Season 3, Episode 8: Stimulating the Vagus Nerve Function with Dr. Navaz Habib

Evelyne: Thank you. Dr. Navaz Habib is the bestselling author of Activate Your Vagus Nerve and the newly released Upgrade Your Vagus Nerve. He’s also the host of The Health Upgrade Podcast. After graduating as class valedictorian from Canadian Memorial Chiropractic College in 2010, he went on to practice traditional chiropractic for years until he utilized the power of functional medicine to transform his own health. Dr. Habib is the founder of Health Upgraded, an online functional health consulting clinic supporting optimal health by elevating the awareness and function of the vagus nerve. So let’s start with an overview first. What is the vagus nerve and what do practitioners need to know about it?

Dr. Navaz Habib: That’s a great question and most practitioners are aware of the vagus nerve. I think that’s a pretty simple question to answer. It’s the 10th cranial nerve. It is the parasympathetic control system for the body, but I think we’ve underrepresented how important the vagus nerve is to health, and I think this is where practitioners can really gain some definite benefit to how they approach their patient’s health by utilizing strategies that have proven to improve vagus nerve function in the first place. And from a practitioner standpoint, we often just learned about the vagus nerve one time in class. Doesn’t matter if you were in medical school or naturopathy or chiro or whatever form of, like holistic nutrition, whatever it was that you practiced or whatever you were taught from, it was a very brief overview of this particular nerve.

What’s unique about it is that it does not follow any of the same patterns as any of the other nerves in the body. It is the only cranial nerve to leave the cranial cavity, which is the head area. It’s the only cranial nerve that travels with the carotid artery and the jugular vein in the neck. And it’s the only nerve that connects to essentially every organ that we have, from the heart and the lungs in the thorax to the stomach, the abdomen, or any abdominal viscera, to the pancreas, to the liver, gallbladder, to the intestines, you name it. There’s a connection directly to those organs from the vagus nerve.

I think what’s happened broadly in the educational sense is we haven’t been given this importance to what the vagus nerve really truly does within the body, and it is the inflammatory control system within the body. And you’re actually the first talk that I’m doing since a new article just came out in Nature talking about this particular body-brain connection that regulates inflammation and they literally break down the neuron types that are involved in inflammatory control all being located within the vagus nerve and vagus nerve control centers.

Evelyne: I definitely want to get into that and talk more about inflammation. I’m also curious, Navaz, you personally in your bio had said you had your own transformation. And I’m curious, how did you get into specializing in the vagus nerve? Was it because of your own health journey or was that separate?

Dr. Navaz Habib: It’s a bit of both. My story from my health journey was that when I was in chiropractic college, I weighed 250 pounds, high blood pressure, borderline diabetes, sleep apnea in my twenties. Pretty significant challenges for anybody to suffer from, but I was doing it in my twenties. And I had not learned how to take care of myself at all. I had no real understanding of the practical nature of what I was learning in chiropractic college and how to apply it to my real life. And it was a chance encounter with a fellow functional medicine practitioner and mentor and wonderful friend of mine, Sachin Patel, that really introduced me to this concept of functional medicine, the concept of true holistic health and what it really meant to show up and be present and be healthy every single day. And so it was that journey that brought me into the functional medicine world.

But that said, I’ve always been uniquely interested in the vagus nerve. It stuck out as just being different or special or unique in my entire journey. So when I was in chiropractic college, I remember first day cadaver anatomy lab I was there early. I was the keener for the anatomy side of things and very much so on the neuro side. So the brain anatomy really was my calling. But how the brain connects to the body and how it controls and perceives what’s happening in those areas was always of interest to me. And it turns out that the vagus nerve plays a very important role in that particular piece.

And so it was through my journey while I was learning about inflammation, while I was learning about gut-brain axis, while I was learning about all of the connections that are built there, it turned into the vagus nerve is this uniting force between the body, the brain, and how the brain then signals to the body again. And that’s really what drew my interest to the vagus nerve as being this really important one for us to not only look into but really work to optimize.

Evelyne: Great. Thank you so much and thank you for sharing that story. I’m curious about the body-brain connection a little bit more. So the vagus nerve has both afferent and efferent fibers. Can you explain that more and how many or what percentage?

Dr. Navaz Habib: This is one of the really important things to understand. We often think vagus nerve is sending parasympathetic signals brain to body, and that’s just essentially it. But 80%, that’s four fifths of the fibers on the vagus nerve are afferent, meaning they’re coming from the organs, the signals are coming from the organs up to the brain. What that means is all of the status updates of what’s happening within the microbiome and the gut, what’s happening within the liver, what’s happening in the kidneys, what’s happening in the lungs and the heart, all need to make their way up to the brain and the way that they do that is through these vagal afferent fibers. And so the only reason that our brain knows what’s happening in the heart with our heartbeat or in the blood vessels with our aortic arch baroreceptors and carotid baroreceptors that come through the vagus nerve, and what’s happening in the lungs and all of these areas in terms of an inflammatory signature, inflammatory cytokine activity that’s present there, is simply because the vagus nerve is able to send those signals up.

And so you can imagine if that signal or if that pathway is hindered in any way, is not functional or becomes dysfunctional in any way, those signals are going to be less likely to make their way up or less effective in making their way up to the brain. And so the brain doesn’t have good information as to then what to do about it or what signals to send through all of the other nerves or any nerves to those organs to say, “Okay, cool, let’s chill out the inflammation” or, “Let’s go into more of a sympathetic state.” We don’t know. And so when we don’t know, we tend to overreact and that seems to be the pattern that’s occurring within the body. So 80% of the information on the vagus nerve is afferent coming up.

15%, 1-5%, of the information on vagus nerve is from the brainstem to those same organs. And so that’s the effector function, that’s the we’re going to send a signal to the cells that are present in those particular organs so we can get into the cell type that I’m looking at specifically, but that’s the signal that we know is parasympathetic. But that only makes up the 15% of information on the vagus nerve. For the math people, there’s about 5% missing there. So that means about 4% is actually motor and that goes to the laryngeal and pharyngeal muscles through the branches, the pharyngeal and laryngeal branches of the vagus nerve. So that goes to keep airway patent, good motor control of the airway, of the vocal cords through the laryngeal muscles. So that allows for us to have pitch and tone in our voice. So the reason I can go really, really low or really, really high with my voice is because I have that constrictor control through the laryngeal branches.

And that’s the 99%, that one last percent that’s available is actually from the skin of the auricle of the ear in the certain area inside the concha of the ear. So it’s the skin overlying, not the outside of the auricle, but on the inside of the auricle of the ear that is a branch of the vagus nerve called auricular nerve or the auricular branch of vagus.

Evelyne: Very interesting. Thank you for sharing that. And it’s just fascinating how much of that communication goes up and not the other way around. You mentioned the sympathetic nervous system. How does the vagus nerve influence the balance between the sympathetic and parasympathetic?

Dr. Navaz Habib: The simplest analogy that I’ve been able to come up with on this is simply the analogy of the accelerator and brakes in a car. And so when we have a car, we have these two pedals. We used to have a lot more with three pedals, but we’ll just go with the two because it simplifies it. So we’ve got the accelerator and we’ve got the brakes. And the accelerator is this get up and go driver. And that’s the sympathetic nervous system in our body. When we need to engage, when we need to move, we push the accelerator. And that’s great because without an accelerator, the car is sitting there as a piece of junk in the garage. It’s not doing anything, not going anywhere. It’s useless. In order to go, we need to be able to push that accelerator effectively, and that’s the job of the sympathetic nervous system in our bodies.

As we are going, there’s going to be incidents or times when we need to slow down where we need to back off, stop sign, red light, pedestrians crossing, kids running, whatever it is. We need to learn to push the brakes during those moments. And so we push the brakes to slow the car down and to ensure that there’s safety in what we’re doing, and we’re not constantly just pushing on the accelerator in a go fashion. So having this counterbalance of sympathetic accelerator and parasympathetic brakes is the real analogy that I find works the best because it’s a very dynamic process. It’s not like it’s a seesaw, that one is up and one is down. Both can be pushed at the same time, but it’s not effective to do so. And a lot of people are pushing both at the same time, even unknowingly.

So this analogy is really easy for me to explain to my patients, to my clients, and I find that a lot of practitioners love this because they can then share what they’re talking about. It’s saying your brakes are a little burnt out. They’re not working as well as we want them to. The vagus nerve, for whatever reason, it’s dysfunctional, and it’s just because you’ve got a ton of bricks sitting on your accelerator pushing you in this sympathetic go direction, which we don’t want to be in all the time. So this is an important way to analogize and to share that with clients.

Evelyne: Yeah, great analogy. Thank you. So what are some of the common conditions and symptoms that can be linked to vagus nerve dysfunction and then weaving in there another question which you may answer at some point because I have so many questions for you, but is the vagus nerve the problem or is it a symptom? And maybe I’m thinking about this too simplistically or… I don’t know, but this is something I’ve been pondering.

Dr. Navaz Habib: I don’t think you have it wrong by any means. I think there’s a curiosity into understanding that if this is dysfunctional, it must be the problem. In reality, for me, the vagus nerve is a thing that needs to be working effectively. And when it’s not working effectively, the problems occur because the control piece is gone. I love this analogy, or I love this concept. I’m a big fan of the Matrix, and there was a line in the Matrix where Neo was speaking to one of the members of the council in the city of Zion. It was in the second movie, I believe. And he talked about how the city of Zion functions with the use of these machines, and there’s machines that are out there trying to kill or keep humans as their batteries. And then there’s the machines that are being used by the city of Zion to keep the city of Zion running.

And the answer that, or the question that Neo asked was, “What’s the difference between these machines out here that are keeping us alive and the ones out there that are trying to kill us or to use us?” And the answer was control. We have control over these second set of machines. We can shut them off if we ever need to. And this is the concept of what the vagus nerve does, is it senses what’s going on and determines if it needs a shut-off or senses what controlling signal needs to be sent. Does it need to be pushed into a sympathetic state? And so if need be, then the vagus nerve can back off on its signaling. But if it needs to be pushed into a parasympathetic rest, digest, and recover and repair state, then the vagus nerve can be turned on.

So the vagus nerve is not the problem, but I would rather say that the vagus nerve is being dysfunctional is the problem and the most common problem that I see, because what we’re then having is inflammatory control issues. We are not able to truly control the inflammatory process because the crux or the linchpin to that inflammatory control signal is the function of the vagus nerve. I hope that makes sense there.

Evelyne: Yeah. So what are some of the common conditions or symptoms that you see related to that?

Dr. Navaz Habib: Conditions-wise, anything inflammatory, anything chronic is really telling me that there’s something inflammatory that’s not being controlled. So I’m looking at autoimmune conditions, often I’m looking at gut dysfunction being a huge issue here. Obviously any SIBO is a huge issue, like any small intestinal bacterial overgrowth. Often will find that practitioners are providing herbal remedies, which, as they should be, these herbal remedies are great, these therapeutic tools to help kill off any bacteria that should not be present. But the missing piece often is motility. And that motility piece is driven by that vagus nerve signal into the gut to say, “Yeah, turn on your peristaltic motion. Let’s get that food or that bolus moving further down into the large intestine where it should be located.” Or ileocecal valve tone. When that valve is dysfunctional, things can flow backwards from the large intestine, the ascending colon, back into the small intestine where it should not be. It should be unidirectional flow with a good strong valve to stop the backflow of whatever’s happening. And so when vagus nerve is dysfunctional, things like SIBO really pop up.

Other conditions that are directly associated with vagus nerve dysfunction. POTS, for example, postural orthostatic tachycardia syndrome, just dysautonomia as it’s been referred to, which literally means dysfunctional autonomic control, meaning that you have involuntary control over the automatic processes of your body. And so we don’t have great overall autonomic function, and that’s that balance between sympathetic and parasympathetic. But the most common ones that I’m working with in my practice, no question, have some gut issue included within them and have then resulted in some other inflammatory condition like a fibromyalgia, SIBO, ME-CFS, things like that. So we’re looking at that whole chronic inflammatory pathway as being the more common challenges that vagus nerve is involved with at its depth.

Evelyne: And do you find that those patients who have the gut issues also have mental/emotional issues, like more so than stress and mood issues, but more complicated conditions?

Dr. Navaz Habib: Yeah, as we know as practitioners now, the percentages of serotonin, dopamine production, norepinephrine production in the gut are heavily associated with this. And so one of the more common things that pops up is patients feeling very anxious or actually dealing with anxiety, depression, serious mental health issues that have popped up not only because of the health conditions but associated with them. And so what I’m seeing very often are, with regards to mental health struggles, some sort of dysfunctional gut motility piece or gut bacterial piece. And so the use of herbal strategies to help manage those in addition to the vagus nerve strategies tend to work really well. But the correlation between vagus nerve dysfunction, low HRV findings, low findings on vagal tone overall are heavily heavily linked to every single mental health condition you can ask for. Anything from depression, anxiety to PTSD and other just major traumatic stress type incidents.

Evelyne: Thank you. It just seems like this is the missing piece and we don’t always implement it because we’re not always thinking about it, so super interesting. So what causes the vagus nerve to become dysfunctional in the first place?

Dr. Navaz Habib: It’s a great question. And so the answer is what causes the brakes in a car to break down? We have to start asking the question of why would the brakes wear out in a car in the first place? Either you’re pushing them too hard because you’re driving too fast and you need to put on the brakes real hard, or there’s an actual breakdown in the system occurring. So the more common ones, there’s four different types of challenges that push us so hard on the accelerator side that I’ve broken it down to that will have a real effect on the ability for the parasympathetic nervous system and for the vagus nerve to do its job of controlling that stress. And so these are four areas of distress that I think we need to look at as practitioners to ensure that we’re supporting our patients.

Number one, daily/emotional stress. These are the day-to-day challenges, financial challenges, dealing with kids, relationships, what’s going on a day-to-day basis. And these stressors tend to chip away a little bit. They push the accelerator just a little bit more. And on occasion it can be more than we want them to be, but they chip away and they have a compounding or growing effect as they go if they’re not dealt with regularly with some sort of stress management strategy. The next area is physical stress. Physical stressors are things that we tend not to look at as practitioners and something that I think we have as low-hanging fruit. Has the patient ever had a car accident, a concussion, some sort of slip and fall injury? Were they ever the physical victim of a crime or something that caused a physical dysfunction in them? Was there some sort of traumatic incident that had a physical nature to it that needed to be addressed?

Second one, this one we’re pretty good at, is are they moving enough? Are they too sedentary? Are they not moving? Are they not exercising? Are they walking? Are they sitting all day going from car to office to car and not having those movement patterns optimized? Are they moving too much potentially as well? Often this is more on the athlete side of things. Are they overdoing it? Are they pushing themselves to a point where recovery is not being optimized? So we need to get into that balancing point with regards to the amount of physical movement.

On the third category here is biochemical stress. Biochemical stress can be too much of a bad thing or too little of a good thing. So too much of the bad thing, we’re looking at things like lipopolysaccharide, how leaky is their gut? Do they have mold in their environment? Do they have potential Lyme disease? Do they have potential biochemical dysfunction due to external factors that have penetrated and entered the body in some fashion? And then on the lack of good things, what’s their nutrition like? Are they getting enough macronutrients? Are they getting enough micronutrients? What’s happening with their vitamin and mineral levels? What’s happening with their choline levels? What’s happening with all of these different important micronutrients? And are they getting enough of them overall? And as we know, the vast majority of people that are dealing with or eating like a standard American diet, they’re very nutrient depleted, very calorically-dense and nutrient-poor. And so that is on the biochemical side what we need to look at.

And then the last area, and this is a really important one to really dig into, is psychological stress. And psychological stress is… I like to put it to those challenges that have occurred in the past that we can construe as trauma that may have blurred or scuffed the lenses through which we see the world. And so what this then does is it creates new perceptions and new challenges. And what often happens here in these psychological stressors, I’ve had numerous patients that had the loss of a child or loss of a loved one or some sort of major trauma with a family member or some sort of incident where they were a victim of a crime, for example. These psychological stressors take us out of a feeling of safety, and safety is the major driver from an emotional and psychological standpoint into biological control of inflammation. This is huge.

This is literally the concept of the polyvagal theory, if you’ve ever heard of this or if anybody has. Polyvagal theory was developed by Dr. Stephen Porges, a well-renowned PhD psychologist. And this entire concept of the polyvagal theory comes down to we have these different states that we can be in. The state that we want to spend the majority of our time in is when the brakes are pushed, when we’re doing well, when we feel like we’re recuperating and recovering from stressors. That state is called ventral vagal state. And from a psychological standpoint, we can only be in that state when we are feeling safety, psychological safety. This can be construed as biochemical and physical and emotional safety as well. But on the psychological safety side of things, that’s what drives us to be in that ventral vagal state, and that is where the emotional and inflammatory control piece really kicks in.

Then we have a state above this ventral vagal called sympathetic, which is the engaged state when we want it to be, when we’re able to engage ourselves to do something, push into a situation that’s a little bit more challenging. But at the top end of that state is where we get into fear and worry and areas where our bodies go into a sympathetic state for a prolonged period of time. And that’s where it can be really challenging to have biochemical function at a very great level.

There is a level above this, which is not a very common one, that we see as functional medicine practitioners, but if we’re talking to psychologists, they see it all the time, and that’s a state called freeze. And that is the dorsal vagal state. So where body goes into a physical shutdown or a bio… A physiological shutdown, excuse me. And that physical shutdown basically looks like vagus nerve is working, but emotionally we’re like a deer in the headlights. We just don’t know what to do. And these patients that are in this freeze state are dealing with severe depression, severe anxiety, potentially PTSD, potential major traumatic incidents.

So often, it’s these psychological incidents that take us out of that feeling of safety and push us into sympathetic or into this dorsal vagal freeze state that are driving these physiological changes to then occur, and take us out of a state where we’re able to fully control and take care of ourselves. Polyvagal theory I think is one of the greatest findings of our time, the greatest understanding how our feelings and what happens around us psychologically impact us and have a physiological impact on how we then function. So that’s a really important piece. I dig into that quite a bit in the second book.

Evelyne: Awesome. Thank you for sharing that. I’ve always been fascinated by it since I learned about it a couple of years ago. And I think it’s actually not that uncommon, but we do talk more about fight or flight and not as much about the freeze part. I’m curious, what are some of the best ways or the ways that you use to actually assess vagus nerve function? Is there a test?

Dr. Navaz Habib: There’s a bunch of tests. You’ve got the old book, which is awesome. The older book, the Activate Your Vagus Nerve is more of a beginner book, and there’s some tests in there, things like the bowel transit time test is a great one to implement with patients. I’ve got the palatine arch test, the say ah test in there as well. These are great ways to assess at a low level. But there’s no question the single best way to assess vagus nerve and autonomic nervous system function is through HRV, heart rate variability. That marker is, for me, the gold standard. It’s the one that we now with all the wearable devices that we have available to us can actually look at on a daily basis to see where we stand. Are we recovering well? Are we in more of a sympathetic state? Did we have a good sleep last night that then is keeping us in a situation where we’re able to push ourselves today?

And this is a tool that’s been utilized a lot by athletes over the last many years, but it’s something that needs to be looked at pretty intensely. So what HRV is is different than heart rate. Heart rate looks at the number of beats in a minute, counting literally the number of our spikes that are occurring in that minute time period. Heart rate variability, it’s looking at the number of milliseconds between beats of the heart, so our spike interval. That’s what we’re looking at. And then we’re comparing those intervals averaged over a period of time. That is how we calculate heart rate variability.

And what we’re looking for is variance. We’re looking for a greater variance. We don’t want heartbeat to look like a metronome because when it does, when it’s looking like a metronome, what it’s telling us is that our heartbeats are close enough together and so rhythmic that we’re likely just pushing the accelerator, just pushing the sympathetic nervous system to be on. We’re not slowing things down. Because as we push the accelerator, heartbeats come closer together, and as we push the brakes, the heartbeats spread apart. And so what we want is variability. We want to go closer and then further and closer and further, and that’s a good sign of variability and a good sign of autonomic balance that both the accelerator and brakes can be pushed effectively.

When they can’t, if the brakes are not working really well, we tend to have very low variability because those beats are staying rhythmically a certain number of milliseconds apart, and so that’s a sign that we can then use. So any patients that have Apple Watches, Oura Rings, WHOOP bands, Polar H10 chest straps, Biostraps, you name it, they’re all available, Garmin, Fitbit, all of these things are available now. Utilize that data point because that’s one that they’re interested in. That’s one that they are utilizing on a day-to-day basis. And if you can tell them, “I want to see this number a little bit higher than it was the last few days or the higher than your average, then that’s a day you can push yourself. But when you see it lower, don’t push yourself. Give yourself a chance to recover.”

And that way you can teach your patients on their own to really take control of what they’re doing or how they’re pushing themselves that particular day. Like if they wake up one morning and their HRV is sitting at 22 and their average is 40, don’t exercise. Don’t push yourself, don’t strain yourself. Go for a gentle walk, recuperate. And the next day, I guarantee number will pop up because you’ve taken a day to allow your body to recover properly because you haven’t overstrained yourself. But on a day when you’re in the 80s, wonderful, push yourself as hard as you want, go for a heavy workout because your body has recuperation and recovery capacity, and that’s really what HRV is signaling. If we have the ability to push the brakes, we have the ability to recover, and that’s really important to understand.

Evelyne: I’m curious about HRV measurements. So I think you’re wearing an Oura Ring. I just got one in January. It seems to be pretty low compared to say what Apple Health tells me. I’ve read that other people have had the same experience with Oura, and so I’m curious, is Oura your favorite? Do you find that something else is better? And do you have any ranges? I’m sure it depends on age and all these things, but curious about that.

Dr. Navaz Habib: There are so many variables to incorporate here. So Apple Health, Apple Watch, cool. Oura Ring, cool. I’m not going to put one above the other at all. There’s no better device than anything else. These are not the gold standard of measurement. None of these wearables are the gold standard of measurement. What they are is a trend marker. Look at them only for the trend that you’re seeing. Am I above my average or am I below my average? Because each of these wearable devices has a different algorithm, has a different sensor type, has a different area that they’re looking at to help understand what’s going on. There’s different ways of even measuring HRV. There’s RMSSD data, there’s time domain variants, there’s frequency variants, there’s different ways to do it. And all of these technology tools have very different things. So literally comparing an Oura Ring to an Apple Watch or to a Fitbit or to a WHOOP band is off limits. I would say do not compare device to device, period.

The other thing, don’t compare ranges. Find out what your average is. It usually takes about a month for any of your data points to become really standard to understand what your average tends to look like. And then the goal is try to be above your average as often as possible and then over time try to raise your average. That’s it. I’m never going to say your number needs to be 78 milliseconds. No, not at all. We don’t have specific numbers because there’s too many variables to consider when we’re looking at what these numbers are. There are averages. There are ranges, but again, it’s very, very different for each individual. So I would never ever look at a range and say, “You’re too low, you’re going to die.” That’s not the way that this works. It’s not a heart rate marker. Heart rate is very in a box. You want to be in a certain range, and if you’re outside of this range, it’s a sign of real dysfunction. What we’re seeing here is recovery capacity and what we want is increased recovery capacity compared to previous days. That’s the goal.

Evelyne: That’s very helpful, thank you. So how can we improve heart rate variability and therefore vagus nerve function?

Dr. Navaz Habib: So there’s a few areas that we can really dig into here. Obviously the number one is eliminating the number of stressors that are pushing on the accelerator in the first place, particularly those that are unconsciously pushing on the accelerator. So these can be the things like glycopolysaccharide and leaky gut that are driving internal imbalance. So this is where I would utilize tools like herbals. I’m a big fan of DFH products, so I use things like oil of oregano and GI Microb-X all the time to help eliminate gut issues and eliminate the bacteria that might be driving these opportunistic challenges.

I’m a big fan of FloraMyces. It’s a wonderful probiotic. I using the Saccharomyces Boulardii product to help push out the bad bacteria or any excess bacteria that are present there. These are wonderful tools. So helping to engage that gut function and get it optimized from a microbiome standpoint, that’s a massive win because we’re able to take that brick that seems to be sitting on the accelerator off or at least lift it off a little bit. What that does is it gives us a little bit more capacity to push on the brakes and let the brakes start to work more effectively.

On the psychological side of things, honestly, talk therapy is huge. Having the opportunity to just listen to what people are suffering from or listen to their story about what they went through, and for people just to be able to get their stress off their chest can provide that closure that’s required for them to be able to not use that as an excuse or as a challenge for what’s holding them back from taking really the next steps in their psychological health. So talk therapy, some form of therapeutic communication is going to be really helpful. On the psychological side of things.

Physically, good exercise, good recovery, wonderful. If they’ve had some form of concussion, brain injury, whiplash, getting some sort of therapeutic chiropractic physiotherapy, naturopathy care to help to manage the inflammation physically is going to be of very high value. Look into past physical trauma as well. Don’t just think of recency bias here because something that happened 20 years ago and their challenges started 19 and a half years ago, likely that physical trauma played an important role in the pathological process that occurred here in that breakdown process that occurred. So look at timelines, look at what that basis is.

But then if you say, “What can I do about it?” There are therapies that are proven to improve those physical breakdowns that occurred even if it was years ago. So things like vagus nerve stimulation, electrical vagus stimulation, one of my absolute favorites. I’m a big fan of electrically stimulating the cervical trunk of the vagus nerve. I’ve had some phenomenal results with my patients that I’m combining vagus nerve stim with a lot of the other therapeutic tools that I’m talking about here with you today. So that’s big.

And then supporting the emotional and psychological day-to-day stressors. So genetically, I’m not great with dopamine. I tend to break down my dopamine very quickly. Genetically, I’ve tested for this. And so things like DopaBoost are my absolute favorite. I’ll use these for myself and I use them with my clients as well. So these are great tools to help support the day-to-day, biochemical and neurochemical tools that need to be optimized. And so this is where we can look at things like organic acid testing or genetic testing to provide tools on how to manage those day-to-day stressors. Those four the big areas that I would talk to.

Evelyne: Great. And then we will dive into some more specific ways that practitioners can recommend patients also stimulate or activate the vagus nerve, but you talked about the electrical stimulation. How does that actually work? What is it doing when you apply that stimulation? What is happening?

Dr. Navaz Habib: So there’s different frequencies that have been tested for to see what the effect would be on the cervical trunk. And the best data that’s come out of this is particular frequencies of 25 hertz pulsed… Sorry, 500 hertz pulsed at 25 hertz. So it’s a very specific electrical frequency that you have the ability to increase the intensity of or manage the intensity of, tends to increase the function of the A delta fibers in the vagus nerve, allowing it to have a very strong afferent effect. So it increases the stimulation in the nucleus tractus solitarius and the dorsal motor nucleus of vagus, it’s the two main nuclei of the vagus nerve, the parasympathetic nuclei, they’re located in the brainstem. So there was fMRI data showing this activation in those particular neuronal tracts and those particular nuclei. And then a secondary biphasic response that occurs in the cerebrum actually shifting our state what seems to be very sympathetic to parasympathetic shift. So it activates the thalamus, which allows for us to get into sleep and arousal and mood and feeling and calm and emotion, regulation being the big piece here.

So what’s happening is an electrical pulsed field is physically activating the vagus nerve to become stronger and stimulate further, activating those brain areas that are required for regulatory processing. Essentially, we’re supplementing the brake lines of the body and allowing the brakes to do the job far more effectively when we do. So tools like the Truvaga, for example, I’m a big fan of. There’s options out there like Pulsetto or VeRelief. These are all great Vegas nerve stimulators. Where I would put my attention is where has the research been done and who has pioneered this? Because knowing what they’re doing and having actually researched their tools, it’s probably the best way to know that you’re getting a good therapeutic device with a good research backing.

Evelyne: Yeah, thank you for sharing that. And that’s actually how we met, was through an electroCore event. So I feel like for practitioners wondering what the devices Truvaga versus gammaCore, do you want to explain that really quick?

Dr. Navaz Habib: They’re very similar. The Truvaga device is a held wellness cervical stim device. My gammaCore device I’ve got in my backpack here. So these are the two options. So one is more of a wellness device, that’s the Truvaga, and that’s pretty much brand new. It connects via Bluetooth to your phone. It’s a great device for clients to kind of own and take. This is more of a therapeutic version, which is gammaCore Sapphire, and this guy is great for practitioners to prescribe in a therapeutic setting to their clients. So this has specifically FDA clearances for migraine, cluster headache, hemicrania continua, and recently PTSD as well. It did have a Breakthrough designation for COVID as well for breathing issues. So it’s been shown to have really positive effects in so many different conditions because it’s not necessarily… This therapy is not a cure for any particular condition, it’s a tool to facilitate that shift from sympathetic to parasympathetic and get the brakes working again really effectively.

Evelyne: Yeah, I know a couple doctors who use it in San Diego. More than a couple, quite a few doctors who use it in San Diego and really, really like it. I’m curious, in your practice, just if you have any stories to share specifically on the mental health piece with using a device like this where maybe you weren’t doing other things. I know in functional medicine we’re always working on all the areas at the same time, but do you have any where you just attribute the use of electrical stimulation to improvement?

Dr. Navaz Habib: Yeah. I’ll say there was a really good one. I was working with a very high performing former world figure skating champion years ago, and this was when I first… I hadn’t even utilized it. I hadn’t really been introduced to the technology very much at all at that time. And we started doing some vagus nerve exercises with this patient. We affected gut health and did a lot of particular things. But we really hit a plateau after about a month and a half where she just was not experiencing any of the positives that I would be looking for and generally was getting with a lot of the other clients. With this particular client, we then added in the vagus nerve stimulation piece, I believe it was at month three or month four of her therapy, and the results just automatically started happening again. We really shifted.

And what was really important about her case to look into was she had multiple concussions. So she was a figure skating champion, which means that she was a figure skater, and this was in the 80s, so she had multiple falls on the ice that were not well diagnosed and well-treated as concussion. It was one of those dust yourself off and get going and not realizing that there was an effect. So she actually had somewhere between 8 and 12 concussions previous to any of her health struggles really kicking off. In addition to this, a huge piece to her issues was body image challenges because she had to present herself on the ice looking a certain way. And so there was a lot of anorexia and bulimia as a part of her struggle. And so this was a major piece to her journey and I think that’s where a lot of mental health issues obviously will show up in that physical form.

And the last area, the last major stressor that she had experienced that caused quite a bit of anxiety and depression in her case. She actually had lost a child as well. She had a set of twins and only one made it unfortunately. And so there was some unresolved psychological trauma and there was some emotional guilt and depression linked to that. And with that particular case, it was this therapy that really pushed us over the edge to getting things resolving in a very positive way.

We had tons of wonderful case studies, one that literally today told me that she had these benign tumors present on her liver for years after her daughters were born and then the year prior to versus the year after getting started on a physical vagus nerve therapy plan with stim and a few other strategies because as you said, we can’t do one thing as functional medicine practitioners. Her tumor has literally shrunk down to were not being able to be seen on ultrasound. She had two of them and they’re both shrunk down. They literally have been unable to relocate these tumors on her liver, which was crazy as well. Yeah, these were cool ones that I’m happy to share with you as well.

Evelyne: That’s really interesting. And we talk so much about the gut-brain connection, but I don’t hear much about the liver-brain connection or all the other organs, right?

Dr. Navaz Habib: Totally. The liver piece I feel is heavily overlooked. We know there’s 500 to 1,000 different functions that the liver is performing at any given time. It has a ton of nutrients in it. It’s constantly filtering out the blood from the intestines through the portal veins. It’s producing bile, it’s eliminating toxins. The bile synthesis piece and the subsequent gallbladder function and gallbladder control of sending out the bile into the intestinal tract is heavily modulated by vagus nerve. And one of the more common things that I hear is, “I had my gallbladder taken out, I had gallstones, I had this type of issue.” It was a smooth muscle of the gallbladder that was unable to be pushed because your vagus nerve likely didn’t send signal strong enough, and that allowed for the gallbladder to remain in a dormant looking state. And so the bile salts that were present crystallized and became bile salts and bile stones. And these gallstones then lodged themselves in the bile duct and that was the source of the challenge.

And so cholecystectomy is a major, major surgical process that I think is a direct sign of vagus nerve dysfunction because if you’re not able to send that signal to the gallbladder to pump out the bile effectively, you’re not eliminating toxins, you’re not producing the bile and allowing for the absorption of fat effectively. And so that’s going to have a massive effect on the gut health piece. So how all of these pieces unite and work together in such an important synergistic environment and just… It’s almost like a symphony with one or two pieces that are not working well, it’s going to throw the entire symphony off. We can’t just say that it’s one area that’s not working. It’s that uniting force that is not working in this particular case. And so I’m a big fan of looking at every single area, but detoxification and liver function being very high on the list.

Evelyne: Super interesting. My brain is churning now. I have another question that I’m sure people are wondering about. We just talked about the electrical stimulation, but there are also things that patients can do at home to improve heart rate variability to improve vagus nerve function. What are your, say top three or four, that people can do that don’t take a lot of time that are easy to implement?

Dr. Navaz Habib: Everything vagus nerve-related in terms of improving its function comes down to your breath. The breath is the key to vagus nerve optimization, period, end of statements and end of sentence, end of the book on the topic. It comes down to are you breathing effectively? So the breath needs to be diaphragmatic, it needs to be slow, and it needs to be focused on the exhale. It also needs to go through the nose. Nose is our breathing tube, mouth is our eating tube, and we have a backup if we need it, but it should not be utilized, effective all the time. So we should be breathing through our nose shorter but deeper inhale. Feel free to do a bit of a breath hold and then a longer exhale, everything diaphragmatic breathing into the belly, letting that air come into the areas where we’re getting fulfilling of the lungs, allowing for the diaphragm to do its job.

We often think of the diaphragm as simply being this muscle that allows for the vacuuming effect to bring air into the lungs. The diaphragm is intimately connected to the abdominal region as well. And so when the diaphragm is doing its job of creating that vacuum above in the thorax, it’s also creating a massaging movement in the abdominal walls and the abdominal organs. And so that is a major trigger for that peristaltic motion to occur. It’s a major trigger for liver detoxification and pumping action to occur. We’ve been taught not to show our bellies. We’ve been taught and trained that when we take a deep breath, we do it with our chest. We all have these tight upper back muscles and terrible posture because of our cell phones and laptops, but what we’ve been taught is entirely incorrect. We should be breathing primarily with their diaphragm in our belly as the major driver.

Simply watch a baby breathe. You’ll never ever see their chest rising. You’ll always see their belly rising and falling. That’s natural breathing. We’ve actually trained ourselves out of that. And so when we teach ourselves to breathe effectively again through our nose, using our diaphragm, and longer exhales, we’re actually then going to implement vagus nerve activation. That’s huge to this entire puzzle. As we breathe in, we actually are bringing our heartbeats closer together. So an inhale is actually a very sympathetic activation. You can imagine a cold shower hitting you on the back of your neck. You’re like, “Oh my god, what’s happening?” You tighten up, you take a breath in. That’s a sympathetic reaction that occurs. When we breathe out. We often say, “Take a deep breath.” We take that sighing, calming breath. That exhale is driving a parasympathetic push.

So we’re constantly doing this dimmer switch up and down, up and down, up and down. If we can pull that dimmer switch slightly down a little bit further because we’re in that exhale phase for longer, we’re then going to on average be in that more parasympathetic state more regularly and we’re going to be more regulated able to come into that parasympathetic state more easily as well. So that’s number one. It comes down to your breathing patterns and your breath control being number one. Number two, nutrition piece. Not just about taking in enough nutrients and not bringing in the toxins, but really looking at a couple of those narrowed down areas of nutrition. We are heavily in choline in the North American diet. Choline does not make its way in, and acetylcholine is the neurotransmitter utilized by the vagus nerve. In order to produce acetylcholine, we need choline and we need acetyl-CoA. Acetyl-CoA is driven by mitochondrial function, mitochondrial optimization.

So as a mitochondria function well because we have enough B vitamins, because we have the cofactors that are required like the carnitine and lipoic acid and B1 and B3 in particular, getting those nutrients in to ensure that we can go along that pathway of glycolysis and Krebs cycle, allowing the mitochondria to do their job. We’re going to have enough acetyl-CoA being produced to allow for mitochondrial function and for acetyl-CoA production. And then choline, 90% of our diets are deficient in. So getting that choline in through some dietary or supplemental source, allowing for that combination to then be present within our bodies and for acetylcholine to then be able to go out and do its job through the vagus nerve is of utmost I importance.

So I would highly recommend diets be looked at and that we have certain foods and supplemental tools to address that phosphatidylcholine in particular. I would avoid the choline salts, the choline bitartrate or the choline citrate, avoid those two simply because they do increase TMAO markers in the gut, which is linked to cardiovascular disease. Not causative, but correlated. So definitely one that I would stick away from, but phosphatidylcholine or CDP-choline are great options for getting that choline level up without having that TMAO effect in the gut. Okay.

And then the last one, number three, adding in some sort of stress management or biohacking tool that’s linked around the breath. So yoga, for example, is a great tool because it’s difficult postures while working on your breath in that moment. Or cold plunges if people don’t have Raynaud’s or some other challenge. A cold plunge is wonderful because you get in and you’re putting yourself physically into a tougher position to breathe effectively, but you’re teaching yourself to breathe effectively while under stress. So a parasympathetic breath while in a sympathetic dominant state. It’s a great way to help teach yourself to do that.

But again, it all comes down to the breath and that’s key to everything vagus nerve-related. It’s not just about stimulating and moving on. It’s not just about an anti-inflammatory diet and moving on. Teaching ourselves to breathe, something that we do something between 18 and 30,000 times per day. Doing that efficiently, doing that effectively, that’s what we need to focus on because that’s the real needle mover when it comes to HRV and vagus nerve function.

Evelyne: Super helpful. Thank you so much. What about things that I hear about like humming or gargling? Are you a fan of those?

Dr. Navaz Habib: Yeah, these are great. Humming, gargling, chanting, singing, auditory listening therapy the something that’s very heavily linked to the polyvagal theory in a really cool way, all of them come down to breath and breath control. So I get into a lot more of them in the new book with some science backing, but with humming, chanting, gargling, singing, what we’re doing is we’re activating the laryngeal and pharyngeal muscles at the same time, which allows for motor control plus all of those things. Humming, chanting, gargling, singing happen when in long, prolonged exhale. So the breath control is a massive piece. So combining the breath control with the motor activation of the laryngeal and pharyngeal muscles gargling, humming, chanting, singing, will have exactly that effect.

That’s what Om is built around, the tradition of humming Om and that frequency of vibration with the long prolonged exhale. That is actually linked on a physiological basis to calming and to vagus nerve activation without having been known to be linked to vagus nerve activation. But Gregorian chants, very similar tool that’s been used in a very similar pattern. Every religious practice has some form of humming, chanting, hymns, things like that, that are involved in creating that vibration piece in the throat that is going to link with a long or prolonged exhale. And together that’s going to have a very calming emotional effect. So that’s definitely an area that I would put into practice with different people.

And for different people, it’s going to be different things. Like for my kids, I’ve got two kids, one that’s seven, one that’s three, it’s chaos before dinnertime. I want them to get into a rest and digest state before we go and sit down for dinner. We’re often rushing around, got this activity or that activity, or the kids are just running around outside. What we want to do is get them into a state where they can actually digest their food effectively. And so humming before a meal, for example, gets everybody laughing, calms everybody down, really wonderful tool. So we pretend that we’re bees and we buzz around like bees for 30 seconds before the meal starts and everybody’s laughing by the end of it. It’s wonderful.

Evelyne: That’s so cool. It’s interesting what you said about different religions and how they do this. Even before you said that, I was thinking we’ve always known, haven’t we, as humans. We’ve always known what to do. We’ve just gotten away from that. I’m curious too, you said with the humming like a bee or buzzing like a bee, you do it for a certain amount of time, but with these practices, do you recommend doing it multiple times a day, once a day, multiple times a week? What’s the research on that?

Dr. Navaz Habib: I’m personally a fan of daily practices. I think for a lot of people that tend to have really good health, they’ve implemented these on a multiple times per day basis. They’ll often catch themselves and take a breath by themselves or be able to know internally that they’re dysregulated and make a change accordingly. They’ve trained themselves to be able to do this, and so it’s something that we have to train our clients to have to do on a more regular basis. So even something like a basic 4, 7, 8 breath, a four-second inhale, seven second hold, eight second exhale breath is a great tool for anybody who’s feeling anxious in the moment to be implemented on an as-needed basis, doing between four and eight of those in a situation that’s a really wonderful and very, very strong anxiety reducer. It’s a great tool for just overall mental health. Something like that can be implemented literally six times a day if it needs to be. So depends on the practice, as long as there’s some level of regularity, but it should be a daily practices at the very minimum, my requirement.

Evelyne: Great. And before we wrap up, I just have one more question. Since you mentioned that Nature article, can you tell us a little bit more about it and just some of the advances in vagus nerve research? And I’m particularly interested in the inflammation piece, especially because now finally, we’ve known about the psycho-neuro-endocrine-immunology for a long time when we’re in this field, but I feel like now people are realizing more and more that some mental health issues are based on inflammation, it’s not the only thing, but can you talk more about that?

Dr. Navaz Habib: Yeah. The role of the vagus nerve is to communicate with the immune system and the immune cells that are present in each of the organs that it connects to. And so what needs to happen is those immune cells are actually the prime connecting point to the external world. So we’re sensing the presence of lipopolysaccharide or other toxins that are entering the body, and those immune cells are the ones that are doing it. It’s primarily these tissue-resident macrophages that are present in each of these organs. So in the liver, it’s the cup cells. In the skin, it’s the Langerhans cells. The brain is the microglia. In the gut, it’s the intestinal macrophages or the gut-associated lymphoid tissue. These cells are sensing what’s happening and then sending a status update through the vagus nerve.

What this Nature article goes into is identifying the exact neuronal type and the connection that it has to send those inflammatory signals up to the brain to actually have that information processed and sent down. I’m still deciphering quite a bit of it because I haven’t fully released the article. It was like a pre-print release that they did, but it’s a very in-depth one. That said, they’ve identified specific neuronal types, specific neurons in the nucleus tractus solitarius, nucleus of the solitary tract, which is the afferent branch, that 80% of vagus nerve that comes up, specific neurons that are constantly taking in that inflammatory signature information and allowing for that processing to occur so then it can send appropriate signals down through the vagus. This is a revelation finally in the research to prove that this is working and how this process works. So I’m definitely going to be digging into this one quite a bit more.

Evelyne: Awesome. And we’ll link to it in the show notes. I just have three more questions for you just quickly that we ask everybody. What are your three favorite supplements that you like to take?

Dr. Navaz Habib: Personally, I mentioned one already. The DopaBoost is a no-brainer for me, keeps me driven, keeps me working. I also do take… I’ve got it sitting here with me, my twice daily Multi, which I love as my daily go-to. And I use a nitric oxide supplement to help with resilience and blood flow as well. I know Vascanox is a great one as well. So these are my top three personally. And then a couple other ones, probiotics and Omega-3s as well.

Evelyne: Awesome. And I think I know the answer, but what are your top health practices to keep you healthy and resilient and balanced?

Dr. Navaz Habib: Number one is going to be a regular breathing practice. Generally practice before I go to bed helps me get into a state where I can relax after the chaos of running a business and having a family and the day-to-day life that one that’s in my situation tends to live. So that is a huge one. I will either go to the gym and do some weight training or ride my bike about three to four times a week outdoors, depending on the weather. I’m not in wonderful San Diego, so I’m jealous of your weather patterns. I’m in Toronto, so we have like a five or six month window in which I can actually go outside and enjoy that bike time. So I will do my best to do that. But regular exercise, regular movement are massive when it comes to mental health function and just keeping myself stated. And then I’m at a standing desk that I’m not currently standing at, but I try to use that on a daily basis as well, not to sit on my butt for too many hours per day. So those are my big three, for sure.

Evelyne: Wonderful. And Navaz, what is something that you’ve changed your mind about through all of your years in practice?

Dr. Navaz Habib: I think the biggest thing that I’ve changed my mind about is that the breath matters more than even diet does. What’s interesting is we’ve… Food is sexy. We talk about food all the time. We talk about nutrients all the time and follow this diet, follow that diet. It’s got to be carnivore or keto or vegan or paleo, whatever it is. We’ve talked about that and there’s been so much debate on which diet you have to follow and which set of rules it is that you have to follow. And who’s talked about breathing patterns, who’s talked about breathing practices and becoming efficient and effective there in something that we do not three times a day or four times a day, but 30,000 times a day?

Evelyne: Great point.

Dr. Navaz Habib: Something that we need to really focus on. So for me, it’s the importance of the breath is what I’ve changed my mind on for sure over the last little bit.

Evelyne: Awesome. Thank you for sharing that. And thank you for all of the amazing information. I really enjoyed our conversation today. Where can practitioners find more about you?

Dr. Navaz Habib: You can check me out on any social platform, Dr. Navaz Habib, and then check out the book Upgrade Your Vagus Nerve. It’s available everywhere. I’m at conferences all the time, so you might be able to pick one up, but I’m all over the place. So wherever you see anything vagus nerve-related, I’m usually not far behind.

Evelyne: Amazing. Thank you so much for tuning into Conversations for Health. Thank you again, Navaz. This was wonderful. Check out the show notes for any resources from our conversation today. Please share this podcast with your colleagues, follow, rate, or leave a review wherever you listen. And thank you for designing a well world with us.

Voiceover: This is Conversations for Health with Evelyne Lambrecht dedicated to engaging discussions with industry experts exploring evidence-based, cutting-edge research and practical tips.