Speaker 1:
Welcome to the Dr. Gundry Podcast, where Dr. Steven Gundry shares his groundbreaking research from over 25 years of treating patients with diet and lifestyle changes alone. Dr. Gundry and other wellness experts offer inspiring stories, the latest scientific advancements, and practical tips to empower you to take control of your health and live a long happy life.

Stephen Gundry:
So what if the future of medicine isn’t pharmaceuticals but electricity? And what if the key to treating depression, arthritis, even memory problems, lies in a nerve running right through your chest? Well, my guest today is Dr. Kevin Tracey, president and CEO of the Feinstein Institutes for Medical Research, a pioneer in vagus nerve science, an actual neurosurgeon and author of the new book, The Great Nerve. His groundbreaking discoveries from the inflammatory reflex to the field of bio-electronic medicine are transforming how we understand and treat certain diseases.
Now, after a quick break, we’ll explore what this breakthrough means for your health, the simple ways you can start supporting this powerful nerve at home and how medicine itself may be about to change forever. So we’ll be right back. You’re not going to want to miss this one because this is brand new for most of my listeners.
Dr. Tracey, great to have you on the program. Welcome. Thanks for being here.

Dr. Kevin Tracey:
Thanks for having me on. It’s great to be here.

Stephen Gundry:
So let’s dive in. Now, your journey, as I read in your book, began with a tragic loss of a young patient to sepsis. So how did that moment set you on a path towards discoveries that could change how we treat chronic disease?

Dr. Kevin Tracey:
It was 1985. I was a neurosurgery resident at the New York Hospital at Cornell Medical Center, now called Weill Cornell in New York City. And I had known for most of my life that I wanted to combine a career in science, looking at ways of inventing or discovering therapies with a career in neurosurgery. So rotating through the burn unit at the New York Hospital as part of my neurosurgery training, I came to be the physician treating a 11-month-old girl named Janice. She had been terribly scalded in a household accident. Her grandmother actually spilled boiling water on her in the kitchen when she was cooking dinner, turned and drained this pot of water in the sink and tripped over Janice. It was tragic and sad. And despite the severity of this injury and the prognosis was gray from the minute she arrived in the emergency room, she was miraculously bouncing back from one bout of medical crisis to another. And we actually started thinking she might go home.
But I was standing in the doorway to her room watching her feed from a baby bottle at lunch hour and her eyes rolled up in her head and she arrested. Her heart stopped. I ran into the room, I put her in the crook of my arm and gave CPR. The nurse called the code. The code went for what felt like hours, and she was gone. And when I told her mother what had happened, that Janice had passed, the poor woman fell into a faint.
It was a sad, unforgettable story because she was so innocent. And if anything could make it worse, it was that we really didn’t know why she died. One minute she seemed like she was maybe going home and the next she was gone. And the dogma at the time was that she had gone into septic shock from toxins made by bacteria that we didn’t see, we didn’t find infection in her at the time, and was not seen at autopsy. And so this question sort of haunted me.
So the simple answer to your question is I knew I was going to pursue a career in research. I had not picked a research topic, but Janice’s experienced, Janice’s death motivated me to start to ask the question, what is it about inflammation that can cause shock in her case that can kill? And the answer turned out to be cytokine storm.
And so my colleagues and I were in the very early days at Rockefeller and at the New York Hospital, Rockefeller University in the New York Hospital. We were in the very early days, large team of us, in identifying the role of cytokines that now go by the name of TNF and IL-1 and IL-6, and how these cytokine storms can contribute to overwhelming inflammation. And that’s what I’ve been studying essentially for 40 years. This past May was when Janice actually died 40 years ago. And it really has culminated in a discovery that, as you pointed out in the introduction, may lead to using electricity to stop cytokine storm instead of drugs.

Stephen Gundry:
That’s why I wanted you on the program. I’ve been interested in cytokine production since I was a transplant immunologist doing heart transplants and certainly in my practice with patients looking at leaky gut and looking at these markers like IL-1, IL-6, TNF-alpha. From my perspective, the more leaky gut we have, the more we actually activate our immune system to produce these signaling molecules.
One of the intriguing things about your book is focusing on using the vagus nerve. And believe it or not, as a general surgeon and as a heart surgeon, I was routinely cutting the vagus nerve to treat ulcers or other conditions. Or while I was up in the neck of patients, I was routinely trying to avoid cutting the vagus nerve when I was operating on carotid arteries and so forth. So I have a deep respect for the vagus nerve as a surgeon, as I’m sure you do.
So getting back to this great nerve, now your book opens with Galen’s pig experiment, which was one of the turning points in medicine. Can you tell our listeners why you chose to highlight that moment and what do you think it teaches us about scientific discovery?

Dr. Kevin Tracey:
A great deal. I have great respect for the great nerve. The name of the book actually comes from what Galen used to refer to the vagus nerve, as he called it the pneumogastric nerve, because he knew it went to the stomach and the lungs. But he also referred to it as great. And frankly, doctors and scientists for centuries… Galen of course was around the time zero, the first millennia. Galen was a Roman physician who cared for many of the Roman emperors as well as their gladiators and their animals, but he was also a scientist. And so in many ways, Galen was one of the first physician scientists. And his term, the great nerve, actually stood for centuries. For some 1,500 years or so, the vagus nerve was called either the pneumogastric nerve or simply the great nerve. And so that’s where the name of the book comes from.
The reason Galen is associated with that nerve is, one, because he began studies, anatomical studies on its path. Now he was limited in many ways. One, it was illegal and deemed unethical to study human cadavers, so he didn’t have access, at least not legally, to human anatomy. So he turned to large animals. And he could dissect baboons and pigs and sheep and cows and whatever he could get his hands on, but he could also operate on them. Unfortunately, there was no anesthesia. He did essentially like a public demonstration, like a public health announcement.
So a wealthy colleague had rented a large hall and Galen put on this show. They had a pig tied on the operating table and it was squealing away. And Galen exposed a branch of the pig’s vagus nerve, a small branch which he had discovered in the neck, which we now know today is the laryngeal nerve. And that’s the branch of the vagus nerve that goes to the voice box.
Now, back then, nerves were thought to originate in the heart, and the heart was supposed to be the source of all sort of action and activity and behavior. The brain was thought to be an organ that cooled the blood. The brain wasn’t thought to have anything to do with producing behavior. So the pig’s squealing away. Galen is showing everybody, “See this nerve? That’s part of the pneumogastric nerve, but look, it’s going over here.” He cut it and the pig was silenced. And so what I like to say is with one swoop of his knife, with one flick of his knife, Galen made two incredibly important discoveries. One, he proved that the vagus nerves, that nerves themselves were carrying the information that controls behavior, which later of course was linked back to the brain. And second, he proved that the larynx, the voice box, your Adam’s apple as we call it today, that that was the source of vocalization. So what can you learn from that? You can learn that experimentation produces knowledge, and knowledge can become embedded in human culture and change the world.

Stephen Gundry:
Now you also, in the book, you tell a fascinating story about one of your patients like Kelly Owens who really, I mean it’s a tearjerker, went from decades of suffering to living a normal life all from stimulating this vagus nerve. Can you elaborate on that? Because I think it helps people understand the power that you suggest this nerve has over what we would assume it has nothing to do with?

Dr. Kevin Tracey:
The power you’re referring to that the nerve has that was discovered in my lab in the late 1990s is the ability to inhibit, to suppress inflammation. And this came out of left field. We can talk about the experiment that led to that, but first we’ll tell you Kelly’s story.
So Kelly was a young girl who was living a normal life playing high school sports, volleyball, basketball and everything. She was very active. And she injured her knee and came home that night and her knee swelled up to the size, as she says, of a volleyball. Now, what’s important about Kelly’s story is that for her whole life she was journaling, keeping diaries, and later even blogging and posting all these stories. So all these stories are readily accessible online from her own words.
What happened was it wasn’t a sports injury that caused her knee to swell. After a complicated medical workup, Kelly received a diagnosis of Crohn’s disease, which is an inflammatory bowel disease that’s an autoimmune condition. Now like any autoimmune… Many, not any, but like many autoimmune conditions, they may start in the intestines, inflammatory bowel disease, but the inflammation can spread to other tissues. And in Kelly’s case, it spread to her joints. And she developed disabling arthritis from this, to the point that her father gave her a cane for one of her birthdays. And Kelly spent many years in and out of wheelchairs or using the cane.
She was treated with powerful immunosuppressing medications everywhere from New York to the Mayo Clinic to Hawaii and back. But as a young woman, now a school teacher, her physicians finally told her that they were out of medical options. She’d spent more than a million dollars on various medications, and they told her to get prepared to spend the rest of her life taking steroids, which of course nobody wants to do. The side effects of those are terrible as well, and immunosuppression is a big one.
Kelly saw me on Huffington Post Live talking about how the vagus nerve can inhibit inflammation and that the science that my laboratory here at the Feinstein Institute, my colleagues and I had laid out. Science, which by the way, has now been replicated by dozens, if not hundreds, of laboratories all around the world over the last 25 years.
What I said on Huffington Post Live was that I’d started a company called SetPoint Medical, and that was leading into clinical trials. Kelly called me up. I don’t remember speaking to her. She may have spoken to my office, but we advised her to look into the SetPoint clinical trials, which were going on in Europe. Somehow, and when you meet Kelly someday, you’ll understand. She talked her way into this clinical trial. She and her husband Sean sold all their earthly belongings in New Jersey and moved to Amsterdam for six months where a neurosurgeon participating in the clinical trial led by SetPoint Medical, the company I co-founded, now a California company, the neurosurgeon implanted a device which was like a cardiac pacemaker. I call it a generation 1 vagus nerve stimulator. We can talk about generation 2 later.
This pacemaker drove electrical signals into her left vagus nerve five minutes at a time, several times a day. And about two weeks later, she’s still in Amsterdam of course, she’s recovered from the surgery and she’s on her way to a doctor’s appointment. And of course there’s elevated trains in Amsterdam and Kelly was running a few minutes late. She saw the train pulling into the station and she ran up the stairs. She gets to the top of the platform and turns around like, “Where the heck’s Sean?” Well, Sean’s standing at the bottom of the stairs with tears in his eyes, tears of joy because he hadn’t seen Kelly able to run it all, never mind run up a flight of stairs in years.
Kelly went on to make a remarkable recovery. Currently, and I spoke to her recently, she currently takes no medications. Her only therapy is the vagus nerve stimulator in her left neck. And she has no signs or symptoms of inflammatory bowel disease or arthritis. You’re right, it’s a tear-jerker story. It brings tears to my eyes even now. She’s all better.

Stephen Gundry:
I like seeing miracles, what I would’ve called a miracle 30 years ago. I still get up every day and see patients six days a week because I get to see miracles like that that I wouldn’t have believed.
One of the reasons I wanted you on the program is you remember from medical school we were taught that the vagus nerve is kind of how the brain talks to the various organs and sends information downward. But subsequently, we know that for every fiber coming from the brain down to the organs, there’s actually a lot more fibers coming up from the viscera to the brain. And so you’ve taken a top-down approach and my work has been taking a bottom-up approach.
So what I want to know is, and I’ve read your research and I’ve read your book and it’s very impressive, and again, that’s why I wanted you on, I think there’s a common ground here that can you tell our listeners, okay, how did putting a pacemaker on this nerve change what was happening in the signaling in the gut, in the immune system activation in the gut from your standpoint? Can you go into that for us?

Dr. Kevin Tracey:
The discovery that we made, we today call is widely known as the inflammatory reflex. Now what’s a reflex? We’ll go by first principles. A reflex is what happens when you’re sitting on the exam table in a doctor’s office and she thumps your knee and your leg goes up and you say, “Who did that?” That’s a reflex.
The way it works is that the rubber hammer stretches the patellar tendon, which activates sensory nerves. Reflexes begin with sensory input. The sensory input to the spinal cord is relayed back to motor nerves that travel back down to the quadriceps, femoris, your thigh muscle and your leg pops up. That’s a reflex. Well, the same thing’s happening in all your organs all day long that you don’t think about. The vagus nerve is carrying reflexes to all your organs. One family of them we call the inflammatory reflex.
But let’s, again, first principles, what’s the vagus nerve? Well, as you said, it travels from the brain at about the level of your ear, down your neck and chest, and it touches all the organs you never think about all day long. But very importantly, we say the vagus nerve, but you have two, one on each side. And more importantly, in each of those two vagus nerve propers, you have 100,000 fibers. So you actually have 200,000 vagus nerves. It’s very hard to study the individual fibers in humans. It’s nearly impossible. But we can do a lot in mice and in other animals.
In mice and some brilliant work from Harvard by Steve Liberles and his team, as few as 100 or 120 fibers in a mouse regulate breathing. So you have this massive number of fibers, but the function of each fiber is highly specific. So that means if a small number of fibers can control breathing… In a mouse, there’s like 5,000, not 100,000, but that small fraction of fibers is what you need to breathe, then you’ve got thousands of other fibers doing other actions.
So in the context of inflammation, what we’ve discovered is that when inflammation occurs in your body, say in your intestines or your liver, that activates vagus nerve sensory fibers that travel up to the brain stem. And recent work from Charles Zuker’s lab at Columbia here in New York or from my own lab at the Feinstein Institute, were able to show a specific cytokine like IL-1 or TNF can activate specific bundles of vagus nerve fibers that carry the information up into the brain.
Now when it gets there like your knee-jerk, the incoming information activates an outgoing signal. And what we’ve discovered is that about a thousand fibers in humans carry signals from the brain back to the spleen where it literally shuts down the white blood cells ability to make toxic levels of cytokines. Now, it doesn’t immunosuppress. It doesn’t cause the white blood cells to become immunosuppressed. It doesn’t turn off cytokine production completely. It just lowers it. It suppresses it by 50 to 80%. So now in an inflammation situation, your white blood cells making toxic or dangerous amounts of cytokines like what happened to Janice or to Kelly Owens, these toxic amount of cytokines are reduced if we stimulate those fibers to block the release of cytokines.
The company, SetPoint Medical, has now built a device which is called an immunoregulator, and it’s specifically designed to stimulate for one minute a day in the left neck, the fibers that turn off inflammation. And what’s amazing about this is that the activation of the inflammatory reflex for one minute a day with this device that’s the size of a multivitamin in a FDA-approved breakthrough clinical trial had significant benefit in 80% of the patients after one year. So 242 patients were enrolled in the trial. The results were so successful that the FDA approved this device. Now the immunoregulator for use in treating patients with rheumatoid arthritis.
So it’s come sort of full circle from a project in the laboratory discovering the vagus nerve acting like the brakes on your car to slow down inflammation, to an FDA approved device for rheumatoid arthritis.

Stephen Gundry:
Yeah, that’s a long way around.

Dr. Kevin Tracey:
30 years.

Stephen Gundry:
So let me bring it back to something that I’ve talked about and I’ve had him on my program, Wim Hof the Iceman. We know that we can inject lipopolysaccharides, LPSs, which are dead bacterial cell walls, into human volunteers and produce septic shock even though they are dead bacteria. Exactly what you described killed your little patient years ago.
And Wim Hof, as you well know, primarily his breathing techniques can be injected with LPSs. And rather than fainting and becoming tachycardic, sits there and laughs and continues the conversation. And he’s shown in volunteers that they can be trained to also withstand the same insult.
And what I’m hearing from you, and this is all, in my humble opinion, regulated by his control of his vagus nerve. What say you?

Dr. Kevin Tracey:
So this has been studied as you know by Peter Pickers in a beautiful paper. So I met Wim Hof about four or five years before Peter Pickers did that study. And I also studied Wim Hof in a sort of an end-of-one study here at the Feinstein Institute.
What we did was, my colleague, we drew his blood and then we said, “Okay, you do your thing.” And we shut the door of the exam room and we went and got coffee or something and came back two hours later and drew his blood again. “Wim, come back in a week and we’ll tell you the results.”
So he comes back in a week and I said, “Wim, your cytokine production, how much cytokines you could make in your blood before and after the first two hours, the baseline and two hours later when we left you,” I said, “you reduced your cytokine production by about 80%.” I said, “What did you do?”
And he said, “I breathe like a mother (beep).”
And I said, “Okay.”
He said, “Are you going to publish me?”
I said, “No, we’re not going to publish you.”
He said, “Why?”
I said, “We have to do a proper study.”
And he said, “What’s a proper study?”
I said, “Well, you have to teach 10 people to do this and show that you can replicate it. And people you don’t teach, so they’re the controls. And then the first 10 have to teach the second 10 and repeat the study.” And that’s in fact… So Wim at the time was living in Amsterdam, so he collaborated with colleagues in the Netherlands and they did the study there. It would’ve cost a lot of money for me to do this study here, which I told him at the time.
So he did the study and I opened the proceedings of the National Academy of Science. I was thrilled to read the study. Now, and by the way, Wim on several podcasts has actually given me a shout-out for that little story I just told, and it’s in the book.
But Peter took it to the next level and asked the mechanism, and what he discovered was that when Wim does this breathing, which is like a tantric breathing, it’s big breaths in, big breaths out repeated 30, 40 times, breath holding for as long as possible, repeat the cycle three or four times. That was known already in what Peter proved by measuring norepinephrine levels in the blood is that induces a massive stress response.
Now, years before when I was still a trainee in neurosurgery in New York, my colleagues and I had injected Steve Lowery, and others had injected, as you said, endotoxin. But when we injected endotoxin with norepinephrine to mimic a stress response, we showed that that blocked cytokines. So it’s actually a fight or flight response.
Now if you have a flight or fight response, does that mean your vagus nerve is turned off? Absolutely not. The textbooks say that, but they’re wrong. And we know they’re wrong because of a study a year or two ago from New Zealand in which the researchers there were studying sheep. Now, all I can think of is a far-sight cartoon with the sheep jogging on a treadmill in a lab and what all the captions could be. But turns out this study was brilliant, is brilliant, and important because it’s one of the first studies to prove that during exercise, you exercise not only your sympathetic fight or flight response, but you also turn on your vagus nerve. They’re both turned on.
And in fact, the importance of turning on the vagus nerve with fight or flight, as a cardiac surgeon, you may remember this from decades ago, a Japanese study, when you stimulate the vagus nerve during sympathetic stimulation, you actually get a synergistic increase in cardiac output because you slow cardiac filling to the point that you get a more efficient expansion of the right ventricle and you get more cardiac output, you get more coronary artery blood flow.
It’s a really important question and a really important answer. Turning on fight or flight does not necessarily mean you’re turning off the vagus nerve. And turning on the vagus nerve doesn’t mean you’re turning off fight or flight. There’s much more harmony and balance in biology than on and off. It’s much more functioning in harmony and in synergy. And that’s really the story, I think, of the vagus nerve, whether it’s for inflammation or heart rate variability or all the other things it does.

Stephen Gundry:
In my practice, patients come to see me very much for why that young lady came to see you. They’re looking for options beyond drugs. About 80% of my practice is autoimmune disease. These people are on one or two or three immunosuppressants, which they realize is probably not a good thing. And in many cases, they’re not working. And you’re right, living on steroids the rest of your life is a bad idea. Bio-electronic medicine or bio-electric medicine may be one of these solutions. And so can you explain how electricity is one modality here that we’ve neglected?

Dr. Kevin Tracey:
The key to understanding bio-electronic medicine is similar to the key to understanding how you would make any other medicine. It begins with knowing the molecular mechanism of the disease.
So we can walk through an example of rheumatoid arthritis in which the purported molecular mechanism is producing too much TNF. Now you’re right, the drugs that block TNF only work about half the time, 40% of the time. So it’s not the whole story. But let’s just think about the 40% patients that it is working in. So TNF is a valid drug target in rheumatoid arthritis. If you’re a drug company, you say, “I’m going to make drugs that hit TNF specifically, and that will be what will test for safety and efficacy and then we’ll market those.” If you take a bio-electronic medicine approach, you say, “Okay, TNF is the target. Rheumatoid arthritis is the disease. Can we find neural circuits that lower or reduce TNF production in the body?” And the answer of course, we’ve talked about is, yes, we discovered vagus nerve circuits that can turn off TNF. Okay, check that box.
Now the question becomes not can we make drugs that do that, but can we make devices that control the activity of nerves. And that’s exactly what we did at SetPoint Medical. Setpoint Medical developed a device the size of a multivitamin that uses electricity, it has a rechargeable battery, to drive a current through a circuit board. The device has a little antenna in it and it can talk to the doctor’s tablet so the doctor can adjust the strength and the frequency of the treatment.
The electricity, what it does is it delivers pulses, little spikes of electric current into the vagus nerve in the neck for one minute a day. What happens, the electricity going into the vagus nerve, these spikes, it’s not traveling up and down the vagus nerve like a copper wire. These spikes are on and off, on and off, on and off. And the on and off nature of the spikes causes the vagus nerve itself to fire on its own behalf. So nerves carry action potentials, which are voltage spikes. And you can incite the nerve or induce the nerve to fire its own voltage spikes which travel up and down the nerve away from this source of stimulation or activation.
And so the answer to your question is this multivitamin sized bioelectronic device delivers the signals to turn on the brakes using the vagus nerve’s own evolutionarily conserved mechanisms that evolved over millions of years to control the magnitude of the TNF and IL-1 and IL-6 and other cytokine responses.
The real key to bioelectronic medicine in the case of rheumatoid arthritis is it’s not a completely new idea. I told you Kelly has a Gen-1 device because vagus nerve stimulation was first approved in the 1990s to treat patients with epilepsy. And then soon after that, patients with depression. There’s been follow-up studies in 250,000 patients followed for 30 years. We know that it’s safe. We know that it doesn’t have a black box warning. We know that it doesn’t cause immunosuppression. And we know that it’s a one-time expense, not a recurring annual expense of 50,000 to $100,000 a year.
As you know, some of your patients I’m sure talked to you about this. I think there should be a side effect warning on some of the biologics that bankruptcy is a potential side effect because that’s what happened to many people I’ve met. And now some of them have this immunoregulator in their neck and they don’t need to take those drugs anymore. And so there’s a lot of stories out there now, it’s not just one patient.

Stephen Gundry:
It’s great that I can have a multivitamin inserted in my neck. We see now lots of devices, consumer devices that purport to stimulate the vagus nerve, maybe the vagus nerve in the ear, devices that you wear on your neck to stimulate the vagus nerve. Where are we in that realm?

Dr. Kevin Tracey:
Buy or beware as you know is the best answer. Buy or beware. Let’s start with the scientific engineering medical physiological facts. There’s only two ways to specifically stimulate the vagus nerve. The first is, as we’ve been talking about, to put a stimulating electrode directly on the nerve. And there’s several FDA-approved devices to do that and they’ve all been subjected to FDA regulatory scrutiny. They’ve all been subjected to large randomized, well-controlled, replicated clinical trials. That’s the gold standard way to know that you have specifically stimulated the vagus nerve. You have a device implanted usually in the neck.
The second way is experimental. We’ve done it here in my lab. Several other research centers have done it. You can use a technique called focused ultrasound, and that will channel the ultrasound energy through the tissues and you can focus it, if you will, on the vagus nerve and stimulate the vagus nerve in the liver for instance, where we’ve done some work to show that that can actually cause weight loss and correct the hyperglycemia and hypoinsulinemia in models of obesity and type 2 diabetes. And there’s clinical trials progressing in that space, which are fascinating and we could talk about that.
Then there’s this whole universe of using transcutaneous electrical nerve stimulation, which is essentially putting electrical devices on the skin. Some people put it on their neck, some people put it on their ear. There is zero, none, nada evidence that those are vagus nerve stimulators. There’s lots of evidence that electrical current on the skin travels across the skin, it travels across the muscles and subcutaneous and fat tissues under the skin. There’s no evidence that it can travel through these tissues, through the sternocleidomastoid muscle, through the fat to target the vagus nerve inside the carotid sheath in the neck, for instance.
Now where it gets very confusing is that the FDA has authorized some devices as vagus nerve stimulators, which are essentially TENS units despite what I just said. And so, fine, you can say it’s a nomenclature issue. The problem with that is it does create some confusion.
Now, if you’re considering sort of a do-it-yourself stimulation with a TENS unit, I think there’s several factors to consider. First, check with your doctor. Is it safe? Second, is it FDA-approved? If it’s FDA-approved, what condition is it FDA-approved for? Is it approved for your condition or for a different condition? Third, and in this day and age, this is incredibly complicated and confusing. What does the clinical trial data say about the use that you want to use it for? How many patients were in the clinical trials? Were they appropriately randomized? Were the trials appropriately controlled? Are the statistics correct? Are the assumptions and follow-up correct and proper?
When you scratch the surface of that looking for instance at recommendations to use a TENS unit in your ear, there is only two clinical indications that have been subjected to that that passed that muster with large clinical trials, well controlled, well randomized. And they’re both with the same device. It’s a European device used to be manufactured by a company called CervoMed. I’m not sure it’s available anymore. And they showed that stimulating the ear, the cartilage of the ear, which has a branch, a sensory branch of the vagus nerve, that that actually had clinically significant benefit in some patients with epilepsy, about half of them. And it had clinically significant benefit in helping people with sleep disorders. The interesting thing there was that the beneficial effect on the sleep disorder seemed to persist for many weeks after they stop stimulating.
All the other potential indications for these devices are either very small clinical trials. Some of which I’ve done, my colleagues and I have done. 20 patients, 15 patients. And they’re interesting, right? That’s how you start in science and medicine. You start with a pilot trial and then you move to a replication trial and a larger trial and add more controls. Most, if not all, of the recommendations by people selling things for their vagus nerve, not what they call non-invasive vagus nerve devices. Nearly all of them don’t pass that muster that you and I would consider clinically rigorous.

Stephen Gundry:
Final question on that subject, since Wim Hof and his tantric breathing does work, are there any take-homes from this discussion today for somebody who wants to use their vagus nerve to reduce inflammation? Is it meditation, breathing techniques, breath-holding?

Dr. Kevin Tracey:
The advice you give your patients probably every day and the same advice grandma gave you and me, right? Eat a balanced diet, get enough sleep, pay attention to your exercise routine, and try and exercise regularly. Try to stay socially and cognitively connected to friends, family and community, giving back something when you can. Try to avoid excess stress in your life. If meditation helps you do that and reduce anxiety, great. If there are other cognitive behavioral therapies that help you do that, great. Practice those.
At the end of the day, what’s so remarkable about all of those recommendations and a few more is that they all are associated in one way or another with reducing resting heart rate. And as you know, and most people nowadays seem to know after billions of web impressions, a slower heart rate tends to be associated with improved heart rate variability. And that is one imperfect, but one way to get a sense of a healthy vagus nerve, if you will.
Now we’ve seen in patients with autoimmune disease and long COVID that their vagus nerves are damaged and heart rate variability can be impaired and resting heart rate tends to be higher. Does that mean if you exercise more and do some of these things that are recommended to “stimulate” your vagus nerve, that they’ll be fixed? Well, no, not necessarily. I mean, seriously, if a rheumatoid arthritis patient could do a few extra sit-ups to take away their pain and suffering, they would do it. It’s not that simple. If the vagus nerve is damaged, for instance, it might require a device therapy. It might require an immunoregulator. It might require something else.
That being said, for people who are generally healthy, presumably you, hopefully me, and we want to optimize our health, those basic health practices are all good things. I do meditate. I do try to watch my diet. I do try to exercise regularly. I do try to get enough sleep. I do try to use my brain and stay socially engaged and active. And a couple times a week I put the shower on full cold because the evidence is pretty clear that my doctor said it’s okay for me to put the shower on full cold. You have to check. But the evidence is pretty clear that that cold shock activates fight or flight, which we already talked about. And that fight or flight is anti-inflammatory.
And if you stay in the cold, which I’ve trained myself to do, you actually find it, first of all, I noticed that it’s still uncomfortable, but I don’t mind it so much. It’s some sort of meditation, and Wim Hof does talk about that. When he’s in the cold, he finds it an ideal time when he comes out to meditate. But in addition, if you stay in the cold long enough to notice that you’re calming down or observing, it’s almost like observing someone else in the cold, if you check your pulse, you’ll find your heart rate has slowed. And at that point now I’ve done both, right? I’ve stimulated fight-or-flight and rest and digest.
So yep, it’s what grandma and your primary care physician tells you to do, is I think is the best advice for your healthy vagus nerve.

Stephen Gundry:
Yeah, you make a good point. My mentor at the NIH, who was the head of heart surgery at the NIH, Andrew G. Morrow, actually always used to quip that we only have so many heartbeats in our lifetime. And once you use them up, that’s it. So that anything you can do to preserve what you’ve got, and again, that’s exactly what you’re saying.

Dr. Kevin Tracey:
The Framingham heart study proved him correct, right?

Stephen Gundry:
Yeah. Yeah.

Dr. Kevin Tracey:
So the only single known predictor of the longevity of a population is resting heart rate. The slower, the better. He was right.

Stephen Gundry:
We have an audience question. This is from Glitterbug12X on YouTube. “Can vagus nerve stimulation help with tinnitus or tinnitus? My dad has really bad tinnitus and has tried various treatments to no avail. Got any thoughts?”

Dr. Kevin Tracey:
My thoughts are maybe, for the following reason. But before I get to maybe, first let me tell you, maybe also means nobody knows the answer. There is not a clinical trial you can point to of a well controlled study using vagus nerve stimulation to treat tinnitus. However, if your father’s physician gives permission and if your father doesn’t mind trying a ear stimulating device, for instance, which may or may not stimulate a branch of the vagus nerve to the ear, it is possible that some forms of tinnitus are caused by excessive inflammation in the middle ear. So it’s the theoretically possible based on evidence from many clinical studies. All small and not all well controlled, but many clinical studies have pointed to the possibility that a TENS unit applied to the left ear may in fact reduce inflammation in some conditions.
We’ve seen that in rheumatoid arthritis, we’ve seen it in lupus arthritis. My colleague Ben San recently reported in pediatric Crohn’s disease some benefit in his studies. So we don’t have all the answers. Can’t make it as a medical recommendation, but it is something to consider if it’s possible for him to try it.

Stephen Gundry:
Well, that’s a good summary. We were talking off-camera. I’m not aware that there’s any valid study. Yeah, so we’ll leave it at that, but it’s a great question and probably needs more looking into.
Well, Dr. Tracey, it’s great meeting you and coming on the show. I think this is an area that my listeners are not aware of, and that’s why I wanted to have you here. So thanks again. And good luck with the book, The Great Nerve. Great title.

Dr. Kevin Tracey:
Thank you so much, Dr. Gundry, for having me on. And thanks for letting me talk about the book with you. I really appreciate it.

Stephen Gundry:
Now it’s time for the review of the week. The review of the week comes from @Ferriana on YouTube. They said, “I love you, Doctor. Heart emoji. Your knowledge is mind-blowing, and you know what? It’s actually always confirming my gut feeling, intuition. I’m so grateful for your advice. Also, you look great. Thumbs up emoji. And I trust you. Thanks.”
Well, thanks very much, Ferriana. You know, I try to give you the information that I’ve learned taking care of patients six days a week for the last 30 years. And as I say, I report and you decide. I’m glad it’s working out for you. Thanks very much.

Speaker 1:
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