In this Huberman Lab Essentials episode, I discuss interoception, the brain’s ability to sense and interpret signals from the body, which shapes our sense of self and underlies vital functions like focus, sleep, healing and emotions. I explain how the body communicates different types of information to the brain, influencing processes like digestion, heart rate and immune function. I also describe practical tools such as breathwork to regulate alertness, strategies to support gut health and reduce sugar cravings, and awareness practices to enhance interoception. By understanding and applying these tools, you can strengthen the brain-body connection to improve mood, overall health and performance. Read the episode show notes at hubermanlab.com. Huberman Lab Essentials are short episodes focused on essential science and protocol takeaways from past full-length Huberman Lab episodes. Watch or listen to the full-length episode at hubermanlab.com. Thank you to our sponsors AG1: https://drinkag1.com/huberman Eight Sleep: https://eightsleep.com/huberman LMNT: https://drinklmnt.com/huberman Timestamps 00:00:00 Sense of Self, Interoception 00:01:25 Brain & Body Communication, Vagus Nerve, Mechanical & Chemical Information 00:04:43 Lungs & Diaphragm, Tool: Breathwork for Alert or Calm 00:09:47 Sponsors: AG1 & Eight Sleep 00:13:14 Brain & Gut Communication, Tool: Reduce Sugar Cravings 00:18:27 Brain, Gut Chemistry, Inflammation & Gut Microbiome, Tool: Fermented Foods 00:22:20 Sponsor: LMNT 00:23:52 Vomiting, Brain; Tool: Reduce Nausea 00:28:52 Fever, Brain Chemistry, Tool: Cooling Body 00:33:20 Vagus Nerve, Emotions, Mood, Tool: Heart Awareness 00:39:29 Recap & Key Takeaways Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices
Chapter 1: What is interoception and why is it important?
Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are going to talk about our sense of self, or what's called interoception.
Chapter 2: How does the brain communicate with the body?
Interoception is our sensing of our internal landscape, things like our heartbeat, our breathing, and our gut. This discussion about sense of self and interoception has many important actionable items that relate to bodily health and brain health.
Of all the topics I could cover, this thing that we call sense of self, which is also called interoception, has perhaps the most foundational level of importance for all that we feel, all that we do, and all that we are capable of doing. And I promise that if you can learn a little bit about the mechanisms of self-sensing,
of understanding what's going on in your internal milieu, as we say, your internal environment, you will position yourself to do some very simple things that can lead to outsized positive effects on everything from sleep to body composition, to mental focus, to mood, your ability to regulate stress, and indeed even your ability to heal and recovery from injuries of different kinds, brain injury and bodily injury.
Chapter 3: What role does breathwork play in regulating alertness?
we have a system in our body that connects our brain to all of our bodily organs and connects all of those bodily organs to our brain. And that communication between brain and body in both directions creates a situation where either we are positioned to do things well, or we are positioned to do things poorly.
So I really want to dive in and dissect what is this system of brain-body communication? What does it look like? What are the actual neurons and connections? The system that's most often associated with this is our 10th cranial nerve called the vagus nerve. The word vagus relates to the word vagabond, which is to wander. And indeed the vagus nerve is a vast, So it's not one nerve.
It's not like one fiber, one axon, as we say. So where do they go? Well, they leave the brain and the brain stem. The brain stem is kind of the back of your brain. If you touch the back of your neck, it's about three inches deep to where you're touching. The neurons that are there send information into the body to control your bodily organs.
how fast your heart is beating, how fast you're breathing, how fast your digestion is occurring. Even things like whether or not you are going to secrete so-called killer cells, your immune cells from your spleen to go ward off bacteria. Now the neurons there don't know what to do. unless they receive information about what's going on within the body.
So everything from your intestines to your stomach, et cetera, and your spleen are sending information also up to the brain. There are two fundamental features of what's going on in your body that need to be communicated to your brain, these neurons in your brainstem, in order for your brain and your body to work together correctly.
And the two types of information are mechanical information and chemical information. So when you think about your sense of self and your ability to understand what's going on in your body, if you feel good or if you feel bad, your sense of self is dependent on these mechanical phenomenon and these chemical phenomenon. If your gut is full or empty,
Whether or not your heart is beating fast or beating slowly, that's mechanical. And chemical information, whether or not your gut feels nice and whether, you know, when I say nice, I mean, whether or not it has a balance of acidity and alkalinity that feels right to you or whether or not your gut feels off. It doesn't feel quite right. That's chemical information.
So the first principle that everyone should understand about their sense of self is that they are sensing mechanical and chemical information about every organ in their body. except for one, and that's the brain. Your brain actually doesn't have pain receptors. It doesn't even have touch receptors. The brain is a command center. It helps drive and govern changes in the organs of the body.
So your organs are different. They need to tell your brain what's going on. And there are ways that you can control the mechanical and the chemical state of your organs in ways that are very powerful.
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Chapter 4: How can gut health influence brain function?
So let's talk about how you can adjust the mechanical and chemical environment of your organs in order to make your brain better and how your brain can make the mechanical and chemical environment within your organs function better. Let's take one example of these and explain how mechanical and chemical information from this particular set of organs
communicates to the brain and how that changes how our brain works. And the organ I'd like to focus on first are the lungs and the diaphragm. So we're all familiar with our lungs, these two big bags of air, but they're actually not two big bags of air. They actually have little tiny sacks within them, actually millions of little sacks called the alveoli of the lungs.
The alveoli of the lungs are like little tiny balloons throughout our lungs. Those little bags of air can fill up or they can deflate, right? Just like your lungs overall can fill up or they can deflate. The diaphragm is a muscle and it sits below our lungs. And the way the diaphragm and the lungs work together is very interesting. The diaphragm is actually skeletal muscle.
So it's just like a bicep or a quadricep. And the fact that it is skeletal muscle is important because it has a unique property, which is that you can control it voluntarily. How the diaphragm moves up and down determines how you breathe. How you breathe is also dependent on little muscles that are between your ribs. the intercostals and other muscles.
When we inhale, these little sacks in our lungs fill up and our lungs expand. And when we do that, we take up space in our thoracic cavity and our diaphragm moves down, okay? When we exhale, the diaphragm moves up the lungs get smaller, okay? This actually controls our heart rate and it works in the following way. Our heart actually has a little more space because the diaphragm's moved down.
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Chapter 5: What tools can help reduce sugar cravings?
So the heart gets a little bit bigger, physically bigger, not in the emotional sense, but physically bigger. And as a consequence, whatever blood is in the heart flows at a slower rate because it's a larger volume. So bigger volume heart, same amount of blood inside the heart means slower flow. The brain registers that because there are a set of neurons on the heart called the sinoatrial node.
That information is registered by the brain and the brain sends a message back to the heart to speed the heart up. So if you do long inhales or you inhale more vigorously, you actually are speeding your heart up. Now, of course you have to exhale as well. But for instance, if I were to inhale very long, like the entire time, my heart rate is increasing.
And then if I did a quick exhale, something else will happen. But if I kept doing that, my heart rate would increase. It's not going to increase linearly and forever, but it will increase with each inhale. Or I can simply make my inhales more vigorous and my heart rate will speed up. This is an autonomic and automatic relationship between the diaphragm, the lungs, the brain, and the heart.
Now, if inhale speed the heart up, what happens on exhales? When we exhale, the diaphragm moves up. The heart has less space, meaning it gets a little bit smaller, which means that whatever volume of blood is inside the heart moves faster through that smaller volume. That information is sent to the brain via the collection of neurons called the sinoatrial node.
The brain then sends information via the vagus nerve back to the heart to slow the heart down. So while inhales speed up the heart, exhales slow the heart down. And you can leverage this in a very powerful way to set the conditions of your mind. If you want to be more calm, emphasize exhales. And the simplest way to do this is to emphasize exhales through what's called a physiological sigh.
Two inhales followed by a long exhale. Those double inhales are kind of important because what they do is they maximally fill all those little sacks in your lungs. And then when you breathe out, you're exhaling as much of the carbon dioxide in your system as possible. When you make exhales longer, you're slowing your heart rate. You're calming down. The opposite is also true.
If you inhale deeply or vigorously and then exhale less long or less vigorously, you will increase your level of alertness through these purely mechanical aspects of your interoception. It only takes two or three of those before you start to feel more alert. And that's because your heart rate is increasing.
And actually, if you keep doing that for 25 or 30 breaths of inhale deep, short exhale, you will start to secrete a lot of adrenaline. You will actually feel as if you've had a couple espresso. You will immediately wake up.
through purely mechanical means, changing the way that you breathe, emphasizing inhales or exhales or keeping them the same will change the way that your brain works, how alert you are and how well you function in anything. And again, this doesn't mean that breath work has no value.
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Chapter 6: How does the vagus nerve affect emotions and mood?
Again, go to drinkag1.com slash Huberman to claim the special welcome kit with five free travel packs and a free bottle of vitamin D3 K2. Today's episode is also brought to us by Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity.
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The audio catalog includes several NSDR scripts that I worked on with Eight Sleep to record. If you're not familiar, NSDR involves listening to an audio script that walks you through a deep body relaxation combined with some very simple breathing exercises. NSDR can help offset some of the negative effects of slight sleep deprivation.
And NSDR gets you better at falling back asleep should you wake up in the middle of the night. It's an extremely powerful tool that anyone can benefit from the first time and every time. If you'd like to try 8sleep, go to 8sleep.com slash Huberman to get up to $350 off the new Pod 5. 8sleep ships to many countries worldwide, including Mexico and the UAE.
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Chapter 7: What are the key takeaways for improving health?
Again, that's 8sleep.com slash Huberman to save up to $350. So now I want to shift away from breathing and diaphragm and lungs and move toward another organ within our viscera, which is our gut. So this includes our stomach and our intestines, our esophagus and so forth. It's been said before, both by me and by others, that we are but a series of tubes. And indeed that's true.
Believe it or not, every system in your body is a tube. Your brain is actually a tube that connects to your spinal cord, which is also a tube. Your digestive system starts with the tube at your mouth and Of course, it goes down through your throat, and then you've got all the elements of the stomach and the intestines, and then it comes out the other end.
So you are but a series of different tubes, your vascular system, a series of other tubes. The way your digestive system works is to communicate to your brain about the status of the mechanical pressures along this tube, so within your stomach and your intestines, et cetera, and the chemical status of that tube at various portions within that tube.
to inform your brain about how your brain should control that tube. So let's start with the mechanical sensing of your gut. If you drink a lot of fluid, or if you eat a lot of food, your gut will fill up. If there's a lot of that food, pressure receptors communicate to the areas of your brain that are involved in feeding and will say, don't eat anymore. You don't need to consume anymore.
The converse is also true. When these receptors signal to the brain that the gut is empty, So when you find yourself at the refrigerator or you find yourself almost, you know, manically trying to get food of different kinds, you're not even thinking about what you're eating because you're so hungry.
In part that's because the lack of food in your gut has sent that information to your brain and is driving particular fixed action patterns that are associated with eating. So if you've eaten anything, even if it's a small volume of food in the last hour to three hours,
It's actually a worthwhile practice to take a few moments, maybe 10, 20 seconds, and actually just try and concentrate on sensing the neurons in your gut and how full you are. The consequence of that is actually rather interesting. It's been shown that the consequence of that is actually that you can better override the signals of gut fullness or emptiness.
So there are other ways that our guts communicate with our brain. It's not just our stomach talking to our brain. It's also our intestines talk to our brain. The Lieberle's lab, the guy's name is Steven Lieberle. He runs a lab at Harvard Medical School. They discovered a category of neurons called the GLP-1R neurons.
And those neurons send little wires down into the intestines and deep into the stomach, but mostly into the intestines. and they sense stretch of your intestines. And then those neurons send another branch.
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