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

by Kevin J. Tracey MD

New science reveals the groundbreaking potential of the vagus nerve to regulate your body’s vital systems and heal a wide variety of medical conditions without drugs

The vagus nerve is fundamental to our health and vitality, coordinating critical functions  from the precise heartbeat we need to exercise or rest to the balance of appetite and digestion. Made up of 200,000 fibers, the vagus nerve sends thousands of electrical signals every second between your brain and your most important organs. Yet despite its essential role in life, important vagus nerve functions have eluded centuries of scientific investigation. Now neurosurgeon and researcher Kevin Tracey has discovered the previously unknown power of the vagus nerve to reverse inflammation, balance the immune system, treat chronic illness, and keep our organs humming together in harmony.

    In The Great Nerve,  Dr. Tracey shows us how stimulating the vagus nerve with a tiny electrical implant has the potential to reverse life-altering diseases like rheumatoid arthritis, inflammatory bowel disease, lupus, MS, diabetes, obesity, stroke, depression, Alzheimer’s and Parkinson’s. If this sounds too good to believe, Dr. Tracey shares stories of patients who have gone from being nearly bedridden to running and dancing, along with the science that makes possible these recoveries. He also explains the evidence for lifestyle strategies like ice baths, meditation, exercise, and breathwork that can maintain and improve vagus nerve function. 

    By opening the door to the new field of neuroimmunology, The Great Nerve not only revolutionizes how we understand and treat disease, it gives us unprecedented hope for our health. This is the story of your body’s ability to heal itself.

Genres: Health, Science, Nonfiction, Neuroscience, Self Help, Medicine

320 pages, Kindle Edition

First published January 1, 2025

Reviews

[Andrea Rdz · Rating 2 out of 5]

Promising ideas, but the science isn’t there yet.

The research history around the vagus nerve is fascinating, and I appreciated learning about the studies that led to monoclonal antibody anti-TNF therapies. But the book ultimately feels like a sales pitch.

As someone with an autoimmune disease, I was very interested in new approaches, but the “practical applications” for readers are speculative, and nearly all the success stories involve implants. While the science behind bioelectronic medicine is promising, the strongest evidence so far is limited to epilepsy and treatment-resistant depression. For autoimmune and inflammatory diseases, it’s still very early making this more advocacy for an implant than a useful guide.

[Ellie May · Rating 2 out of 5]

Part of the disappointment is my fault. I wanted to learn more about the vagus nerve and thought this would be a good start, BUT the title does say “the new science and how to harness its healing” and not “all about the vagus nerve.”

Alas, also maybe I’m too dumb for it. I read the whole thing and don’t feel like I understand how the vagus nerve works. This contained a ton of patient examples of them using new devices that stimulate the vagus nerve successfully, and experiments that went well for the vagus nerve - but WHYs and HOWs were buried on all that which made it messy.

Not very cohesive, he’s definitely a smart neurosurgeon but could have used a writer to assist him making this flow/read better for average joes.

[Mary · Rating 5 out of 5]

Are you currently struggling with an illness? You may wish to consider reading The Great Nerve. Here is a wealth of information to understand the groundbreaking technology of vagus nerve stimulation. I suffer from rheumatoid arthritis, and now feel great hope that this treatment will improve my life once it receives FDA approval. It offers hope also for epilepsy, Crohn’s disease, diabetes, cardiovascular disease as well as depression and anxiety. Explained in easy to grasp language, Dr. Tracy will guide you through his years of research and other studies to understand the miraculous workings of the vagus nerve. This is not just a scientific look, but contains the real life stories of deeply ill people who have benefited from these targeted treatments. We have entered a new age. No longer are we strictly limited to drug dependent therapies, but now we can access the benefits of device stimulation to improve our health and wellbeing.

[Sharon · Rating 4 out of 5]

Absolutely fascinating. Truly a new frontier in medicine. I can see why the pharmaceutical companies would be a bit freaked out that their billion dollar biologics will be at risk. I also like the focus on what you can do at home like meditation, deep breathing, and cold therapy. There also seems to be a new wave of devices being tested that you can use at home. I could’ve done without the details of vivisection and animal torture, especially since the FDA no longer requires animal testing for approval.

[Elizabeth CHALLIS · Rating 3 out of 5]

I skimmed this book. It gave me information about how the vagus nerve works. That was fascinating. However, I tried not to think about how discoveries about the workings of the nerve were made in the past: it had to be gruesome.

The author has a cute story about how his brother fooled him into jumping in the very cold lake water; it was funny.

I think he is a fan of cold showers for your health. I’d like to do that, but…. Yowza! Too cold.

This author thinks that, in the near future, medical therapies involving the vagus nerve will help with some heretofore incurable diseases, like Parkinson’s. I hope he is right.

[Jodene · Rating 3 out of 5]

Our bodies and minds are amazing. This is a book to help with self awareness and tools to recognize and control reactions that may have a negative effect on health.

[Kiley · Rating 3 out of 5]

This book fell so short of what I hoped it would be. I wanted more definitive answers and information about what vagal nerve stimulation can do for health, but overall it was pretty darn speculative and in need of larger randomized studies. (Seemed like it is only proven for epilepsy and extremely-treatment-resistant-depression are definitive at the moment). Also there were moments where the author just came across as conceited rather than excitedly sharing his work. Hopefully this field does continue to be studied and someone else can provide us with a more definitive book about the benefits of vagal nerve stimulation and if it can be achieved in other ways besides surgical implants.

Notes:

Vagal tone = vagus nerve activity = neurological activity of parasympathetic nervous system (48:25)

Vagal tone improved by physical exercise, meditation, breath work, & cold exposure (48:34)

Lower pulse = progress towards happy & healthy bc it can signify you’re living in ways that chronically stimulate your vagus nerve (1:13:16)

HRV = heart rate variability (time between heart beats), higher HRV indicates stronger Vagal tone (1:16)

The first five minutes of chapter three contain major trigger warnings (scalding burn wounds to a child ultimately resulting in death). Lab animal testing may also be upsetting to some readers (esp instances in this chapter where a lab rat and baboon die as a result of testing).

A lot of this chapter was very dense (talk of TNF and anti-inflammation, three experiments and “oh shit aka eureka” discoveries) and largely had my eyes glazing over

“Recall 80% of your vagus nerve fibers are sensory, capable of relaying prodigious quantities of information about the minute to minute status of your immune system” (2:20:30).

Transcutaneous auricular vagal nerve stimulation taVNS

Doctor friend applied TENS, after minor heart attack, to cymba concha & stimulated left ear for five minutes twice a day with a pulse width of 200 microseconds, and a frequency of 20 hertz, varying the pulse amplitude between 2-4 milliamperes as tolerated. Improvement within 2 weeks (4:59).

Applying a TENS unit to the ear is a method of TAVNS. Depending on the location of the electrodes and the specific neuroanatomy of the subject using a tens device on your ear may deliver electrical pulses to the auricular branch of your vagus nerve (5:09).

Meditation won’t hurt, may help but not yet proven. Breath work appears to be similar.

“As in all scientific fields, vagus nerve research is work in progress … and it means that this audiobook is a teaser of possibilities” (7:05, edited).

“By admitting what we don’t know yet I aim to give credibility to what we do know already, share this knowledge with people who can use it, and encourage patients to advocate for themselves” (7:36).

[Gabriel · Rating 3 out of 5]

Author sounds like a very accomplished dr. He provides some interesting potential for implanted nerve simulator, which unfortunately would be out of reach for most due to cost. Not much was provided for other new potential treatments and nothing new for self treatment. If you are looking to this book for a fix it's not it, unless you have $10s of thousands to spend on an implant

[Isaac · Rating 3 out of 5]

I first took an interest in the vagus nerve after finding myself clutching a trash can, wracked with nausea at my annual eye exam. The doctor had been doing normal screenings when I was suddenly gripped by a need to throw up. The doctor, perplexed, backed up, handed me the trash can, and waited. As we tried to figure out what was going on, he mentioned the vasovagal reflex and how, in rare cases, the nervous system reacts to a specific trigger, blood pressure tanks, together with nausea or lightheadedness, and fainting often follows.

That something so seemingly unconnected to my stomach as an eye exam could make me nearly pass out made me realize how fascinatingly intertwined are the body's systems.

It was with great curiosity that I read Dr. Tracey's popular-level memoir of a career's work on the vagus nerve with its 100,000 connections throughout the body. It lacks the splash and buzz of sensationalized pseudoscience and follows the dull, painfully slow incremental process that characterizes good science. Tracey avoids making any remarkable claims but merely provides the frustratingly incomplete extent of current research into the vagus nerve.

At this point, we can be confident that conditions such as epilepsy and inflammatory diseases such rheumatoid arthritis can be treated in many cases by vagus nerve stimulation. Beyond that lie many tantalizing opportunities (e.g., GLP-1 agonist replacements, non-pharmaceutical depression treatment) that show promise but have not been adequately researched or FDA approved. I was particularly intrigued by the connection between cold showers/plunges, the mammalian dive reflex that slows heartrate, and the reduction of inflammation. Unfortunately, many of the inflammatory markers in the blood are very short-lived and are difficult to measure clinically. Plus, it's impossible to conduct a double-blind study of cold plunges!

I was reminded of the difficulty with which scientific progress is made practical and gained more respect for those doing work to make it happen. I absorbed a bit about the vagus nerve, but there is so much more to learn.

[Kathleen · Rating 3 out of 5]

I was hoping to learn more about how the vagus nerve works and also how to stimulate it naturally. Tracey did say he was going to cover the latter and I guess he did but lazy me, I was hoping for a concise, bulleted, how-to? There was lots of anecdotes but I wanted more study data.

[Christa · Rating 2 out of 5]

I really didn’t finish this book. It had more to do with a machine treatment and not just natural treatment

[Elyse · Rating 4 out of 5]

A quick, engaging, inspirational story of the frontiers of scientific discovery.

Trigger warning: vivid descriptions of animal research.

Four stars due to the importance of the findings. Inexpensive and minimally invasive vagus nerve stimulation could one day replace costly biologics and provide ways of healing from within. Imagine curing Parkinson's or MS or Depression without drugs! What would your life be like if you could get the appetite suppressing benefits of a GLP-1 drug by targeting sound waves at your spleen? Or better yet, breathing at a certain frequency? And if you know anyone with Rheumatoid Arthritis, give them this book. A dramatic cure is now at hand (pending approval from your particular doctor and insurance company).

That said, much of the book is a retread of well-known web based tropes to "hack your vagus nerve". This does nothing to minimize the findings, but it is hard not take the author's words as a wink-wink encouragement to go rogue and start the n=1 experiments. After all, there is no cost to meditation, breathing or cold showers, and minimal cost to purchasing an external vagus nerve stimulator.

The author does a decent job separating what is known through scientific research (and how the quality of research effects the stability of finding), from what is known through Traditional Chinese Medicine, or Ancient Meditation practices versus web based influencer fluff. Tracey encourages the reader to review the literature, or at least the indexed reference section at the back of the book, before drawing too many conclusions.

One caveat: The author refers to the function of the nervous system as being based on reflex arcs, which to my (admittedly limited) understanding is oversimplified and outdated - meaning, behavior is based on both reflex and predictions. I'm not sure how important that is to mention. Perhaps, a complicated description of the nervous system would distract from the main thrust.

Finally, I would have loved a section that discussed what is known scientifically about the vagus nerve and how that might relate to the popular, albeit scientifically dubious, Polyvagal theory that has overtaken somatic psychology. Again, perhaps this would be out of scope. That said, it's hard not to draw my own conclusions that Stephen Porges' Polyvagal theory is likely a gross oversimplification of "The Great Nerve".

[Eyelandgirl · Rating 4 out of 5]

This is a very informative book about the Vagus nerve. It is split into thirds; the first section gives you some background information and the third section gives you some everyday tools to try and stimulate your own vagus nerve based on the science that we know. The middle section was a bit bogged down in the science, and can be skipped or read if you want.

The science is not where you might hope it would be, but it certainly is interesting... especially the crossover between traditional Eastern treatments such as acupuncture and the pathways and functions of the vagus nerve. Energy work (that has often been treated as a bit airy fairy) seems to be lodged firmly in the real world of the vagus nerve.

The author has clearly done some great things in science and innovation, but it did come across a little self-serving comparing himself to the greats of medicine (Pasteur, Salk)... that really is for history to decide!

Like many similar books, there are lots of single case studies that sound remarkable. but there was a complete absence of any negative outcomes or results.... which seems too good to be true. And although stimulation of the vagus nerve stimulation has been used extensively for epilepsy and a bit in depression, it seems underutilized for the other things influenced by inflammation.
Perhaps it is so novel that science has not caught up, but it is surprising that something so full of potential has not been further investigated for all the different inflammatory conditions from which humans suffer. (he does sight on going clinical studies at the end of the book).

I was also surprised that the use of TENS machines to stimulate the aural Vagus pathway wasn't more thoroughly tested and explained. (he mentions the millions of results on the internet if you look it up, but doesn't help you wade through what type of device and electrodes to look for if you want to try it yourself). It seems that would be the most accessible route for the general public to try and stimulate their own vagus nerve.

The book certainly had me intrigued and I look forward to learning more as the science develops.

[Cheryl · Rating 4 out of 5]

This is a very informative book about how the vagus nerve affects so many of our bodily functions. It explains how electrical implants have the potential to treat illnesses such as epilepsy, rheumatoid arthritis, inflammatory bowel disease, lupus, MS, diabetes, obesity, stroke, depression, Alzheimer’s disease and Parkinson’s disease. It might sound much too good to be true, but at one time, I’m sure a heart pacemaker sounded too good to be true as well.

I enjoyed the scientific explanation of TNF (tumor necrosis factor) which is a molecule made by the immune system that can cause the same type of tissue damage as some bacterial toxins. Currently monoclonal anti-TNF antibodies are widely used anti-inflammatory drugs to treat diseases like rheumatoid arthritis and inflammatory bowel disease.

As a result of various experiments which are described in the book, scientists have discovered that signals from the vagus nerve can stop the production of TNF. The author writes, “If the vagus nerve regulates the immune system through an anti-inflammatory, healing reflex, then it should be possible to regulate inflammation with devices that stimulate the vagus nerve in patients. And I was confident that this could happen because, as a neurosurgeon, I knew that vagus nerve stimulation was even then being routinely and safely performed to treat patients with epilepsy.”

In the appendix, there are charts indicating various diseases that are being treated right now with vagus nerve stimulation using implanted devices, including the dates of their FDA approval. The appendix also includes charts listing many diseases whose clinical trials are underway to determine the effectiveness of vagus nerve electrical stimulation for their treatment.

In time, just as heart pacemakers have become commonplace, vagus nerve stimulation using implanted devices to treat many diseases may become commonplace as well.

Interesting read.

[Rich · Rating 4 out of 5]

Personal Notes

The Vagus Nerve or Great Nerve is actually two bundles of nerves, one on each side of the body. The bunldes have approx 100K nerves in them and connect the brain to the body. Each nerve contains many sensory and motor fibers responsible for transmitting information related to taste, touch, heart rate, and digestion, among other functions.

Originally it was thought that there was no such thing as too much inflammation, that the body would produce just the right amount required. But studies have shown that in some cases inflammation can run away and start attacking the body.

Chronic Sympathetic activation increases inflammation, chronic stress increases inflammation. The catecholamines released bind to receptors in the immune systems blood cells stimulating these blood cells to produce more cytokines that increase inflammation. They sensitize the white blood cells to inflammation, causing them to respond aggressively next time there is a stimulus. This state means even a minor injury or infection leads to an overreaction. This results in too many TNF molecules.

Inflammation is thought to be present in all illness, and may even be the root cause of illness.

Studies show that stimulating the vagus nerve can reduce inflammation; in a similar manner to anti TNF molecules that reduce inflammation.

The Vagus nerve can be stimulated using an electrical device like a pacemaker which applies a small current to the nerve directly. This has been shown to benefit many, if not all patients, with Epilepsy, Rheumatoid Arthritis, Crohns.

Other non surgical methods include:
* breathing (3/7 breath)
* cold therapy
* meditation
* TENS machine on a specific spot on the ear. (this has been shown to reduce inflammation by 50-75%, but it's not clear if this is due to vagus nerve stimulation

[Joshua Bradley · Rating 5 out of 5]

It took me months to finish The Great Nerve because every page turn told me something about the last 14 years of my life struggling from the rapid onset of Crohn's disease. Unfortunately, I didn't know about Tracey's work, or about vagus nerve stimulation. I certainly found my way through all kinds of things that were considered voodoo in the 2010s, like fasting for health benefits, therapeutic ketogenic diet, and mixing my own mineral ketones to boost the inflammation and energy benefits, hooking myself up to an electrical pulse machine attached to the vagus nerve would have been easy to say yes to.

Now, as the book points out, devices are being approved and researched for debilitating diseases like MS and inflammatory autoimmune like RA and Crohn's disease. What I didn't realize was Tracey's work was also what made medications like Remicade, a TFNa blocker, possible. A medication that saved my life due to its powerful abilities to stop the fistula creation that was tearing me apart.

The last part of the book explores ways to stimulate the vagus nerve that don't involve a medical device. One of them, a TENS device I picked up from Amazon for $35, has been a lifesaver after surgeries, when pain medication failed. I'm deep into my surgical journey and off of the medication, in deep remission, but I've used these strategies to maintain resilience and help others. This work on the vagus is extraordinary because it could take millions out of the pharmaceutical cycle for everything from depression to autoimmunity. Reading about how electrical pulses can just turn off inflammation made me tear up with sadness for my past and hope for all those suffering now.

[Peiji · Rating 4 out of 5]

I am currently studying Acupuncture and the vagus nerve is a huge part of the practice. As someone with a holistic nutrition background, it is also commonly discussed. There is constantly new research and I was excited to read more about this great nerve from Dr. Kevin J. Tracey.

I was hoping there would be more information about the nerve and its relationship to the different organ systems in the body, but this was still a good read. This book is great for someone seeking for alternative ways to reduce or treat their inflammation of various kinds.

It is a great way to open up your mind and learn more about health sciences. Although this book is not the answer to everything, I like how it is constantly being researched and this book gives you a peak into what could happen in the near future.

[Ylan Roy · Rating 4 out of 5]

Read this book as part of my long Covid reading stack. As many of us are diagnosed with autonomic dysfunction. Literally, our nervous system is now broken.- it could be due to viral persistence in this particular nerve- or simply the vagus nerve responding to the threat- stuck in fight or flight. This book described the science behind implanted vagus nerve stimulation. It also touched upon Vagal stimulators that are placed on the ear. Breath work, cold immersion, and other related topics were discussed briefly. Worth a read to understand the complexity of this great nerve. Trust me you’ll miss it if it starts misfiring. I was rowing daily when I got my only mild Covid infection felt like a bad flu. Three years later, I use a power wheelchair. Mask up and stay safe friends.

[Dianna · Rating 4 out of 5]

This book was super interesting and got me out of a reading slump. The author is a doctor and biomedical researcher who has been studying the vagus nerve and inventing devices to stimulate it. There are some miraculous stories of healing in this book, but to back them up, Dr. Tracey has also published many research studies.

The only downside of this book is that it left me wishing the research was 50 years farther along than it is. This is definitely something to look forward to!

[Carlos Nunes · Rating 4 out of 5]

The Great Nerve is an accessible and insightful book that explains how the vagus nerve influences health, from inflammation and immunity to mood and chronic illness. Kevin Tracey shares science and patient stories in a clear, grounded way, offering knowledge and cautious optimism about future treatments.

[John Stockton · Rating 5 out of 5]

A stunning and powerful example of what can occur when curious and determined scientists and researchers investigate and research up to date discoveries to assist patients who have been suffering for many years.
I see some readers feel Kevin Tracey is conceited, I can only assume they have only lightly skimmed this amazing book, and have ignored the break through discoveries and applications that have brought relief to so very many! An astounding book!

[David · Rating 4 out of 5]

This book provides a fascinating look at our vegus nerve and sheds light on the kind of possibilities that might be available to us for a variety of issues. It sounds strange, but I've seen a significant other benefit from tapping into treatments related to vegus nerve stimulation. I'd love to see research continue in this space!

[Yana Petrova · Rating 3 out of 5]

If you’re already into health podcasts, you’ll probably find little that’s new here. Overall, it’s a good starting point for those interested in the mind–body relationship and ways to improve their life and health.

[Amy Gingrich · Rating 4 out of 5]

Fascinating explanation of the emerging role of bioelectronic devices in treating medical conditions. The author goes into great detail about his work with Vagus Nerve Stimulators (VNS) devices - what they are currently approved to treat and what they may be approved and used for in the future.

[Jace Stansbury · Rating 4 out of 5]

Incredibly informative. An exciting advancement in the treatment of inflammatory disease.

[Caroline Hanna · Rating 4 out of 5]

super interesting!!! highly recommend

[Sandi · Rating 5 out of 5]

Absolutely mind expanding.

[Emilia]

[i love the topic but this book could’ve been a 10-minute ted talk]

[Yeezy · Rating 3 out of 5]

I've always liked the name "vagus nerve." This is a popular science book about the vagus nerve, which includes some medical advice.

[James · Rating 4 out of 5]

Dr. Tracey has written such a compelling, informative, and potentially transformative book.