The Dr. Hyman Show - Your Nervous System Controls Your Gut, Hormones, and Weight — Here's How to Fix It

Episode Date: July 6, 2026

You've cleaned up your diet. You're taking the supplements. You're exercising, sleeping more, and doing everything "right." So why do you still feel exhausted, inflamed, anxious, or stuck? In this encore episode—one of the most impactful Office Hours conversations we've shared—I explore a question that could change the way you think about healing: What if your nervous system is the missing piece? When your body doesn't feel safe, it prioritizes survival over repair, affecting everything from your metabolism and hormones to your gut, immune system, and brain. In today's episode, I break down: Why chronic stress changes your biology—and how nervous system dysregulation can drive inflammation, hormone imbalance, digestive issues, weight gain, and autoimmune disease The difference between living in constant "fight-or-flight" versus a regulated nervous system that supports healing, resilience, and recovery Simple, science-backed strategies to regulate your nervous system, including breathwork, blood sugar balance, strength training, sleep, and daily safety cues Why you can't out-supplement or out-biohack chronic stress—and how creating physiological safety unlocks your body's natural ability to heal Healing isn't just about finding the right supplement or following the perfect diet. It's about creating an environment where your body feels safe enough to repair itself. When you begin working with your nervous system instead of against it, everything else—from your energy and metabolism to your mood and resilience—can start to change. Check out my full conversation with Dr. Scott Sherr HERE. Track your health with Function Health: https://functionhealth.com/mark (Use code MARK2026 for $50 off your membership.) Have a question you’d love answered on Office Hours? Submit it here Resources Mentioned: Listen to my full conversation with Dr. Scott Sherr on nervous system regulation and mitochondrial health.

So yes, nervous system regulation may be the missing piece. Because you can't out-supplement chronic stress signaling. You can't biohack your way out of a body that feels unsafe. Healing requires physiological safety. Welcome back to office hours. As part of our summer replay series, we're revisiting some of the conversations that sparked the biggest response from our audience. And this one is one that clearly struck a nerve.

Many of us spend years trying to optimize our health. We clean up our diet. We take supplements. We improve our sleep. and run every imaginable test. Yet sometimes we feel stuck. What made this episode resonate with so many listeners is that it explores a different question altogether.

What if the issue isn't your gut, your hormones for your metabolism? What if the real problem is that your body truly never feel safe enough to heal? In this conversation, I unpacked the powerful role of the nervous system and regulating everything from inflammation and blood sugar to digestion, sleep, mood, and recovery. is a perspective that has become increasingly important and one that many people find surprisingly relevant to their own health journey.

Whether you're hearing it for the first time or coming back from the listen, I think you'll find yourself looking at stress, resilience, and healing in a completely different way. Let's dive in. This episode was brought to by Function. Get access to over 160 labcus annually at Functionhealth.com slash mark.

Today I want to talk about something that might be the basic link in your health. You clean up your diet, you're taking your supplements, you're trying to sleep more, maybe even run labs and to work with practitioners. But maybe you're still wired or exhausted or inflamed or just stuck in your health. What if your issue isn't your gut, your hormones, or your metabolism? What if the real issue is your nervous system?

Because here's the truth. Your body cannot heal if it thinks it's under threat. So today we're going to unpack what nervous system regulation actually means and what a regulated nervous system looks like and whether calming your internal stress response might be the key that unlocks healing. This isn't just about stress management, it's about biology.

When I was in training to learn all about this stuff after medical school, because that was just the beginning, I took a course with a guy named Herbert Benson, and he said that stress either causes or worsens 95% of all illness. That's a big deal, and we should pay attention to that. In functional medicine, we talk a lot about inflammation.

We talk about insulin, we talk about hormones, we talk about toxins, all important. But underneath all of it is one master regulator, your nervous system. So what is your nervous system really? Let's simplify this. You have two main branches of your nervous system, the sympathetic system, which is fight or flight,

and the parasympathetic system, which is the rest, digest, and repair, the relaxation nervous system. The sympathetic system mobilizes you. It makes your heart rate go up, it raises your blood sugar, it redirects energy away from digestion, and primates you for action running from a tiger or getting in a fight.

Not bad if you're surviving. It's essential. But the parasympathetic system is where healing happens. It's where digestion happens, where detoxification happens, where hormone regulation happens, where immune repair happens. And then there's the vagus nerve, which is a major communication highway between your brain and your body. It connects your brain to your gut, to your heart, to your lungs, to your immune system.

So when we talk about nervous system regulation, we're really talking about your body's ability to shift fluid between activation and recovery. The key word is how to be adaptable here or adaptability. Regulation doesn't mean being calm all the time. It means you can experience stress and then return to baseline. It's a great book called Why Zebras Don't Get Ulcers by Robert Sapolsky, who's one of the key scientists who's helped us understand stress. And the reason zebras don't get ulcers is because when the lion chases them,

they run like hell, freaked out, the lion catches one of the zebras, then goes about eating it, and all the other zebras just stop running, and they stand around the line while they're eating another zebra, and their nervous system just calm right down. That's why they don't get ulcers.

We just stay chronically stressed all the time. Now, the critical insight from functional medicine is this. Your nervous system sets the tone for every other body system. So what does dysregulation of your nervous system actually look like? Well, most people don't realize, or dysregulated because it just feels normal. Let me paint you a picture.

If you're chronically in sympathetic mode, that's sympathetic nervous system activation, stress response, you might experience a lot of things. You might feel tired, but wired. You might be anxious and irritable. You might have digestive issues, constipation or diarrhea or irritable bowel syndrome. You might have blood sugar swings.

You might get panic attacks. You might wake up at two or three in the morning. You might have belly fat that won't budge. here's a little tip for you your nervous system is connected to your fat cells and this is actually scientifically true i've written about them in my books the nervous system innervates fat cells or adipose tissue and when you're stressed it makes them get more fat it makes you gain more weight that's not a good thing it also affects hormone swings autoimmune players we know they just actually regulating your vagus nerve,

they can regulate their vagus nerve through various implantable devices now and cure rheumatoid arthritis. There was a study that I wrote about years ago where people who just journaled who had rheumatoid arthritis for 20 minutes a day about their authentic feelings, had a dramatic reduction in symptoms

better than most medications. Also, chronic stress raises cortisol. It causes then elevations in blood sugar because, you know, when you're stressed, you want to have high blood sugar, but not all the time. And then when you have high blood sugar, you become insulin resistant,

and when you become insulin resistant, that causes inflammation. Then when you have inflammation, that disrupts your hormones even more. It causes gut damage. It causes changes in your immune system. Now you're chasing symptoms. When the upstream driver is your stress signaling response.

Now, on the other side, some people swing into what we call vagal shutdown. This is the freeze response. What does that look like? Well, fatigue, brain fog, low motivation, depression, feeling numb and disconnected. Many people balance between both states, wired and exhausted at the same time.

So tired and wired. It's not weakness. It's just nervous system dysregulation. So what does regulation actually look like? What does it look like to have a regulated nervous system? It's not constantly being calm. It's resilience. And a regulated nervous system means you can handle stress without spiraling.

You can digest your food well. You can sleep deeply. Your mood's relatively stable. Your heart rate variability improves. You recover faster from setbacks. Regulation is about recovery speed. It's about flexibility. It's about metabolic safety because your body feels safe and turns on the repair system.

When your body feels threatened, well, it prioritizes survival. And survival mode means shutting down long-term healing. Okay, so could this be the missing link to healing that we've been looking for? Well, let's connect the dots. If you're trying to heal your gut but you're chronically stressed, well, your microbiome shifts in response to the stress hormone. So you literally change your microbiome with, stress. If you're trying to balance hormones, but cortisol is elevated, it steals from the progesterone and other pathways that regulate your sex hormones. You're trying to lose weight and you're in

constant fight or flight while your insulin stays high. If you're dealing with autoimmunity, well, stress directly affects the immune signaling and your immune system's health. So yes, nervous system regulation may be the missing piece because you can't out supplement chronic stress signaling. You can't biohack your way out of a body that feels unsafe. Healing requires physiological safety. How do you regulate your nervous system? Let's make this practice. Number one, stabilize your blood sugar. Unstable blood sugar is interpreted as a threat. And let me tell you how to do that. Start your day with protein, really important. Balance every meal with protein healthy fat and fiber. Reduce or I don't even like the word reduce. I would just say never eat ultra-process food. There's no reason to eat Twinkies or

Pop-Tarts or luncheballs or go-gurts or any of the million things. that are in the grocery store shelves that are not actually food. Just eat food. Listen to Mike Tyson, eat real food. This alone dramatically calms your stress signaling. Next, use your breath. One of the fastest ways to shift into the relaxation response to the parasympathetic mode is your breath.

So you can try this. Just inhale through your nose, and then take a second short inhale, and then exhale fully and slowly through your mouth. That long exhale, activates your nervous system. I just did it. I feel relaxed already. Two minutes can change your state. Literally, just try, even five breaths can change your state. Just do five deep breaths, profound and rapid change. You always have that accessible to you. To keep your skin in check this summer,

you have to check your health. I know that's not where you're used to hearing, but after decades in medicine, you need to know this. The glow of your chasing doesn't start with creams and serums. It starts in the blood. Your skin is an organ. In fact, it's your largest organ and like everything else inside your body, your skin health depends on your nutrient status, your inflammation levels, your liver function, even your environment. So you can spend money on the latest treatment or you can look beneath the surface to get to the source. That's exactly why we built function. Function gives you access to 160 plus lab tests annually that measure signals in your blood, including nutrients, liver health, inflammation, and hormones. You can also complete your health

baseline with an annual MRI that helps you see organs, tissues, and other changes. Check your Health at functionhealth.com slash mark. And if you're one of the first 1,000 people this week, use the code Mark 2026 for a $50 credit under $365 a year membership. Next, pro tip is build muscle. Muscle isn't just about looking good or aesthetics. It improves insulin sensitivity and increases mitochondrial density, but it also enhances stress resilience. So strength training is one of the most powerful nervous system stabilizes what we have, because muscle is your metabolic armor. Next, protect your sleep. Because when you're sleep, it's not good, you're in trouble.

Sleep is when your body and your nervous system recalibrates. So how do you fix your sleep? Get morning light exposure. Sleep at a consistent bedtime. Not always ideal, but can. Reduce your evening stimulation, so don't do stimulating things right before bed. Avoid blood sugar crashes before bed

because meaning don't eat a lot of sugar and starch at dinner. If you don't sleep, you can't regulate. So make sure you prioritize sleep. Next, you want to create safety cues. The nervous system responds more to cues of safety than to positive thinking. So what is that? Nature, connection, community, touch, laughter, time offline, which I love. Your biology is always scanning for safety. Just give it those signals. They're available to you. All right. What are the myths

about nervous system regulation when it comes to nervous system function? Is nervous system regulation just meditation? No. It's metabolic. It's relational. It's physiological. If I'm productive and high achieving, I must be regulated. Not necessarily. I'm an example of that. You may be as you running on adrenaline, which I did for many years. Can I biohack my way out of stress? Well, not if your lifestyle stays chaotic. If I calm down or lose my edge. Well, actually, regulation improves focus, performance, and clarity, so you do better. So here's the bottom line. A regulated nervous system is not a luxury. It's the foundation of healing. If you feel stock, whether it's weight gain, hormone dysfunction, gut issues, inflammation, just ask yourself,

does my body feel safe? Because healing happens in safety. So start small. Balance your breakfast, lift something heavy, breathe for two minutes. Every morning I wake up and I do a breathwork practice for five minutes. It's amazing. I love starting my day like that. Go outside. Get some fresh air, get some sunlight, prioritize your sleep. You don't heal by fighting with your body. You heal by teaching it that it's safe to repair. And when you do that, everything changes. Now, if you want to go deeper, I want you to keep an eye out for my upcoming episode

on my podcast with Dr. Scott Cher. We're exploring the emerging theories and the practical tools for regulating your nervous system and unlocking the body's healing capacity. Take a listen to this short clip from our conversation. Today, really want to have people who are listening to understand, you know, what is going on with their energy, what is going on with stress,

what are the psychological and the physiological cause of stress? And how do we start kind of navigating this from a therapeutic perspective? Because we all want out of this. I, as soon as like, yeah, I'm in this empathetic spiral of doom, and I don't want the hell out of this thing. So what is it? Explain to us, unpack it for us. Well, thanks again for having me, Mark.

And, you know, what I like to just describe here is it's not a diagnosis for people. This is more of a pattern. As you mentioned, it's an age-old pattern. but I realized recently that it was really a significant discovery for me to understand that it's a spiral and it's a loop. You have sympathetic activation, which is your fight or fight, your nervous system being activated. You have mitochondrial dysfunction. Mitocondrial dysfunction, mitochondria, as all your listeners know, is a part of their cells that make energy. The combination of sympathetic activation in mitochondrial dysfunction is a loop.

And what happens here is that this loop can either start with mitochondrial dysfunction directly. that's what I call bottom up, or it can start with sympathetic activation from outside stressors. Say it's your job, your relationship, you have a snoring partner that is snoring and you can't get to sleep at night, outside stresses, or even like worse things like trauma or things that happen when you're younger that have maintained you in this place where you can't stay safe. Either way, whether it starts with mitochondrial dysfunction directly or it starts with sympathetic activation externally or for most people, it's both. Yeah. And then it's something that just makes you fall off a cliff. It could be... Let me apologize you a first sec.

Just define sympathetic activation. Yeah. People are like, what is that? And define like a little bit better mitochondria. Sure. Because these are central to your thesis of the sympathetic. So let's get our terms right because I think if you are like, well, otherwise, I'll be just talking doctor stuff.

I'm sympathetic, you know? I'm sympathetic. No, no, no. It's not bad. Yeah, no, good point. So, yeah. So I feel them sympathetic to those that are in sympathetic. The sympathetic nervous system.

So sympathetic is your fight or flight part of your nervous system. So it's your, it's your, it's, right? running away from the proverbial saber-tooth tiger, as we somehow always refer to. I know, right. I don't know why. But you're getting chased by something. Yeah.

But unfortunately, we're getting chased all the time in modern society, whether it's with our phones that are actively in our faces all the time and doom scrolling at 3 o'clock in the morning going, why is this the way it is? Or it's outside things like your job or your relationship. But we're not, we don't reward people resting or relaxing. So the sympathetic nervous system is part of your autonomic nervous system.

You have your sympathetic branch, which is your activation, fight or flight, and you have your parasympathetic, which is your rest, digest, detoxify, and heal. But modern society doesn't reward that side, right? It rewards the hustle. I mean, in medical school, my friends and I had shirts that said, sleep is for quitters.

Not surprising. I grew up in New York. Surgeons don't have lunch. That was ours. There you go. Same kind of thing. Like, you just, you hustle, right? You go and you grind, right?

That's what we reward. And then, unfortunately, that's how society has created this, stress externally for us that we have to perform, we have to have more meetings, we have to do more, do more, do more all the time. And so instead of just running away from the Sabre 2 Tiger and then, you know, hanging out the rest of the day because hopefully we lived, maybe we probably didn't, but in some cases we did, right? Then you would have the time to relax because your nervous system would be activated and then it would be shut off. But that's not how modern society works anymore, as you know. We're constantly stressed, constantly on pressure, constantly on meetings. And that's that

sympathetic activation. And most of us kind of think we thrive in that, in that environment, and we can for a little while. But the problem is that when you're sympathetic all the time, you're releasing hormones like cortisol, your neurotransmitters like noraphenephrine and epinephrine. And adrenaline. And adrenaline. Yes. Noradrenaline and adrenaline that are stimulating the whole system to work harder. Because if you're in that sympathetic nervous system activation all the time, I call it sympathetic overdrive, you're just shoving all those neurotransmitters and hormones out all the time. And that causes deterioration in immune system function, in hormones function and in your mitochondria itself. So to define mitochondria, which we can do now,

the mitochondria are part of the cell that helps make energy, right? When I was in high school, my daughter is in ninth grade. She learned she's got the basic cell. She just learned, she's like, dad, she got the basic cell. It's got a nucleus. It's got cytoplasm. It's got goldie bodies. And it's got this one little cool organelle called a mitochondria. I'm like, huh, this is what I learned when I was probably that age too. You learn that the cell has one mitochondria. But that is far from the It has like thousands. Some cells in our body have thousands of mitochondria per cell. And some cells, actually, there's one human cell that has zero.

And that's the red blood cell. Yeah, the red blood cell. Right. But most mitochondria per cell are in our reproductive organs. Eggs, oocytes, sperm are the number one and number two. They've got to swim pretty. And legal energy to swim. Yeah.

And the eggs have more, though. Women have to, you know, create and make the baby. And so they have more. But just behind that is your brain, your heart, your liver, your musculoskelete tissue. So detox, everybody is hugely eugenically. intensive. Yeah, liver is. People don't realize that.

It's like if you need it, if you're going to be able to detox, you have to have a huge amount of mitochondrial energy. So you remember, you are not powerless in this process. You have far more influence over your biology than you've been told. When you learn to work with your nervous system instead of against it, you take back control of your health. And that's where real transformation begins. Thanks for joining me for office hours.

I love diving into these topics with you. Remember, you are the CEO of your own health. And every choice you make. can move you closer to healing and vitality. I want to keep these episodes as relevant and useful as possible, so tell me, what do you want to explore next? What questions are you wrestling with? What breakthroughs are you chasing?

Share your ideas in the comments on social media or through the link in the show notes. I'm listening. Until next time, keep taking charge, keep asking questions, and keep showing up for your health. If you love this podcast, please share it with someone else you think would also enjoy it. You can find me on all social media channels at Dr. Mark Hyman. Please reach out.

I'd love to hear your comments and questions. Don't forget to rate, review, and subscribe to the Dr. Hyman show wherever you get your podcasts. And don't forget to check out my YouTube channel at Dr. Mark Hyman for video versions of this podcast and more. Thank you so much again for tuning in. We'll see you next time on the Dr. Hyman Show. This podcast is separate from my clinical practice at the Ultra Wellness Center, my work at Cleveland Clinic and Function Health, where I am chief medical officer.

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