Your brain is actually the centre of a vast network of nerves – a complex system that extends throughout your body. Scientists refer to the brain and the spinal cord as the central nervous system and everything else as the peripheral nervous system.
The peripheral nervous system is a bi-directional information highway, sending information from bodily organs to the brain and operational instructions from the brain back to the body.
Some nerves carry information from our sensory organs — such as our eyes, ears and skin. These help the brain to build a detailed perceptual picture of the world around us. Scientists call this exteroception.
But we also have an often overlooked set of nerves which deal with interoception — the sensing of the internal state of the body. Some of this perception of bodily state (such as pain) is just as clear and sharp as the sensations of the outside word. But we also receive interoceptive nerve signals from our visceral (internal) organs which tends to be less sharp but in no way less important. Probably the most important interoceptive nerve in our body is the vagus nerve which connects all of these visceral organs to the brain.
The sensations we receive along the vagus nerve tell the brain about the state of these organs; and signals from the brain control the function of these organs – everything from the beating of your heart to the digestion of food in your stomach and intestines to the filtering of blood through your liver.
The vagus nerve forms a major part of half of the interoceptive nervous system called the parasympathetic nervous system. The other half is called the sympathetic nervous system. These two halves work together to maintain bodily homeostasis — which refers to the body’s natural equilibrium state.
The sympathetic nervous system speeds up the body and becomes more active during stressful and dangerous situations; while the parasympathetic nervous system relaxes the body and becomes more active when we are in safe situations so that we can effectively regenerate and heal. Homeostasis is the balance between these two forces and is crucial for survival in the short term, and health and well being in the long term.
What we feel from our interoceptive nervous system is often vague compared to our exteroceptive perception. This is actually an important evolutionary adaptation. If our interoceptive perceptions were as loud and vivid as our exteroceptive perceptions, all we would ever hear would be the beating of our hearts, the air rushing into our lungs and the gurgles of our digestive system. These sounds would overwhelm external noises so much that we might not notice that sabre tooth tiger sneaking up on us.
But these sensations are nevertheless very important to survival. So the brain solves this problem by turning the sensations into broad emotions and vague feelings. This filtering can sometimes lead to confusion however — for example when you get short tempered because you’re hungry.
And so, one of the consequences of this evolutionary adaptation is that when your vagus nerve is reporting a problem or has a problem with its own function, it’s not always easy to know. This uncertainty makes it a challenge to recognise when there might be a problem. Here are a few tips on what to look out for — but remember, these are just guidelines. If you recognise any of the things below, it doesn’t necessarily mean that it’s caused by an issue with your vagus nerve, it just means you might benefit from trying out a few things.
Vagus nerve health (sometimes referred to as vagal tone) is worth improving even if you don’t experience any of the specific issues below. Like sticking to regular exercise and a healthy diet is good for you even if you don’t feel like anything in particular is wrong.
1. Mood and Memory
OK, mood changes can be caused by a lot of things, so just because you experience some, doesn’t mean you have issues with your vagus nerve. But emotions don’t occur in a void and like we said earlier, they are not only caused by external, environmental factors, but by the internal state of your body.
If you’re experiencing unusual and persistent mood swings, it could be a sign you have some underlying health issues.
The vagus nerve connects to all your visceral organs, so if the integrity of the vagus nerve declines, it hinders communication between the brain and these organs. This can be caused by and cause degrees of dysfunction in your organs. Early stages of this affects mood because, in a way, you feel that something is not quite right. So you may have inexplicable feelings of anxiety, sadness, tension, bouts of anger or general feelings of discomfort.
In some cases, it has been shown that dysfunction of the vagus nerve can also affect memory and cognition. Scientists still don’t fully understand the mechanisms, but studies have found solid links between good vagal tone and good mental health.
2. Energy and Blood Circulation
A lack of energy, feeling of weakness or fatigue, dizziness or fainting can all be signs that your heart and circulatory systems (the blood vessels) are not responding well to the oxygen and energy demands that are being placed on them. Our hearts actually respond from beat to beat to changes in the needs of the brain and body; and blood vessels expand and contract to regulate blood pressure. How well your heart adapts can be measured by your heart rate variability (HRV). You can learn more about this by reading our earlier post.
Experts are increasingly using HRV as a better measure of health and fitness than a simplistic average heart rate. A low HRV can be indicative of a number of underlying health issues.
As heart rate is highly regulated by the vagus nerve, it is one of the most useful indicators of vagal tone. Improving your HRV using diet and exercise or vagus nerve stimulation is one of the best things you can do for your long term health.
3. Digestive Issues
Your guts are like a second brain, containing more than 100 million neurons (or brain cells). Signals from these cells are often the drivers of the mood changes we mentioned earlier.
The vagus nerve is the main link between your digestive system and your brain. Signalling from the brain along the vagus nerve coordinates the digestive process and dysfunction in the nerve hinders communication. This can lead to an array of problems such as frequent indigestion, slow emptying of the stomach, heartburn, irritable bowels or weight gain.
4. Chronic Inflammation
Inflammation is part of your body’s natural response to injury or infection. This is highly controlled by brain signalling along the nervous system and the vagus nerve is one of the primary pathways which signal to the brain the need for an inflammatory response.
The bi-directional communication both triggers the start of an inflammatory response and regulates the amount of inflammation that occurs. However when these neural circuits perform ineffectively, this can lead to excess inflammation. This in turn can lead to diseases such as arthritis and in extreme cases, as we have seen recently in the immune response to coronavirus infections, uncontrolled inflammation can become life threatening.
Studies show that stimulation of the vagus nerve can ease the suffering of arthritis and may help improve immune system health.
The body’s inflammatory response has been highlighted by a number of recent scientific and government reports as a primary driver in age related decline in health.
5. Difficulty swallowing
The vagus nerve plays an important role in the swallowing process. Although we take swallowing very much for granted, it requires a complex series of coordinated actions.
As you swallow a number of reflex actions occur which shut the nasal cavities and open the oral cavities, followed by esophageal contractions which push down into the stomach. The vagus nerve plays an important motor and sensory role in this process, working in concert with a number of other cranial nerves.
Dysfunction in the vagus nerve can make swallowing difficult and even dangerous. A small mistake can result in food passing into your lungs rather than your stomach. If this happens, impulses from the vagus nerve induce reflexive coughing to try to expel the food or drink from the lungs.
If you recognise any of the above issues, you may find great benefit from vagus nerve stimulation. Severe or sudden cases should always be discussed with a medical practitioner, but we all sometimes experience these changes to a greater or lesser degree. If they are mild but noticeable, simple lifestyle changes can help.
At vagal.com, we believe that electrical vagus nerve stimulation can help support these lifestyle changes. A growing body of recent science is showing that electrical treatments (sometimes called eletroceuticals) can in many cases be more effective than pharmaceutical interventions and carry almost no side-effects. However, electrical nerve stimulation shouldn’t be seen as a panacea. It shouldn’t be the only thing you do and it often works best when it’s used in conjunction with other lifestyle changes.
Improving vagal tone using direct electrical stimulation can often make it easier to engage in other activities, such as regular exercise and healthy sleep patterns, which in turn help strengthen vagal tone, leading to a virtuous cycle of better health.
Stay tuned for tips about other things you can incorporate into your life to improve vagus nerve health.
Discussions (2)
excellent article
I HAD NO PROBLEM TILL I HAD NEDDLING ON MON. BY WED. COULD NOT SPEAK OR DIGEST , NEDDLING WAS DONE ON LEFT HIP TO EAS BURISIS AFTER LEFT KNEE.REPLACE MENT
I HAD NO PROBLEM TILL I HAD NEDDLING ON MON. BY WED. COULD NOT SPEAK OR DIGEST , NEDDLING WAS DONE ON LEFT HIP TO EAS BURISIS AFTER LEFT KNEE.REPLACE MENT
It sounds like the cat chewing the cable has caused a break in the connection which would explain the lack of sensation and needle behaviour. You can try soldering the wires to fix the connection the new replacement. We did select a heavier duty cable on the new version but I can confirm it wasn't tested on cats.
my son purchased the vagus nerve device for me about 3-4 years ago.... i see that the ear clips and wire have changed and appear to be more durable. my cat just chewed the wiring ( 2 thin ones.. one blue , one white) so i was wondering if he can solder it to repair? also i have 537 uses .. and no longer feel the tingling on my ear part like i did at first... does the device lose strength? must i use the wax each time for it to work effectively? when i try to up the strength, the red arrow moves to just over the halfway line and then falls back to zero. now it remains at just below 1/2 way but i don't feel the tinging sensation... thank you for answering all my questions~
How do I know if my vagal nerve is under or over acti e . I get tachyacardia and anxiety . I have a lot of digestive issues. IBS . Bloating seems to bring on the tachycardia .Thank you bonnie.10@homail.com
I have a vns implant tor epilepsy. The battery life may be getting low. What symptoms do I look for? I have been having night sweats for the last month. Could these be a sign of battery low?
Great, Reliable and very informative! I was diagnosed with a hiatal hernia and gerd 5 years ago. Cause: Inflammation and Low stomach acid. Currently, low Cortisol and high histamine levels. Disruption to my Vagus nerve! Any suggestions for repair Thank You.
Where in New York State or elsewhere Vagus Nerve CT scan available?
I have herniated discs at the cervical region and at the thoracic region. I have vagus nerve damage. Dry mouth and gastrointestinal issues. I am not sure where they are coming from, cervical or thoracic. Hard to eat anything with nausea and vomiting and digestion issues. Your thoughts?
Hi Cheryl, Try a parasite cleanse & I would recommend CBD @leaflifelondon. hope that helps
Ask your GP to refer you for scans of the area in question. Because the nerve runs through so many parts of the body this will help determine who is best to treat it. I recently had a paraganglioma removed from my neck so this was managed by an ENT.
How do you know when to increase the intensity?
Shortly after my first knee replacement surgery in 2012 during which l suspect the tube used to incubate me was too large because l could barely speak for weeks and had difficulty swallowing, was kept in a nursing home for three weeks after they assessed that l had a stroke even though aced their cognitive testing. My potassium levels crashed during this “stay” and now am on prescribed supplements for life. From the time l was released, l noticed eyesight deterioration and shortness of breath, which a specialist said was caused by trigeminal neuropathy. My GP has ordered various tests over the years with no determination of why shortness of breath is literally the norm for me. This year chronic dry cough and frequent asthmatic responses have joined my condition. Could my vagus nerve have been injured by the breathing tube? P.S. l have been dual chamber pacemaker dependent since 2006 due to loss of independent activity in my lower chamber, but heart function is good and four moderate leaky valves have changed very little since 2006. Again, wondering if vagus nerve could have been injured by breathing tube in 2012 and initiated the trigeminal neuropathy issues?
What type of Doctor would diagnose a problem with the Vagus nerve?
I'm a child/adult psychiatrist interest in more research-related as well as cost info on your product. Please send what you might have available. Thanks
Any relationship between vagus nerve /damage and small fiber neuropathy and autonomic neuropathy. I’ve been diagnosed with both plus gastroparesis. I’m now in advanced heart failure. It’s like something is attacking my body but nobody can figure it out. Not even the cause of the heart failure. It’s not hereditary. I would appreciate any advice you have. Cheryl
This is all very interesting. My relationship with IBS always follows courses of antibiotics taken for my frequent attacks of UTIs. My last attack I took four different courses of antibiotics leaving me with stomach ache sounding like IBS m I am 85 years old, I cannot take buscapan as I use eye drops for Glaucoma. At the moment I’m taking pre probiotics, recent peppermint oil capsules. Can you advise further please.
I am interested in ordering
I had facial shingles 6 years ago. It initially caused a uveitis, with a minimal skin rash. But I was left with tinnitus that is permanent; sometimes with nausea. It’s interesting reading this because a year later I lost my voice for 3 months and my hearing. And periodically felt it flared up, feeling unwell with above plus flu-like symptoms. Don’t know whether it’s connected, but several episodes of fainting since. Also recently investigated for Brugada pattern. Well in between, but mighty curious! This article makes it all seem more connected. Thank you
Tell him to begin day with diaphragm belly breathing . do 3-4x day. Also start day with cold cloth at back of neck puts body in rest digest. Also do eye exercises like salamander look clear to right center left. Kept repeat when you start to yawn or swallow getting better. Sing loud Gargle Lower stress in life. Seek happy.
My husband has had several vasovagal syncope episodes,over the last five years. 4 of them seem to have been caused by eating a plate of food. He begins to feel full and unwell - then passes out,with eyes staring and face shaking(he is not aware of anything). When he comes round he is then sick! The first time this happened he ended up in A and E. How dangerous is this?
I cannot get the timer to come on. I get pictures of the ear and the clip. The clip is secure to the targus but repetitive trys to push the button do not turn it on
You can change the session duration by pressing the blue joystick up or down when you see this screen
How do you adjust the duration on the tVNS unit? Thanks
I asked about AB62. It's the same as 862? When you mention "using the same electrode clip" do you mean one side of the two sided clip? I haven't paid much attention to which side I'd been using. I'd probably need to put a mark on it to know which side I've been using.
It sounds like you have a build up of electrolysis on your electrodes that is impeding the flow of stimulation. This will naturally occur during usage and is easy to fix.The electrode surfaces are made of sterling silver so can be cleaned with silver cleaning or most mild detergents. Once you return the electrodes to like-new condition and the impedance is cleaned off, the device will be able to reach maximum intensity again.
Hi, My VNsS, purchased here, has malfunctioned after approximately 486 sessions. The timer/graph page comes up, but will not start when I click the button. Trying to change parameters doesn’t work either. This is a very expensive machine. Is it possible I could send this vm one back and you could discount the price of a new one? I am leaving town soon so would like to have a new one before I go, so your prompt reply is requested. Thank you,
My son diagnosed with visual snow, POTS, EDS, depression, anxiety and other autoimmune diseases. We are excited to try this as alternative treatment as conventional doctors have nothing to offer other than prescribing meds with severe side effects.
Heart patients are at risk for vasovagal syncope. I know that the vagus nerve slows down the heart in such cases and that some heart patients faint or die while on the toilet. What is the specific trigger for such cases of vasovagal syncope. Is it constipation or just the act of straining?
Under what conditions are they dangerous? Used a TENS to stimulate my vagus nerve and am worried I could have damaged it. I used same settings (200Ms / 25hz / Normal mode / 13 minutes)
I've lived with a severed Vagus Nerve (right side) for twelve years. This article enabled me to better understand several of the symptoms. I was unaware of the cognitive, voice, mood, and cardiovascular effects. Knowing more is a mental boost. Thank you!
The electrode is clipped to the tragus
Electrode put under the left ear or on its tragus?