Vagus Nerve Stimulation: Dallas, TX's Solution for Long Covid

What is vagus nerve stimulation?

Vagus nerve stimulation is not new. It was identified back in the 1920’s as a nerve that can regulate the parasympathetic nervous system to release Acetylcholine neurotransmitter. In general, the autonomic nervous system is made up of these two opposing sides, kind of like a Ying and Yang:

Sympathetic nervous system gets our body ready for fight or flight – faster breathing, faster heart rate, large pupil to let more light in, increased stress hormone cortisol released, and increased blood flow to the brain to be clear headed.

Parasympathetic nervous system controls digestion, a sense of wellbeing, and relaxation. When your body is under parasympathetic control it tends to heal and repair.

Between the tone of these two systems, they regulate the rest-and-digest, tend-and-befriend, and fight or flight responses. We want to spend most of our time under parasympathetic control.

Ideally both systems will oppose each other in such a way as to create homeostasis or a equilibrium in your body. Long COVID disrupts this. It causes autonomic dysregulation. One of the ways we treat this is with a stellate ganglion block (SGB) which downregulates the sympathetic nervous system. This may not be enough for some patients suffering from long covid to fully recover. Perhaps adding increased tone to the parasympathetic nervous system via external vagus nerve stimulation can also help. This may recreate the equilibrium our bodies need to fully heal.

Have you heard the expression, “fake it till you make it?” That’s what the vagus stimulation does. We need to help the parasympathetic take control again. The parasympathetic system is running too low in long COVID. Low tone means virtually no healing. In long COVID, you are 99% in high sympathetic tone. Since our bodies are not designed to be in this state 24-7 many of the symptoms develop as a result of this. Think what your car would be like if you ran it nonstop in 1st gear. On roadways and highways. That’s what your body is being put thru day after day. Yes anosmia and parosmia are important to treat but the brain fog, fatigue, palpitations/chest discomfort are also part of this. Ideally we spend 99.9% of the time with parasympathetic tone normal or high and 0.1% sympathetic tone dominant in required situations. “Nearly hit another car or almost got hit yourself”. Crazy dog barking at you. See a large hornets nest. Etc

Where do I place the ear clips?

Lucky for us, it is easy for us to stimulate the vagus nerve on the surface of the ear. The simplest way to accomplish this is at the tragus of the ear. The idea is to stimulate the vagus nerve through the area surrounding the external ear opening called the meatus. The tragus is an ideal spot.  Alternatively, you can use the cymba concha or the concha cavum but it’s more difficult to get a clip to stay on in those areas.  It is also less comfortable than the tragus. Do NOT stimulate the ear lobe despite many YouTube videos and entries on Google. In 66% of people with long covid, the vagus nerve has been found to be involved. With imaging, it was shown thickened. Parasympathetic tone has been found to be lower than in those without long covid. Part of the autonomic dysfunction can be treated with this.

This stimulation can be accomplished using an inexpensive TENS unit like the TENS 7000. We like this unit because it has adjustable pulse width and frequency, but any unit that has these features will work.

Please only stimulate one ear at a time. Remember you must use 2 electrodes to complete the circuit. We recommend placing both electrodes on one ear. If you are not able to, you can place one pad on the neck or upper back area with a pad instead. Stimulation won’t work with just one lead/electrode. Do not jam the clip into the external ear/auditory canal.

Which Ear Is Better / Safer To Use?

With low intensity stimulation, it is likely safe using both ears. However, the left ear is less likely to cause bradycardia or slowing of your heart. Limit stimulation to 30 minutes until you know how the stimulation effects you. Check hear rate during right ear stimulation.

You will need a unit that you can set the milliamps (mA), pulse width, and frequency. Some units come with selectable “programs “and are preprogrammed for certain actions setups only. Those are not good for what we want to do here. Those units are for Electric Muscle Stimulation (EMS) even though they call themselves a TENS unit. There are also dedicated vagus nerve stimulators available.
We like the "TENS 7000" because you can adjust the frequency, pulse with/duration of pulse, and intensity and its inexpensive, under $40 from most vendors. You can find it on Amazon or being sold on the web. You will also need 2 ear clips with a 2mm female attachment.

Do NOT use if you have a pacemaker or defibrillator, are pregnant, or have a sick heart

How does Vagus nerve stimulation (VNS) work?

This non-invasive electrical stimulation of the “somatic” (i.e., external ear) afferent branch of the vagus nerve activates both “visceral” and “somatic” vagal projections in the brain and increases activities on the parasympathetic nervous system.

What are the TENS parameters that should be used for External Ear Stimulation?

Some starting TENS parameters

  • Normal or continuous mode, do not use burst or EMS or any other mode please
  • Use the left ear. Left ear spares the heart, so it’s the safer ear to use. If you keep the intensity low, it’s likely safe to use the right ear as well.
  • Frequency 25Hz (range 15-30 Hz)
  • Pulse width 250 microsecs
  • Intensity on TENS 7000: between 1-3.
  • Once a day for 15 – 30 days.

Tips and Tricks

  • Make sure one lead clip is on the tragus.
  • If you don’t feel any tingling at all, try wetting the ear areas including tragus with some tap water or saline eye drops
  • Can change placement location for the lead NOT on the tragus.
  • Can switch the leads, change red to black and black to red.
  • Can try a different clip type. I personally prefer the soft silicon black ones to the metal plate ones. I suspect that the dual contact one will ultimately be the best choice

Why is the vagus nerve important?

There is mounting evidence that the vagus nerve is thickened or inflamed in long covid. This causes a low vagus nerve tone and prevents normal function.

  • The vagus nerve is extensively distributed throughout the body, serving multiple involuntary functions in different regions.
  • The vagus nerve provides sensation to the skin of the ear canal, parts of the external ear, as well as the internal surfaces of the lower throat (laryngopharynx) and the voice box (larynx).  It also provides sensation from the heart and abdominal organs.
  • Throat: Vagus nerve controls the muscles of the throat (pharynx), the flexible part at the back of the roof of the mouth (soft palate), and the larynx (including the vocal cords). These muscles are essential for activities such as swallowing, speech, and vocalization.
  •  Vagus nerve controls the muscles of the windpipe (trachea), air passages in the lungs (bronchi), and gastrointestinal tract. 
  • The vagus nerve controls and regulates the heart rhythm acting to decrease the heart rate.
  • In recent years, the understanding of the gut-brain axis, which involves bidirectional communication between the gut, microbiota, and brain, has significantly evolved. The vagus nerve, as a major component of the parasympathetic nervous system, plays a crucial role in this axis. It detects metabolites produced by the gut microbiota through its sensory fibers, relaying this information to the central nervous system. This integration within the central autonomic network leads to a response.
  • One notable pathway related to the vagus nerve is the cholinergic anti-inflammatory pathway, which can reduce inflammation and intestinal permeability, potentially influencing the gut microbiota composition.  Stress has been found to inhibit the vagus nerve, negatively impacting the gastrointestinal tract and the microbiota. These interactions contribute to the pathophysiology of gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), characterized by an imbalance in the gut microbial community.
  • Studies have shown that patients with IBD and IBS often have a low vagal tone, contributing to peripheral inflammation. The growing evidence of the bidirectional interactions between the gut microbiome and the brain supports a comprehensive model that considers the central nervous system, gastrointestinal system, and immune system, acknowledging the gut as an organ itself.


When the sympathetic nervous system (SNS) is kicked into overdrive, it’s out of balance with the parasympathetic and vagus nerve tone. This is most likely due to the initial cytokine storm that can occur during the acute COVID-19 infection.  At the same time the vagus nerve of the parasympathetic (PNS) is thickened and suppressed.

This part of our nervous system handles all of the automatic functions that we don’t even think about such as digestion of food, stimulating the acid to be released in your stomach, regulating the diameter of your lung airways, breathing rate, heart rate, pupil size, sweating, and much more.  It also directly and indirectly helps maintain body temperature, regulate your immune system, and control inflammation.  It has 2 components: the parasympathetic nervous system (PNS) and the sympathetic nervous system (SNS).  They work like a see-saw with each on either end.  Both are active at all times, but what actually happens depends on which one is in the driver’s seat or in control.

Your body is meant to have the PNS in the driver seat most of the time. PNS allows your body to heal and take care of maintenance. SNS is like a wrecking ball to our inside, or better yet, a bull in a China shop (although, I can’t think of any time I would want that).  It’s great for short term when needed but not 24/7. You are being exposed to epinephrine (adrenaline) and cortisol all day long.  You will not only be on edge and have anxiety, but you will also have a difficult time shutting down to go to sleep.

The parasympathetic (PNS) is responsible for body maintenance and building new tissue, healing, controlling inflammation, and your immune system. This is your fun and relax system.  Keep the heart rate slow, reduce how fast you take breaths.  Digest all that food you ate.  The vagus nerve leaves your brain and travels throughout the body following the carotid artery and then the aorta.  It helps regulate most of digestive organs including the gallbladder.  It also controls the pacemaker of the heart or the sinoatrial node.  It even helps to decrease blood glucose by getting it turned into glycogen and stored in your liver. 

The vagus nerve is part of our parasympathetic (PNS). It modulates the immune system and inflammation. When it’s not working like it should, we see autoimmune conditions sprout up. We see chronic inflammation of nerves, muscles, and joints.

Initially this happens because of direct damage from the covid-19 virus to the supporting cells of the nerves of your nose and tongue, however this tends to heal within a few weeks after recovering from the virus. The smell and taste problems may spontaneously resolve after a few weeks, or they may turn into a lasting effect. The abnormality is fueled by stress and illnesses because both increase sympathetic drive.

There have been many different treatments proposed, but the ones that appear to be most successful and reliably reproduced are the stellate ganglion block and the external ear vagus nerve stimulation.  There are many other treatments for other symptoms of long covid.