Understanding the “Great” Vagus Nerve with Dr. Kevin Tracey [Episode #992]

 

This Week’s Episode Special Guest: Kevin Tracey

In this episode Dr. Kevin J. Tracy discusses his groundbreaking work on the vagus nerve, its role in inflammation, and it’s connection to autoimmune diseases. He shares personal stories that shaped his career and emphasizes the importance of understanding the vagus nerve for health and wellness. The discussion also covers lifestyle measures, meditation, and the relationship between the vagus nerve and heart health, highlighting the need for further research in these areas. In this conversation, Dr. Kevin Tracey discusses the significance of the vagus nerve in health and wellness, exploring its role in vagal tone, bioelectric medicine, and its implications for autoimmune conditions and depression. He emphasizes the importance of a holistic approach to health, the potential of vagus nerve stimulation as a treatment option, and the reflexive nature of our bodily functions. The discussion also highlights personal experiences and insights that drive the pursuit of medical advancements.

About Kevin Tracey

Kevin Tracey, MD, is a best-selling author,  neurosurgeon, scientist, entrepreneur, and leader in the fields of vagus nerve stimulation and inflammation. His new book  THE GREAT NERVE (May 13, 2025 Avery) reveals the vagus nerve is the body’s most powerful—yet underutilized—healing pathway, capable of reversing devastating illnesses without drugs. Dr. Tracey and his colleagues in his lab at the Feinstein Institutes discovered the molecular and neural mechanism for the reflexive control of inflammation, now termed the inflammatory reflex. He is a prolific inventor, with more than 120 United States patents. As measured by and reported in the scientific journal PLOS One, Dr. Tracey is one of the most highly cited living scientists in the world. Dr. Tracey was trained in neurosurgery at the New York Hospital-Cornell University Medical Center and was a guest investigator at Rockefeller University before moving to the Feinstein Institutes. There he directs the Laboratory of Biomedical Science and was appointed President and CEO in 2005.

 

Episode Sponsors:

LMNT:

OFFER: Right now, for my listeners LMNT is offering a free sample pack with any LMNT drink mix purchase at DrinkLMNT.com/FEELGOOD. That’s 8 single serving packets FREE with any LMNT any LMNT drink mix purchase.  This deal is only available through my link so. Also try the new LMNT Sparkling — a bold, 16-ounce can of sparkling electrolyte water.

USE LINK: DrinkLMNT.com/FEELGOOD

 

FATTY15

OFFER: Fatty15 is on a mission to replenish your C15 levels and restore your long-term health. You can get an additional 15% off their 90-day subscription Starter Kit by going to fatty15.com/KIMBERLY and using code KIMBERLY at checkout.

USE LINK: fatty15.com/KIMBERLY

Guest Resources 

Book: THE GREAT NERVE 

Website:   The Great Nerve: The New Science of the Vagus Nerve and How to Harness Its Healing Reflexes

 

Episode Chapters

Chapters

00:00 Introduction to Dr. Kevin J. Tracy and His Work
04:05 The Impact of Personal Loss on Purpose
07:10 Understanding the Vagus Nerve and Inflammation
09:58 Exploring Autoimmune Diseases and Vagus Nerve Connection
15:07 Lifestyle Measures for a Healthy Vagus Nerve
19:58 Meditation, Heart Health, and Vagus Nerve Dynamics
26:11 Understanding Vagal Tone and Health Span
28:02 Innovations in Bioelectric Medicine
30:04 Vagus Nerve Stimulation for Autoimmune Conditions
35:02 Exploring the Connection Between Vagus Nerve and Depression
38:57 The Reflex Basis of Health and Well-being
44:05 Practical Applications and Personal Insights

 

[RESOURCES / INFORMATION]

SOLLUNA PRODUCT LINKS

• Glowing Greens Powder™
• Feel Good SBO Probiotics
• Feel Good Detoxy
• Feel Good Digestive Enzymes
• Feel Good Starter Kit
• Feel Good Skincare

KIMBERLY’S BOOKS

• Chilla Gorilla & Lanky Lemur Journey to the Heart
• The Beauty Detox Solution
• Beauty Detox Foods
• Beauty Detox Power
• Radical Beauty
• Recipes For Your Perfectly Imperfect Life
• You Are More Than You Think You Are 

OTHER PODCASTS YOU MAY ENJOY!

• Wellness Insights: How to Listen to Your Body for Nutritional Guidance [Episode 878]
• How the Power Foods Diet helps with Weight Loss with Dr. Neal Barnard EP. 877
• How Not to Age with New York Times best-selling author Dr. Michael Greger [Episode #873]
• How to eat to reduce anxiety with Harvard nutritional psychiatrist Dr. Uma Naidoo [Episode #867]

 

Powered and Distributed by: PodcastOne

Transcript: 

Solluna By Kimberly Snyder (00:00.972)
Hi everyone. Welcome back to our Monday interview show. I am so excited for our very special guest here with us today. His name is Dr. Kevin J. Tracy, and he’s a neurosurgeon, scientist, entrepreneur, and leader in the fields of vagus nerve stimulation and inflammation. He is one of the most highly cited living scientists in the world, and he has a fascinating new book out, which I read.

cover to cover called The Great Nerve, the new science of the vagus nerve and how to harness its healing reflexes. Dr. Kevin, I will call you Kevin from now on, but just to start off, Dr. Kevin, thank you so much for being here with us today.

Kevin Tracey (00:42.856)
Ha ha ha ha.

Kevin Tracey (00:48.042)
Well, thank you for having me on. I’m really looking forward to chatting all about the great nerve.

Solluna By Kimberly Snyder (00:53.774)
So it’s really fascinating, the subject matter. I think some of us have heard about the Vegas nerve and increasing popularity, whether in the media, social media. There’s so much I want to get into. But first I want to say, Kevin, that, wow, I wasn’t… Sometimes you get into these scientific books and research books and it can be a little bit dry.

But what really surprised me in a positive way about your book was the humanness that you brought to the book. And it was very readable and it was very accessible for a lay person who’s not a scientist to really grasp the information. And right away at the beginning, your book made me cry when you talked about the passing of your mother when you were five. And my youngest is four right now.

I was just thinking how, you know, for a child to lose their mother at such a young age, must have been so just, you your world gets turned upside down. So you go into that story, but also because her condition was related to her brain and that you became a scientist, there was a positive outcome. really, sounded like it really influenced your purpose and the direction of your life.

Kevin Tracey (02:17.994)
It did. You know, the, the idea of, of five year olds, grappling with what reality is and then going through a loss today, modern psychologists and psychiatrists, they look at these events as having long-term trauma to some. And it is a trauma that occurs when you’re five years old and lose your mother. But

You can come out of trauma 60 years later, 63 years later and look back and have an understanding to it. she died of a brain tumor very suddenly. And now here I am, a neurosurgeon trying to invent therapies, trying to invent things to help other people not have to lose their mother or their other. And can you connect the dots and say that?

led to this? Of course not. You can’t. But you can gain an understanding that children, even very young children, are formulating a view of the world that oftentimes I think is much more profound or

Kevin Tracey (03:37.502)
deep, if you will, or intuitive than adults understand. it’s not like it’s easy to study this in the groups of five-year-old children. You’re making assumptions about what they’re thinking and feeling because they don’t have the complete capacity of language and vocabulary that develops over many, many years later. But I’m strongly convinced that what happened to me

Solluna By Kimberly Snyder (03:44.002)
Yes.

Kevin Tracey (04:05.798)
at five influenced the entire course of my life. And I try to tell that story in this book.

Solluna By Kimberly Snyder (04:11.02)
You know, it’s amazing sometimes, you know, people are searching for their why, or they’re looking for, you know, what is my purpose? And it was so clear from the beginning and it, you tell that story upfront. And then there’s other, another story that has a mother made me cry about the 11 month old Janice who got burned. And you’re talking about some of your theories about inflammation and you know, why this child passed away.

And it’s just so clear that your drive, Doctor, is to really understand and to alleviate suffering. And it really comes across in your book and the way you write and your work. And so I just want to really acknowledge that, that, you know, there’s a lot of depth of science, but there’s also so much heart and so much love in the way that you’re writing. And it just really felt and it really touched me when I was reading this book.

Kevin Tracey (05:06.9)
Well, thank you. Your compliment means a great deal, coming especially from you. So thank you sincerely. In my journey as a neurosurgeon scientist for the past 40 years, give or take, I have come across many others who, like me, were touched, if not by a family member, but by a patient, and found in the inability to help that patient,

the drive, the motivation, the meaning, as you say, to pursue a cure. And that story resonates across not only my own experience with friends and colleagues and people I’ve met, but that story resonates across the centuries in the history of medicine. And the idea that one individual suffers and motivates another to find

a cure or to pursue a cure or to pursue an answer. That story recurs over and over again in the history of medicine. And if you think about it, what does it say? It says that one person, one person suffering and another trying to alleviate can change the course of the world. And I think the more that message needs to be internalized more and more by your listeners and listeners everywhere to know that

what they decide to do and how they decide to react makes a difference not only in their own personal lives and their family’s lives, but everyone can change the world for the better. And that’s very inspiring to me.

Solluna By Kimberly Snyder (06:44.396)
Yes, it’s the concept of oneness. know, Dr. Howe, we’re all connected and what happens to us, we can, you know, change our perspective and be motivated to do good, to shift things. And so it was very, very motivational, very inspiring. And then as you continued your work, you came to focus back to the great nerve on the vagus nerve. Can you tell us a little bit about…

just briefly why the Vegas nerve and if people are listening to this and they’re like, I’ve heard of it, but I don’t really exactly know what it is and why it’s important. Of course, there’s a whole book about why it’s important, but just in a nutshell, just to give us a little bit of an intro before we dive deeper.

Kevin Tracey (07:26.91)
Sure. So by way of intro, you made reference to Janice, the little girl that I cared for in the burn unit at the New York hospital. And she died in my arms of overwhelming inflammation. So what is inflammation and what does that have to do with the vagus nerve? Well, inflammation is what happens when the body reacts to either an injury or an infection. And you’ve seen it if you sprain your ankle or your knee, it turns red, it swells, it hurts.

And you’ve seen it if you’ve had an infected pimple or an infected cut on your skin, it turns red and it swells and it’s painful and it gets warm. That’s what inflammation is. And that’s a healthy, good response to injury and infection. It helps heal the wound and clear out the infection. that type of inflammation we need. But the problem is, that inflammation, if it’s not well controlled, if it…

doesn’t stop, if it spreads beyond the cut or beyond the local area of injury that occurs, if it spreads into the bloodstream or into the organs like the lungs and the heart and the kidney, inflammation can kill. And so the question that I confronted after Janice died was why did her body fail to control the inflammation that was occurring and why most people walk around

Solluna By Kimberly Snyder (08:40.215)
Yeah.

Kevin Tracey (08:56.648)
don’t have too much inflammation. And the very surprising answer that my colleagues and I discovered in the mid 1990s is that the brain controls how much inflammation you have in your body. And it does this by sending signals to your immune system, like the brakes on your car, slow down, slow the inflammation and prevent the inflammation from causing

Solluna By Kimberly Snyder (09:11.96)
Hmm.

Kevin Tracey (09:26.43)
damage to your normal organs. And the brake lines in your car run essentially.

to the wheels of your car to stop your car. The brakes on your immune system run from your brain through a nerve called the vagus nerve, which holds the key to stopping inflammation. And that simple sentence, how does the vagus nerve hold the key to stopping inflammation is something that I’ve committed the last 25 or 30 years of my life to studying.

Solluna By Kimberly Snyder (09:44.312)
Hmm.

Solluna By Kimberly Snyder (09:58.892)
It’s really interesting, doctor, because there’s so much autoimmune and there’s so many conditions and we hear a lot about changing your diet or taking medications and you’re talking about this bioelectric therapies and tell us about how this approach is kind of going a little bit further back than some of these other approaches to inflammation.

Kevin Tracey (10:24.564)
So you mentioned earlier, as we were warming up that many of your listeners are women and autoimmune disease is a disease that occurs much more in women than in men for reasons that aren’t well understood. But an autoimmune disease are diseases like lupus or rheumatoid arthritis or inflammatory bowel disease, multiple sclerosis. These diseases are conditions where there’s too much inflammation.

Solluna By Kimberly Snyder (10:37.742)
Mm.

Kevin Tracey (10:54.558)
So the question that we’ve been pursuing for years is if we know that the breaks on inflammation travel in the vagus nerve, if the vagus nerve is carrying signals from the brain to stop too much inflammation, can we use that information to develop therapies for diseases like rheumatoid arthritis? But in order to do that, we had to learn a great deal more. you mentioned…

The vagus nerve has the great nerve and we call it the vagus nerve, but you actually have two of them. You have one on each side, like two thumbs or two kidneys. And you actually have inside of each of these vagus nerves, you actually have a hundred thousand fibers. So it’s fair to say that all of us have about 200,000 vagus nerves. they run from about the level of your ear, deep inside your brain down.

Solluna By Kimberly Snyder (11:29.165)
Mm-hmm.

Solluna By Kimberly Snyder (11:44.61)
Wow.

Kevin Tracey (11:51.88)
your neck on both sides, across your chest and into your abdomen. And what these vagus nerve fibers do is carry information back and forth from your body’s organs to your brain and back. And this information is absolutely crucial to maintaining a balanced homeostasis is called, a balanced output of your organs that keep you in a healthy range. In other words,

The vagus nerve is carrying back and forth from your brain to your body, all of the information necessary to keep you healthy so that you don’t have to think about it.

Solluna By Kimberly Snyder (12:29.914)
Mm-hmm. So what is throwing off the vagus nerve for so many people? Why are these therapies required and is it happening more often in the modern world versus just being able to maintain homeostasis naturally?

Kevin Tracey (12:46.512)
All, sorry, all the answers to that question are not in yet, but there’ve been some dramatic examples that have taught us quite a bit. So for instance, during the COVID pandemic, several studies discovered that the virus itself could infect the vagus nerve, and this was found at autopsy in some victims of COVID. And when…

Solluna By Kimberly Snyder (13:07.81)
Mmm.

Kevin Tracey (13:14.41)
when the investigators looked at the vagus nerve, they found evidence that the virus was in the nerve. And in other patients, there was evidence that inflammation caused presumably either directly by the virus or by the body’s reaction to the virus, that the inflammation had settled in the vagus nerve and damaged it. Now, if you have damage in your vagus nerve, that would be like someone cutting the brake lines on your car.

and the vagus nerve now is no longer going to be able to slow down the inflammation. And if the inflammation keeps accelerating, now what happens, it accumulates in organs and can cause permanent damage, as I said before, to various organs, whether it’s the kidneys or the heart or the lungs or the brain even. So this was a key insight that the vagus nerve can sometimes be damaged in some patients.

Solluna By Kimberly Snyder (14:04.919)
Right.

Kevin Tracey (14:13.128)
Very importantly, we and others have begun to ask the question, is it possible that damage to the vagus nerve, like damage to the brake lines in your car, is actually occurring in autoimmune diseases as well? And there is some evidence that that is occurring. In other words, people at risk, relatives at risk for autoimmune disease,

often have evidence of impaired vagus nerve signaling to the heart called decreased vagal tone. And this can occur before they have any evidence of the disease itself. So the question is, can damage to the vagus nerve actually be one of the reasons that we’re seeing increasing incidence of some of these autoimmune diseases? We don’t know for sure, but it’s definitely possible.

Solluna By Kimberly Snyder (15:07.694)
So is it kind of like the chicken or the egg? Is it the diseases are damaging the vagus nerve or potentially damage to the vagus nerve is one of the reasons that there’s a proliferation of the autoimmune condition?

Kevin Tracey (15:20.168)
Yes or both. Yes or both. Yes, it is an important research question and there’s evidence to support both sides of that equation. Chicken and egg.

Solluna By Kimberly Snyder (15:30.572)
Right. And you know, doctor, in the latter part of your book, I love how you talk about meditation, which is a very big part of our community. You had an experience with the Dalai Lama, and you talk about cold therapy, breath work, we have a mutual friend Wim Hof. You didn’t mention diet as much or you don’t focus on it as much in the book. it based on all the research and what you’ve seen with our lifestyle measures that we can control?

does that have quite a, you know, increases our chances of maintaining a healthy vagal nerve, vagus nerve, you know, barring, of course, if we get COVID or there’s some sort of infection in the vagus nerve, but just on a more general everyday basis, these lifestyle measures can help.

Kevin Tracey (16:17.438)
I think it’s really important to answer this question in the context of some more clear definitions. So back to the basics, we have 200,000 vagus nerve fibers, and each of them has been selected by millions of years of evolution to have a specific job. So a few fibers, maybe a few hundred or maybe one or 2,000 at most, go to the heart and slow your heartbeat.

A few hundred or a few thousand go to your lungs and participate in every breath you take. A few hundred, probably not a few thousand, go to your pancreas and control your insulin. Now, the way the nervous system is organized, each individual nerve fiber controls a specific function. each of those functions can operate independently of all the other nerve fibers.

So for instance, most people, most of us can walk and chew gum at the same time because the nerves that control our walking are different than the nerves that control our chewing. When you apply that basic obvious fact to the vagus nerve, you have to ask a really important question. When someone says to me, I want to do this, that, or the other thing to my vagus nerve, I say, really, which one?

Solluna By Kimberly Snyder (17:42.062)
Mmm.

Kevin Tracey (17:42.184)
Which of the 200,000 fibers do you want to stimulate or inhibit? So for instance, there’s some commonly talked about advice in the billions of web impressions and social media postings about the vagus nerve that chanting or humming stimulates your vagus nerve and that this is good for your overall health. And as I review in detail in the book,

there is a grain of truth to that because a few hundred fibers of the 200,000 go to your voice box. technically, you’re larynx. So technically when you hum or chant, you are stimulating those few fibers of the 200,000. Does that mean you’re also stimulating the fibers that can control your immune system? And does that mean you’re stimulating the fibers like

Solluna By Kimberly Snyder (18:19.118)
Mmm.

Kevin Tracey (18:39.85)
the brakes of your car on your inflammation? Not necessarily. I mean, you can walk and chew gum at the same time because different fibers have different activities. So I tell that story because each of the chapters at the end of the book, in part three of the book, addressing these recommendations and advice given by so many sources on the web.

Each of those has to be considered for scientific validity and reproducibility and truthfulness versus exaggeration of claims beyond what we really understand. So does humming stimulate your vagus nerve? Yes, it stimulates the vagus nerve fibers that go to your larynx. Do we know that humming, because of that is decreasing your inflammation through the vagus nerve? No, we don’t. Do we know that

Stimulating those fibers to your voice box also stimulates vagus nerve fibers that have a role in preventing depression or anxiety. No, we don’t. these are important questions and they can be studied and addressed. And if people like to hum and it makes them feel better, then we should encourage that.

Solluna By Kimberly Snyder (19:58.05)
Well, I love the openness as a scientist doctor where you’re not just shutting something down but saying, hey, you maybe we don’t know more research is needed. You use these two words in the beginning of the book that really stood out to me when you’re describing the great nerve, mysterious and beautiful. When you’re talking about the vagus nerve, there’s mystery around it. There’s a lot of things we don’t know yet. And when you get to that section of the book where you’re talking about meditation, and there are thousands of research papers about

different benefits of meditation for different systems of the body. And I love that you as a scientist are also a meditator.

Kevin Tracey (20:35.218)
Meditation is widely studied across imaging studies, very sophisticated brain mapping using fMRI and PET scan and other brain imaging techniques have studied meditators ranging from monks to extreme, to amateur meditators, to highly trained meditators. And what’s interesting is that meditation does influence brain activity. And what’s interesting is that

Meditation does activate regions of the brain that are implicated in all kinds of mental states. As a scientist, as a researcher, it sort of stops there, however, because depending on the meditative practice and depending on who the meditator is and depending on what other activity there is going on in the meditator’s brain before meditation begins,

you get different answers or explanations as to why meditation could be beneficial to some, but not beneficial to all in terms of reducing anxiety and depression. So for me, I enjoy meditation. I think for me, it’s very interesting to observe myself meditating, if you will, and to watch the state of my mind as I meditate. I find that fascinating.

But I don’t think it’s fair when anyone claims cause and effect explanations of how meditation works. It’s an area of active research and much more needs to be done.

Solluna By Kimberly Snyder (22:18.72)
Yeah, well said. Well said. But it really does add a holistic, you know, I just, love that section of the book. And you talked about meeting the Dalai Lama as well was really cool. One thing I was going to say, when you talked about the relationship with the heart, it’s really interesting to me, Dr. My last book was, we did some, we did a meditation study actually in terms of

heart coherence and just measuring the patterns of HRV instead of just the numbers, getting those nice smooth sine waves. And so could you talk a little bit about how the heart and the vagus nerve are related? You said that some parts can go to the heart, obviously with 200,000 nerves running through it, not all, but there is a relationship.

Kevin Tracey (23:11.25)
Yes, so of those 200,000 fibers, some number of them, several hundred or several thousand go to the heart. And the vagus nerve endings from the brain to the heart stop in two different places. The sinoatrial node, which is the pacemaker and sets the resting heart rate, if you will. And the AV node, which is involved in the conduction of the signals from the atriums of the heart to the ventricles of

And so when the vagus nerve is sending signals to the heart, it tends to slow the heart down. And what does that mean? It means that the time between the first heartbeat, heartbeat one, and the next heartbeat, heartbeat two, is prolonged. Now, when the vagus nerve is firing frequently, you’re going to see…

Solluna By Kimberly Snyder (23:58.861)
Mmm.

Kevin Tracey (24:09.008)
more variability between the time of the individual heartbeats measured in milliseconds. And if you subject those individual heartbeats to statistical analysis, things like Fourier transformations, you come up with what’s called heart rate variability assessments. So the more your vagus nerve is firing, the more variability there will be between the individual times

in the individual heartbeats, the instantaneous heart rates. So that is all fairly well, that’s fairly non-controversial. Where it gets complicated is that there are many, many different statistical algorithms used to map out instantaneous heart rates as a function of time, as a function of

of frequency and in actually in multiple dimensions after being subjected to Fourier transformation. And so there’s no consensus on the analysis of these data. So there are wearables and I won’t name any, but the wearables use different algorithms to assess the different heart rate variability metrics.

Solluna By Kimberly Snyder (25:08.854)
Great.

Solluna By Kimberly Snyder (25:27.063)
Yes.

Solluna By Kimberly Snyder (25:32.088)
Yes, I am mad. That’s great. Mad as I’m tired.

Kevin Tracey (25:37.768)
So now you quickly look online and you see, here’s a graph of heart rate variability by age or by sex or by activity. And you end up with the potential for a great deal of confusion. what I found most interesting perhaps in this is that because the active vagus nerve tends to slow resting heart rate, the slower resting heart rate

Solluna By Kimberly Snyder (25:52.481)
Hmm.

Kevin Tracey (26:07.188)
tends to correlate with longer health span and longer lifespan on a population basis. So it’s a good thing to be aerobically fit with a low resting heart rate. Once again, we’re back to the advice grandma gives you or your primary care physician.

Solluna By Kimberly Snyder (26:11.958)
Right.

Solluna By Kimberly Snyder (26:25.371)
Very simple basics.

Kevin Tracey (26:28.786)
Now, means that you have a, that means with a slow resting heart rate and perhaps a high heart rate variability, that means you have high vagal tone. Once again, that’s a good thing to be associated with a longer health span. Does that mean that the vagus nerve is giving you the longer health span? No, it doesn’t. There’s too many other variables in life based on diet and exercise and getting enough sleep and.

having important social connections and finding your meaning. All of these things together, the holistic approach you have referred to are associated with better health and longer health span. But to say that because you have high heart rate variability and higher vagus tone, vagal tone is giving you these things, no, we haven’t proved cause and effect. There are people studying this, but proving cause and effect.

is still open question as I try to explain in the book.

Solluna By Kimberly Snyder (27:33.582)
Mm-hmm. Yeah, you get into some, back to the bioelectric medicine, which is really fascinating. And we’ve heard about, you know, pacemakers, of course, but there’s a part where you talk about something as little as a pill that can help to stimulate your vagus nerve to help reduce inflammation, to do what it’s supposed to do. Is this getting more common, doctor? Is this a potential aid for many people that are struggling with

various levels of autoimmune and inflammation and haven’t tried this. They’ve tried other things, other lifestyle changes and not really seeing an improvement yet.

Kevin Tracey (28:13.5)
Yes, it is. And you just made an incredibly important point, which I want to repeat. These lifestyle changes that include diet, exercise, getting enough sleep, and a holistic approach, that’s all great advice for a general healthy population. But somebody suffering from a severe condition like rheumatoid arthritis, doing more pushups,

Solluna By Kimberly Snyder (28:34.498)
Mm-hmm.

Kevin Tracey (28:40.826)
or eating a better diet may have absolutely no benefit to that patient. Maybe their vagus nerve is damaged. Maybe there’s some other condition in their body that, you I hate to hear people talk to patients who are suffering from a serious condition and be told, you should do this and you should do that and you’ll get all better. Cause it’s not necessarily the case. Sometimes you need advanced medical therapy.

to solve a serious condition like rheumatoid arthritis. And so you refer to the small vitamin, multivitamin-sized pill-shaped device that has now been implanted in 242 patients in the United States as part of a FDA-approved trial by a company I co-founded many years ago called SetPoint Medical. And what that device does is it’s implanted on the vagus nerve, deep in the neck.

Once it’s implanted through a one inch or one and a half inch incision in the left neck, you can’t see it anymore. It’s under the strap muscles in your neck. And that device is a computer chip and an antenna and a lead and a battery, a fully rechargeable battery. And it sits on your vagus nerve and it activates for one minute a day the fibers that turn off inflammation in your body. And what that…

Solluna By Kimberly Snyder (30:04.834)
Wow.

Kevin Tracey (30:05.744)
It’s amazing actually what we’ve seen this do now in patients with serious rheumatoid arthritis. Now let me repeat that. These are patients who have tried the most powerful immunosuppressing medications available to treat their rheumatoid arthritis and these medications failed to help them. Some people say they failed the medications. The patients don’t fail anything. The medications failed the patients. So now these patients have

persisting arthritis. Many of these women can’t button their blouse without the assistance of someone else. Some of them can’t pick up a pencil. Some of them can’t care for their children. It affects men too, but it is predominantly women. And what happens now is in these women that were eligible for the trial,

Solluna By Kimberly Snyder (30:36.428)
Bye.

Solluna By Kimberly Snyder (30:48.088)
Yeah.

Kevin Tracey (31:00.99)
The implant was put on their vagus nerve and many of them, not all, but many of them had significant improvement. In fact, the study achieved its statistically significant primary endpoint. And so as you and I are speaking now, the FDA is reviewing some 18,000 pages of data and the hope, I don’t know for sure. I’m not an insider in the company anymore. So I don’t know what’s gonna happen, but my hope is that the FDA approves the use of this device.

Solluna By Kimberly Snyder (31:15.436)
Wow.

Kevin Tracey (31:30.622)
to treat rheumatoid arthritis in the United States in people who are currently not deriving benefit from all the other available medications. This would be a game changer.

Solluna By Kimberly Snyder (31:40.782)
So they could actually, again in goosebumps, if they got this device it could potentially mean they don’t have to take medication that’s not even helping them anyway.

Kevin Tracey (31:50.858)
Yes, in some cases. So I have met several patients from these clinical trials, clinical trials done either in Europe or the United States. And I’ve met several patients who have told me that they have no more signs and symptoms of their rheumatoid arthritis and they don’t take any medication. Now that’s not all the patients. It’s really important to say this will, there’s no such thing as a cure-all. In medicine,

In the history of medicine, you see three groups of patients typically, and that’s what we’re seeing right now with this device implanted on the vagus nerve. We’re seeing some patients, like you said, whose signs and symptoms resolve and they don’t even need medication anymore. And that’s amazing to witness that. Then there’s a second group of patients who, although they feel better, they’re still taking medications, although many of them are taking

lesser doses of their medication. And then the third group are patients who just don’t derive any significant benefit from the treatment. And we’re not sure why. We don’t know what distinguishes between the three groups, those who are in remission and those who are in partial remission and those who don’t have any benefit, but we’re still early in this journey and we’ll keep learning about that.

Solluna By Kimberly Snyder (33:18.892)
Yeah, it’s early in the journey, but it’s exciting to know that there’s something that can promote the body, working how it’s meant to work instead of having to just rely on pharmaceuticals, like what you said, which don’t always, they’re not always effective in every case.

Kevin Tracey (33:37.768)
But right now, some of these drugs that cost $100,000 a year and are invasive, they have to be injected, and they have black box warnings. As you say, they have serious, dangerous side effects. Now, these medications work about half the time. And so it’s kind of shocking actually that expensive, invasive medications that have serious side effects

Solluna By Kimberly Snyder (33:56.974)
Right?

Kevin Tracey (34:06.362)
only work half the time. But that being said, it’s also important to point out that these same medications have made millions of people feel significantly better. So there’s value in them too. The point isn’t to criticize the available medications. The point is, no, the point is that the current patients, first of all, not everyone’s benefiting. And second of all, patients should be given the option of things. It should be that people who

Solluna By Kimberly Snyder (34:23.15)
Sure.

Solluna By Kimberly Snyder (34:33.165)
Great.

Kevin Tracey (34:36.042)
who want to try therapies that are FDA approved can do so with the support of, with all of our support and interest. And that’s what I see happening next. I see vagus nerve stimulation with these small devices implanted in the neck to be a game changer, frankly, in how we think about treating inflammation, first for rheumatoid arthritis, but eventually for many other conditions.

Solluna By Kimberly Snyder (35:02.156)
Yes, I was going to say you have a chapter about depression. Can you explain a little bit how potentially the vagus nerve might be implicated in depression? I know there’s different forms of depression.

Kevin Tracey (35:14.366)
There are different forms of depression and we don’t know what causes depression. We don’t know why one person’s depression might get better from a SSRI, a serotonin-based pill, and another patient with depression taking the same medication has no benefit. When you have a disease and you wanna make a therapy, it’s fundamentally important that the therapy target

the cause of the disease. If you don’t know the cause of the disease and we don’t know the cause of depression at the level of molecules, makes it very difficult, if not impossible, to make a specific therapy that will help everybody. So then what, yeah, but what do we know about depression? Well, we know that cytokines cause depression. So the last time you had the flu or COVID and you felt tired and anorectic,

Solluna By Kimberly Snyder (35:56.877)
Right.

Kevin Tracey (36:10.274)
and had no interest in your hobbies and maybe not even in your friends. This is a type of depression that is caused by the production of cytokines. The virus, whether it was the flu or the COVID, activated your immune system. Your immune system made these molecules like TNF, which are cytokines, and those cytokines travel to your brain and induce these changes in your brain that make you feel depressed. So we know…

There’s a link between inflammation and cytokines and depression. During the course of using vagus nerve stimulation to treat epilepsy over many decades, patients told their doctors that the vagus nerve stimulator made them happier. It made them feel better. And based on that, doctors and researchers did a series of clinical trials, putting vagus nerve stimulators in patients with depression.

And guess what? About half of them felt better. It was an effective therapy for about half of the cases. We don’t know why it was half. Maybe the patients that felt better after vagus nerve stimulation, maybe their depression was being caused by inflammation in their body and the vagus nerve stimulator turned that off. So these are the kinds of questions that are being asked. As of today, the FDA has approved

vagus nerve stimulation for treating treatment resistant depression in the United States and the European FDA as well. In the United States, it’s not used very often. There’s been some resistance to having surgery to treat a disease like depression, and there’s been resistance on behalf of the payers, the insurance companies and CMS to pay for this. Although I’m challenging my colleagues to continue to

Solluna By Kimberly Snyder (37:53.056)
Hmm.

Kevin Tracey (38:05.128)
study this question because it’s quite plausible that if we learned more about the relationship between inflammation and depression, we might be able to target this therapy to people who would most benefit.

Solluna By Kimberly Snyder (38:18.944)
Right. And again, just to have another option to alleviate suffering.

Kevin Tracey (38:23.742)
Well, you if you look at some of these clinical studies, yes, it only helped half of the patients, but some of the patients it helped went from being suicidal, unable to care for their families, to back at work. So I think we have to take a serious look at this and we have to say, we know some things, but we don’t know everything. It’s time to do more research and see if we can figure this out because people’s lives are at stake here. And if we get this right,

Solluna By Kimberly Snyder (38:33.123)
Yeah.

Kevin Tracey (38:52.53)
and learn enough, it might be possible to help more people than we are today.

Solluna By Kimberly Snyder (38:57.9)
Back to the very personal experiences you’ve had, Doctor, which I feel keeps driving you forward in that work with Janice and your mom. When you see how much impact there can be from one person’s suffering, potentially being avoided or alleviated, it’s like a fire that keeps burning under you.

Kevin Tracey (39:20.81)
When you meet a patient who tells you that they feel better because of something that my colleagues and I invented in my lab, that’s one of the happiest days that anyone could have in their professional life. And I’ve had the privilege and the good fortune and the good luck to meet now a handful of patients who’ve told me that. And it makes it all worthwhile. There’s nothing better than hoping for years that you’re

your work would alleviate suffering and then you meet these people and they cry and I cry and everybody, tears of joy and gratitude and it’s wonderful.

Solluna By Kimberly Snyder (40:05.356)
really beautiful. So switching gears just a little bit, there’s a section in your book where you talk about you are your reflexes. And as someone who has been studying Vedic texts, and being yoga for many, many years, doctor, it’s amazing how there is this repetition of talking about our nervous system, right? sort of, you know, between us and the world, there’s our nervous system, and it’s sensing and it’s has such an impact on our experience.

Can you talk about, again, the vagus nerve in relation to this overall experience of our reflexes and sensing and being in the world?

Kevin Tracey (40:46.14)
The vagus nerve is the main portal that carries information from your organs into your brainstem, into your brain. And so all day long, when you’re thinking about getting to work or finishing your project or picking up the kids at school or whatever it is you have to do that day, your organs are in the background telling your brain how much glucose is in your liver, how much insulin is in your pancreas.

how fast your heart is beating, how much urine your kidneys are making. All this information is being transmitted from the organs up into the brain all the time. Now, we tend to think that we sit here in our human brains and give instructions to everything. And that’s where it all starts, but that’s not where it starts. It starts with what you said. It starts with sensory input, with sensations, not the awareness of them.

but the actual signals made in your organs and in your skin and inside your lungs and inside your stomach, these signals are constantly traveling up into your brain through your vagus nerve and other sensory or afferent nerves. The arrival of these signals, not at the speed of light, but very, very quickly, the arrival of these incoming signals activates the outgoing signals

from the brain to the organs that are reflexive. Now we keep talking about the 200,000 fibers in your vagus nerve. These are carrying billions of signals, electrical signals that are activating billions of electrical signals going back down to your organs to make fine-tuned adjustments to keep your organs functioning in a healthy balance. After the fact…

The little you sitting on top of all this makes up stories about how your stomach feels or how your bladder feels or how your lungs feel. But it’s after the fact. Your awareness of these things are explanations of what’s going on in the background. It’s as if you’re sitting on top of your electrically active body making up stories about what it’s doing. yoga captures some of that.

Solluna By Kimberly Snyder (42:52.278)
Right.

Kevin Tracey (43:10.506)
You adopt a pose and then you decide to relax. And that relationship of input to storytelling is what I call the reflex basis of, as you said, the reflex basis of health. If your reflexes maintain a healthy balance of your organ function, reflexes mean you can’t control them, but if your reflexes keep your organs in a healthy balance, then you are healthy.

Solluna By Kimberly Snyder (43:15.246)
Mmm.

Solluna By Kimberly Snyder (43:40.578)
Hmm.

Kevin Tracey (43:40.71)
If those reflexes are damaged, or if the output of those reflexes is altered by say your state of mind or your level of stress and anxiety that disturbs the way those reflexes are supposed to be acting in harmony, well then your body will develop non-homeostasis or what we call unease or disease.

Solluna By Kimberly Snyder (44:05.994)
Yes. Yes. Well, again, I love how the book goes from explaining how the body works and then science and then this exciting new technology and then everyday solutions. I feel like it’s really fascinating for everyone to read the book, whether someone’s particularly interested in the science or the modalities or just wants to find out about the vagus nerve.

I could pick your reading for hours, doctor. Is there anything though that we didn’t cover or anything that you would want people to really get out of the book or to know about the book?

Kevin Tracey (44:45.726)
I think it’s really important that when you look at the self-help things, whether it’s cold plunges, getting enough sleep, eating a balanced diet, exercising regularly, having a secure and engaged social interactions, all of these things that grandma told us to do and your primary care physician is telling you to do, they are all associated with

slowing of heart rate, which is a function of the vagus nerve. So there’s an element of truth to the idea that these activities and your vagus nerve are in some kind of a harmonious relationship. What I tried to do in the book is explain the scientific truisms to each of these things without promising, promoting, or selling the idea.

Solluna By Kimberly Snyder (45:21.55)
Mm.

Kevin Tracey (45:44.072)
that we understood it all or that each and every one of these things has a way that it has to be done to optimize these either vagus nerve signals or health benefits. And so I hope the readers find that interesting because frankly, when I go on online and read the vagus nerve advice or the social media advice, I’m overwhelmed by it. So I tried to break it down and explain it in the useful way that would help people make their own

Solluna By Kimberly Snyder (45:51.785)
Right.

Kevin Tracey (46:13.138)
well-informed choices about what to do and how to do it.

Solluna By Kimberly Snyder (46:16.416)
Yes, and that definitely comes across, Doctor, again, encouraging people to use their own intuition and to not get overwhelmed into decision paralysis with everything out there, but it feels very grounded. And again, I love the personal stories and the humanness and the why, because it’s the fascinating healer’s journey too, right? Or the wounded hero, the struggles you went through very early on in your life, losing your mother.

and how you were able to really, you know, just focus your life on helping others. It’s such a beautiful story, Doctor.

Kevin Tracey (46:55.124)
Thank you. I really appreciate your kind words.

Solluna By Kimberly Snyder (46:58.848)
Well, tell us again, I know what the answer is going to be wherever books are sold, but tell us where we can get your book, The Preferred Place. Once again, everyone, it’s called The Great Nerve, The New Science of the Vagus Nerve and How to Harness Its Healing Reflexes. Where can we get it?

Kevin Tracey (47:18.536)
Wherever books are solved.

Solluna By Kimberly Snyder (47:21.6)
Love it. And where can we also find out more information about your work, doctor? Where’s your central hub?

Kevin Tracey (47:29.7)
I am the president and CEO at the Feinstein Institute at Northwell Health in New York. So those websites have some information, but primarily the book is heavily referenced. And for those who want to really dive into the science and the clinical trials and the work that’s gone on for the last 30 years in this space, all of those references and citations are found in the end notes.

Solluna By Kimberly Snyder (47:53.172)
There’s literally hundreds of them. But again, I want to emphasize that the book is also very readable. And so the science is there and you can reference it, but it doesn’t. It’s not like a textbook. It’s actually like a story and it’s entertaining and it’s accessible and it is fascinating. So I recommend everybody pick up a copy. We will link directly to the book in our show notes at mysaloon.com as well as more information on Dr. Tracy.

and other podcasts I think you would enjoy. So thank you so much, Doctor, for being here with us today and sharing a piece of your wisdom with us.

Kevin Tracey (48:26.868)
Thank you for having me on, I really appreciate it.

Solluna By Kimberly Snyder (48:29.358)
Thank you everyone for tuning in. We’ll be back here next week for our next interview. Once again, head to the show notes, mysaloonah.com. I’ll see you on social at underscore Kimberly Snyder. Until then, wishing you all the best and so much love.

Solluna By Kimberly Snyder (48:48.642)
Yay!