be done in a clinical setting with somebody who is certified to do this.

The experience of REM sleep bears a lot of resemblance to the fear response generated by the chemical epinephrine. During REM sleep, we remember events from the previous day or days and sometimes even events from a long time ago. Recently, a new treatment using the drug ketamine has been gaining attention. Ketamine is a dissociative anesthetic, similar to the hazardous drug PCP. Both ketamine and PCP disrupt the activity of the NMDA receptor in the brain.

The NMDA receptor is a receptor found on the surface of neurons, which is typically not active. However, when an intense event occurs in the neural pathway, the receptor opens and allows molecules and ions to enter, triggering a cellular process called long-term potentiation. This change in connectivity means that later, the neuron does not need the intense event to become active again.

To clarify, the NMDA receptor is gated by intense experience. For example, if someone were to come home one night, sit down to a bowl of chicken soup, and then experience a massive explosion, the neurons associated with the chicken soup and kitchen table would be activated in a way that was different than before. The next time they go to sit down at the kitchen table, they would have the same experience, even if they are rational about the origins of the explosion.

Ketamine blocks the NMDA receptor and prevents the crossover of meaning to the chicken soup-explosion experience. This is how ketamine is being used.

Ketamine is being used to prevent learning of emotions very soon after trauma. It is being stocked in a number of different emergency rooms, where if people are brought in quickly after a traumatic experience, such as seeing a loved one killed in a car accident, they may be infused with ketamine so that their emotion can still occur, but the plasticity of their brain won’t allow the intense emotion to be attached to the experience. This has ethical implications, as certain emotions need to be coupled to experiences. It should not be used recreationally, as it can be lethal and can cause dramatic changes in perception and behavior. In a clinical setting, the basis of ketamine assisted therapies is to remove emotion. It should not be confused with psilocybin or NMDA trials, which are about becoming more emotional or getting in touch with a certain experience; ketamine is about becoming dissociative or removed from the emotional component of experience.

We have three pharmacologic and therapeutic interventions that are designed to suppress the amygdala and remove emotionality while someone recounts an experience. Ketamine chemically blocks plasticity and prevents the connection between an emotion and an experience. EMDR is a type of eye movement that is designed to suppress the amygdala. Lastly, REM sleep is a component of our sleeping life that acts like therapy. Epinephrine, which allows for signaling of intense emotion, is not allowed during REM sleep. This helps to attach emotions to particular experiences, as well as unlearn emotional responses that are too intense or severe.

Mastering one’s sleep is of great importance. This was discussed in episode two of the podcast. To be able to manage one’s sleep life, it is important to be resilient to disruptive events such as travel, stress, changes in school hours or food schedule, which were discussed in episodes three and four. Unlearning troubling emotions is crucial for one to move forward in life. REM deprivation studies have shown that people become hyperemotional and start to catastrophize, which is why sleep disturbances are associated with many emotional and psychological disturbances. Recently, I was in a discussion with Dr. Sarah McKay from Australia, whom I have known for two decades from the time she was at Oxford. Dr. McKay studies menopause in the brain, among other things.

She was saying that a lot of the emotional effects of menopause are not directly related to the hormones. There have been studies showing that the disruptions in temperature regulation in menopause mapped to changes in sleep regulation, which then impact emotionality and an inability to correctly adjust the circuits related to emotionality. I encourage you to look at her work and we may have her as a guest on the podcast in the future due to her knowledge on these issues, as well as issues related to testosterone and those with different chromosomal backgrounds.

Sleep deprivation is not just deprivation of energy or immune function, it is deprivation of self-induced therapy every time we go to sleep. Things like EMDR and ketamine therapies are in-clinic therapies, but REM sleep is the one you are giving yourself every night when you go to sleep. This raises the important question of how to get and know if you are getting the appropriate amount of REM sleep and slow wave sleep.

Well, short of hooking yourself up to an EEG, it’s gonna be tough to get exact measurements of brain states from night to night. Some people are now using devices like the Oura Ring, WHOOP band, or other similar devices to measure the quality, depth, and duration of their sleep. For many people, these devices can be quite useful. Others are simply gauging their sleep by whether or not they feel rested, or if they feel like they are learning and getting better.

There was a study done by a Harvard undergraduate, Emily Hoagland, who was in Robert Stickgold’s lab at the time. This study explored how variations in total sleep time related to learning, as compared to total sleep time itself. One surprising finding of this study was that, in light of everything that had been said and heard about sleep, one can still do some things to get the appropriate amount of slow-wave sleep and REM sleep.

The study found that it was more important to have a regular amount of sleep each night as opposed to the total duration. Improvements in learning or deficits in learning were more related to whether or not you got six hours, six hours, five hours, six hours, that was better than if somebody got for instance, six hours, 10 hours, seven hours, four or five hours. This finding brings relief to people struggling to “get enough sleep” as it is more important to limit the variation in the amount of sleep than just getting more sleep overall. Furthermore, fatigue tends to be when we are tired whereas insomnia leads to sleepiness during the day when we’re falling asleep. Therefore, it is important to aim for consistently getting about the same amount of sleep, as some people just have a lower sleep need.

I find great relief in the fact that consistently getting six or six and a half hours of sleep is more beneficial than constantly striving for eight or nine hours. This is because varying around the mean leads to some nights getting five and sometimes nine. I recall that, for every hour variation in sleep, regardless of whether it was more or less sleep than one typically got, there was a 17% reduction in performance on a particular exam type.

Therefore, it is important to strive for a regular amount of sleep and for some that means going to sleep, waking up, and then going back to sleep. Ideally, one should get the full compliment of slow wave sleep early at night and sleep towards morning, which is REM sleep. To get more REM sleep, there are a couple of different ways, but here’s how to not get more REM sleep.

Drinking a lot of fluid right before going to sleep can help prevent waking up in the middle of the night to use the bathroom. This is because when the bladder is full, there is a neural connection, a set of neurons and a nerve circuit, that goes to the brain stem and wakes us up. Some people use this to try and adjust for their jet lag when they’re trying to stay awake. Having to urinate is one of the most anxiety-evoking experiences anyone can have and it’s very hard to fall asleep or stay asleep when you really have to go to the bathroom. Bedwetting, which happens in kids very early on, is a failure of those circuits to mature until they reach adulthood. The circuits take some time to develop and in some kids they develop a little bit later than others. To avoid disrupting your sleep, it’s important not to go to bed dehydrated.

On the other hand, there is evidence that if you want to remember more of your dreams, there is a tool that you can use. I don’t necessarily recommend it, but drinking a lot of water before you go to sleep tends to break in and out of REM sleep, which makes it easier to recall more of your dreams. This has been studied in laboratories, and people have been found to recall more of their dreams. This is because they are in a semi-conscious state and constantly waking up throughout the night. To avoid having a full bladder before going to sleep, I suggest not drinking too much water. Additionally, during REM sleep there is a shift in neurotransmitters, specifically a decrease in serotonin.

Excuse me, there are a lot of supplements out there geared toward improving sleep. I’ve taken many of them, if not all of them at this point. And I mentioned on a previous episode that when I take tryptophan or anything that contains 5-HTP, which is serotonin or a precursor to serotonin, I tend to fall very deeply asleep and then wake up a few hours later. This makes sense now, as low levels of serotonin are typically associated with slow wave sleep and that comes early in the night.

So for some people, these supplements might work, but be aware serotonin supplements could disrupt the timing of REM sleep and slow wave sleep. In my case, this led to waking up very shortly after going to sleep and not being able to get back to sleep. If you want to increase your slow wave sleep, less serotonin might be the way to go.

Resistance exercise is one of the most powerful ways to increase slow wave sleep, the percentage of slow wave sleep, without disrupting other components of sleep and learning. It triggers a number of metabolic and endocrine pathways which release growth hormone early in the night, leading to greater slow wave sleep. Resistance exercise doesn’t need to be done very close to bedtime, as it could be disruptive for some people. It is involved in motor learning and the acquisition of fine detailed information, as well as emotional components of experiences. For those interested in lucid dreaming, there are simple zero technology tools that can be used, such as setting a queue.

Lucid dreaming is the ability to become aware that you are dreaming while in the dream state. To practice lucid dreaming, one can write down a simple statement about something they would like to experience in their dreams (e.g. “I want to remember the red apple”) and draw a picture of it before going to sleep. Reports suggest that doing this for several days can lead to a situation in which you are in your dream and remember the red apple, allowing you to navigate and shape the dream. Lucid dreaming does not have to involve the ability to alter features of the dream, but can simply be the awareness that you are dreaming. People who have a lot of lucid dreams may become overwhelmed and should try to embrace protocols that set the right duration of sleep. Keeping the total amount of sleep per night to six hours, such that you begin and end sleep at the beginning and end of one of the ultradian cycles, can be beneficial. Finding the right amount of sleep that is right for you and getting it consistently night to night is important.

If you’re a lucid dreamer and you don’t like it, then you may want to start to make sure that you’re waking up at the end of one of these ultradian cycles. It is better to wake up after six hours than after seven, and if you do sleep longer than six hours, you should aim for seven and a half hours. This will reflect the end of one of these 90 minute cycles, as opposed to waking up in the middle.

Alcohol, THC, and most things that increase serotonin or GABA are known to induce pseudo sleep like states. When people fall asleep after consuming alcohol or THC, one of the active components of marijuana, it disrupts the pattern of sleep, depth, and overall sequencing of more slow wave sleep early in the night and more REM sleep later in the night.

There are some things that seem to suggest that you could increase the amount of slow wave sleep using things like arginine, the amino acid arginine. However, you should be aware that arginine can have effects on heart and other effects. Alcohol and THC are not great for sleep and depth of sleep. You might feel like you can fall asleep faster, but the sleep that you’re accessing is not the kind of deep, restorative sleep that you should be getting. Of course, if that’s what you need in order to sleep and that’s within your protocols, I’m not suggesting people take anything. I’m not a medical doctor or a cop and I’m not trying to irregulate anyone’s behavior. I’m just telling you what the literature says.

Some people may want to explore their dreams and the meaning of dreams. There is not much hard data available on how to do this, but many people report keeping a sleep journal. This involves marking when they think they fell asleep the night before, when they woke up and if they wake up in the middle of the night or early in the morning, writing down what they can recall of their dreams. Even if they recall nothing, many people experience mid morning or later afternoon where they suddenly remember they had a dream about something and writing that down. I kept a dream journal for a while and didn’t learn much, except that my dreams were very bizarre. There are some things that happen in dreams associated with REM sleep as compared to slow wave sleep which can tell you if the dream likely happened in REM sleep or slow wave sleep. The distinguishing feature is something called theory of mind, which was developed for the study and assessment of autism.

Simon Baron Cohen developed the concept of Theory of Mind, which is a psychological and neuroscientific assessment done on children. In a Theory of Mind test, a child is brought into a laboratory and watches a video of another child playing with a toy. At the end of playing with the toy, the other child puts the toy in a drawer and leaves. The experimenter then asks the real child in the experiment what the other child is feeling or experiencing. Most children five or older have the capability to answer the question and demonstrate Theory of Mind, which is the ability to put their ideas and mind into what the other child is likely to be feeling or experiencing. This assessment is used as one of the assessments for autism, as some children with autism or that go on to develop autism do not have this theory of mind.

Theory of mind is something that emerges early in life as a part of the maturation of the circuits in the brain associated with emotional learning and social interactions. We experience this in certain dreams. If you had a dream that you’re puzzled about, or that you’re fixated on and you’re thinking about, you might ask, “In that dream was I assessing somebody else’s emotion and feeling, or was I very much in my own first person experience?” Theory of mind tends to show up most in these REM associated dreams, although this isn’t a hard and fast rule.

Chances are if you were in a dream and you were thinking about other people who wanted to do something to you, you were thinking about their desire to chase you or help you, or something that was related to someone else’s emotional experience. This dream occurred in rapid eye movement sleep as opposed to slow wave sleep. This makes sense when you think about the role of REM in emotional unlearning of associations with particular life events. REM is rich with all sorts of exploration of the emotional load of being chased, or the emotional load of having to take an exam the next day, or being late for something.

Today we’ve been in a deep dive of sleep and dreaming, learning and unlearning.

Recapping a few of the highlights and important points, we have more slow wave sleep and less REM early in the night, and more REM and less slow wave sleep later in the night. REM sleep is associated with intense experiences without the chemical epinephrine that allows us the anxiety or fear, and is thought to have an important role in uncoupling emotion from experiences. Slow wave sleep is critical for motor learning and the learning of specific details, while REM is associated with emotions and general themes and meaning.

I personally find it fascinating that consistency of sleep (meaning getting six hours every night) is better than getting ten one night, eight the next, five the next, four the next. This is something I can control better than just trying to sleep more, which I think a lot of people can relate to.

This episode brings us to the conclusion of a five episode streak where we’ve been focusing on sleep and transitions in and out of sleep, non sleep depressed. We’ve talked about a lot of tools, such as morning light, evening light, avoiding lights, blue blockers, supplements, and tools for measuring sleep duration and quality. By now, you should be armed with a number of tools and information, such as knowing when your temperature minimum is, when you should view light or not, when you should eat or take hot showers, or even a cold shower (which most people, including me, loath but can have certain benefits). This will allow you to shape your sleep life and get a consistent amount of sleep on a regular basis. As a joke, I sometimes tell people that someone should start something on intermittent sleep deprivation, although we’re already doing that.

We are all experiencing lack of sleep from time to time. And while it can be tempting to catastrophize this, I think the best approach is to adjust and get back on track with a consistent amount of sleep. There are many tools available to help us relax and stay asleep, and most of them are free. If you heard Costello snoring throughout this episode, I apologize on his behalf – he’s an integral part of the podcast!

It allows us to rewire our brains and create new habits and pathways.

A few people have said that the noise in the background is disruptive. I can understand that, but I can’t change the fact that Costello, my ten-year-old bulldog mastiff, is nearing the end of his lifespan. I’m not trying to make anyone feel guilty, but when he’s gone there won’t be any snoring. I might get a different dog, but I’m sorry not sorry about the snoring. I’m genuinely sorry if it’s disruptive, but he’s here for the hall.

We are now closing out the segment on sleep and moving into a new theme and topic for the next four to five episodes. We will be discussing the science and tools related to neuroplasticity, a remarkable feature of the nervous system that allows us to rewire our brains and create new habits and pathways.

The nervous system has the unique ability to change itself in response to experience – this is what makes us as individuals and as a species. Our knowledge, capabilities and potential are all set by the limits of neuroplasticity. We will explore topics such as learning in childhood and adulthood, sensory and motor plasticity, language acquisition, emotional breadth and the relationship between plasticity set during childhood attachment to parent or other caregiver and adult relationships.

Many of you have probably heard about secure and insecure attachment, referred to as the A, B and C, D babies from the classic studies of Bowlby and others. Now, however, neuroscience can explain which circuits were active during those early life attachments and how those map to adult attachment styles, challenges, and partner selection. We will also be discussing supplements, chemicals, machines, and devices that can aid in the plasticity process, as well as cases where delaying plasticity can lead to more depth of learning and longer lasting results. This literature is very exciting and I hope that the knowledge acquired so far is helping you with self evaluation and experimentation, and allowing you to not just sleep better, but also feel better while awake. This should set the stage for learning more about neuroplasticity as we go through the month.

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I personally get my supplements from Thorne, as they have the highest level of stringency and precision in terms of what’s in the bottle, as well as very high quality standards. They are partnered with the Mayo Clinic and major sports organizations.

You can try Thorne supplements at thorne.com/u/huberman and get 20% off anything they provide. A few people wrote to me with questions/corrections about things I said in previous podcasts. In keeping with my goal of making the information accurate and clear, I want to correct myself about a few things I said. One of these was that testosterone is made by the sertoli cells of the testes, which is not correct. It is made by the leydig cells of the testes, and I want to make sure I clarify that.

Testosterone is made by the Leydig cells of the testes, not by the Sertoli cells. The Sertoli cells make 5 alpha-reductase and aromatase, and some other enzymes involved in conversion of testosterone into things like DHT and estrogen. I genuinely appreciate the correction.

I also misspoke when I said “typical temperature is 96.8 when I actually meant to say 98.6”. It was a dyslexic slip on my part, though I don’t know that I’m clinically diagnosed with dyslexia. I apologize for the mistake, as temperature does vary a lot across the day and night, as I mentioned in a previous podcast.

We cannot talk about average temperature, but many people think of it as 98.6. I apologize for my mistake.
Thank you for joining me in exploring the fascinating landscape of the nervous system in biology and understanding the mechanisms that define us and our sleep and wakefulness. I hope you are finding the information useful. I am grateful for your interest in science. [upbeat music]