Vagus Nerve and Polyvagal Theory: How to Improve Your Vagal Tone for Better Mental Health

Your vagus nerve is one of the longest and most important nerves in your body. Yet, so many people are not aware of the role the vagus nerve plays in our daily lives. It’s critical for your nervous system health and mental health, but also for many areas of your physical health.

Poor vagus nerve function can lead to stress, anxiety, depression, inflammation, pain, and other symptoms. If any of these symptoms sound familiar to you, you may need to improve your vagus nerve function.

In this article, I want to explore the benefits of having a healthy vagus nerve. You will learn what the vagus nerve is, signs and causes of poor vagal tone, and how to improve your vagus nerve function for better health. Welcome to the world of polyvagal theory.



What Is Polyvagal Theory

Before getting into the nitty gritty of polyvagal theory, I want to talk about your autonomic nervous system (ANS). Traditionally, we understood the ANS as a system made up of two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Many doctors, psychologists, behaviorists, and therapists still use this two-branch model.

Here’s the gist of this two-branch thinking, involving a sympathetic response from the SNS, and a parasympathetic response from the PNS:

When encountering stress, your nervous system experiences a response which is essentially your body’s gas pedal. To respond to physical or emotional stress, your body generates energy. When I talk about stress, it doesn’t necessarily mean negative stressors. Sure, the SNS responds to negative stressors that involve danger and threat. But it also responds to positive stressors, such as excitement, physical activity, play, and healthy sexual action. It also responds to something called eustress, which is a goal-orientated or positive challenge in life that provides purpose or hope, such as a new job offer, a new and challenging workout program, or preparing for a presentation.

The relaxation response is a term coined by Benson, Beary, and Carol in 1974. It refers to a PNS deactivation process that restores peace and rest after stress, threat, or danger. This also helps to restore relaxation after a positive stress or eustress. You cannot be stressed and relaxed at the same time. But you also can’t be stressed all the time. We need balance – thus, the body needs to down-regulate and calm down.

However, this two-branch model of the SNS and PNS doesn’t take the vagus nerve into account. Discovering that the autonomic nervous system has three branches, not two, is thanks to the groundbreaking work of Dr. Stephen Porges. He realized that our body responds to various stressors depending on their importance, coordinated by the vagus nerve.

Mammals, including humans, have something we call neuroception, which refers to the ability to recognize threat, danger, and safety based on both external (exteroception) and internal (interoception) cues. So how does it work? Let’s look at these three branches:

Dorsal vagal complex (DVC):

The DVC is the most primitive branch of the PNS. This response leads to immobilization, or freezing, as a response to danger, overwhelm, shock, toxins, or other painful experiences. Essentially, your nervous system is saying, “we are not safe being here, so we will just leave this body”. Literally leaving the body is not possible, but freezing, not taking action, or even emotionally disassociating, is.

Sympathetic nervous system (SNS):

This is the well-known response that prompts mobilization, commonly known as fight or flight. We’re all familiar with this situation: when a bear is chasing you, you may have two choices; fight the bear (fight) or run away (flight). The fight response may involve intimidation, kicking, punching, or even shouting, and flight may involve literally running away or removing yourself from a stressful situation or conversation.

Ventral vagal complex (VVC):

This is related to the second branch of the PNS, and it’s responsible for social engagement. This provides a gentle break to the system, by turning to social interactions to regulate physiology, relax the body, restore safety, and promote health. It may involve crying, clinging, or other soothing mechanisms, finding resources, or tending friendships. When social engagement is not effective, the body may turn to fight or flight. When fight or flight is not an option or not effective, the freeze response is the next resort.

Now, all of this brings us to polyvagal theory and the vagus nerve. Your vagus nerve is your 10th cranial nerve or CN X. It is the longest nerve in your entire autonomic nervous system, and as a cranial nerve, it runs from your brain stem through your neck and chest to your abdomen (1).

Though we generally refer to the vagus nerve as one nerve, you actually have two branches of the nerve, one on the right and one on the left. These two nerves, together known as ‘the vagus nerve,’ connect your brain to your gut and other important organs (2).

Polyvagal refers to multiple vagi. Polyvagal theory talks about how the DVC and VVC depend on the vagus nerve. The response of the DVC and VVC depends on which parts of the vagus nerve are firing and whether in response to external or internal conditions.

The ventral vagus is located in the muscles of the face, neck, pharynx, larynx, and heart. It affects your facial expression, speech, and heart rate. This is critical for social engagement and creating safety through connection with others. When you are in danger, the middle ear starts paying attention to a sound frequency that may be related to danger, making it more difficult to understand certain frequencies of human voices, for example, during arguments.

The dorsal vagus connects the pharynx and larynx to your heart and gut thus it affects your gastrointestinal system and heart rate. In a state of danger, your gastrointestinal system may be affected, leading to gut-related symptoms. It may also trigger eating-related issues, such as stress eating or nausea and lack of appetite that also often accompanies stress. These happen when the ventral vagus is off.

Our goal is to support the ventral vagus to create balance, safety, and connection. It supports ‘freedom, friends, and forage’, which means that it helps to slow the heart rate down and support a social connection in a low tone DVC or an upregulated VVC state. Our goal is to achieve an appropriate response to the circumstances, heal the freeze response, learn how to find safety in our circumstances, and retrain the dysregulation of the autonomic nervous system (3, 4, 5, 6, 7, 9).


The Importance of Vagus Nerve Health

Vagal tone is activity of the vagus nerve. Vagus nerve health and good vagal tone are important for:

  • Decreasing blood pressure
  • Reducing heart rate
  • Lowering inflammation or pain
  • Managing stress and anxiety
  • Regulating mood
  • Transferring sensory information from the throat, lungs, and heart
  • Delivering information between the brain and the gut
  • Regulating swallowing
  • Regulating speech

stressed out woman

Symptoms of Poor Vagal Tone

Damage from injuries, infections, toxins, and mold to the vagus nerve may cause poor vagal tone, which may lead to symptoms due to nerve damage, including:

  • Abdominal pain
  • Nausea
  • Vomiting
  • Lowered stomach acid
  • Unusual heart rate (too high or too low?)
  • Unusual blood pressure
  • Loss of gag reflex
  • Loss of voice
  • Earache

You may develop poor vagal tone and vagus nerve-related symptoms even without damage to the vagus nerve. These symptoms may include:

  • High and chronic stress
  • Being in a constant fight-or-flight mode
  • Poor emotional regulation
  • Anxiety
  • Depression
  • Decreased attention span
  • Increased inflammation
  • Pain

woman using phone late at night

Causes of Poor Vagal Tone

So what can lead to many vagus nerve-related issues? Let’s look at the potential causes of poor vagal tone:

Early Childhood Traumatic Experiences

Traumatic experiences can influence our mental and physical well-being greatly. Traumatic experiences during early childhood may have even higher significance. This time is vital for your neurological and overall development. This is where you learn a sense of safety and comfort and safe social cues.

But if you grow up in an abusive or otherwise unsafe environment where you either don’t receive safe social cues or you receive mixed messages, you won’t be able to learn what safety and comfort feel like. Besides abuse and violence, other traumatic experiences, such as losing a parent, being in a serious accident, facing serious illness or hospitalization, living in deep poverty, and experiencing war, can also negatively affect your vagus nerve.

These traumatic experiences can lead to a chronic fight-or-flight or freeze state. If you score high on the Adverse Childhood Experiences (ACEs) test, you are more likely to have poor vagal tone, a sense of unsafety, and various physical or mental health issues as a result of your trauma (10, 11). Don’t worry, we will get to methods for healing your vagus nerve,  restoring healthy tone and shifting to more ventral vagus functioning.

Traumatic Experiences After Early Childhood

Your early childhood years are clearly critical for healthy development, mental health, and physical well-being. However, traumatic experiences later in childhood, during adolescence, and even during your adult years can impact your vagus nerve health and overall well-being.

Experiencing acute trauma, such as physical or sexual assault, domestic violence, serious illness, hospitalization, car accidents, poverty, or homelessness, may lead to post-traumatic stress disorder (PTSD) that is characterized by poor vagal tone. Research has shown that stimulating the vagus nerve may help to improve symptoms of PTSD (12, 13, 14, 15).

It may also be helpful if you’ve experienced repeated smaller traumas. An accident, losing a loved one, or being robbed are one-time significant traumatic experiences. We call these ‘big T traumas’. While some people experience several ‘big T traumas’ in life, some people never do.

However, we all experience so-called ‘small t traumas’. These are smaller events that many may chalk up as ‘part of life’, but can be traumatic on a personal level. Break-ups, being rejected by a friend, being made fun of, or losing a job are examples of this. Ongoing ‘small t traumas’ can create chronic stress, a chronic fight-or-flight state, and vagus nerve dysregulation (22).

Head Injuries

Head injuries, including concussions and traumatic brain injury (TBI), may cause an injury to the vagus nerve. Some of these injuries can have a long-lasting impact. Even if you had a minor head injury without a lasting physical impact, it might’ve been a traumatic experience causing poor vagal tone. Or there could be structural issues in the delicate head and neck region that need to be identified and addressed. Stimulating the vagus nerve may offer neuroprotective effects and support recovery from TBIs and head injuries (16).

Shallow Breathing

Let’s be honest. You may be unconsciously taking shallow or quick breaths throughout your day without being aware of it. Stress and anxiety can already lead to increased breathing and heart rate. Poor breathing mechanics send danger signals to the vagus nerve function leading to poor vagal tone and dorsal vagal responses. On the other hand, if you are taking conscious, slower, and deeper breaths, it can help you move out of a fight-or-flight state, shift you to ventral vagus and improve your vagus nerve function (17).

Chronic Stress and Not Enough Sleep

If you are experiencing chronic stress and not sleeping well or getting enough restful sleep, it can interrupt your sense of safety and compromise normal vagus nerve function. If you are constantly under stress, you may find yourself in a constant fight-or-flight state, characterized by increased cortisol levels, a rush of adrenaline, increased heart rate, shallow breathing, heightened senses, and difficulty sleeping.

This can wear you and  your nervous system down, interfere with synapse regulation, compromise vagus nerve function, hinder brain function, and negatively impact your mood. Chronic stress can increase poor sleep, but poor sleep can also increase stress, resulting in a vicious cycle of a fight-or-flight stressful state. Being in this state all the time may lead to mental health issues, cognitive issues, fatigue, and chronic health issues (18, 19, 20, 21, 22).

Blood Sugar Imbalances

Experiencing blood sugar imbalances from eating a diet high in refined sugar and processed carbs and low in micronutrients may compromise your vagus nerve function and overall brain health. Eating a quick high-carb snack may give you a sudden burst of energy, but it will be followed by a sugar crash, fatigue, brain fog, and other symptoms. Blood sugar imbalances may lead to symptoms resembling signs of poor vagal tone, including fatigue, anxiety, mood fluctuations, irritability, brain fog, and lightheadedness (23, 24, 25).

Environmental Toxins

Let’s face it, our modern world is full of environmental toxins, including air pollution, pesticides, conventional cleaning, personal hygiene, and beauty products, cigarette smoke, municipal tap water, moldy indoor spaces, plastics, and so on. Chronic exposure to environmental toxins may seriously impact your brain, neurological function, mental health, and overall wellness. High toxin load may disrupt your vagus nerve function, leading to fatigue, anxiety, depression, brain fog, and memory issues (26, 27).

Chronic Infections

Chronic infections, including the Epstein Barr Virus (EBV), Varicella zoster virus, chickenpox, Bartonella and Lyme disease, can all impact your brain and nervous system health. We know from research that chronic infections may play a role in chronic fatigue syndrome (CFS) and mast cell activation syndrome (MCAS) (28, 29, 30). We also know that these conditions may be characterized by poor vagal tone and its symptoms (31, 32). Chronic systemic infections may lead to chronic inflammation, pain, fatigue, brain fog, cognitive issues, anxiety, depression, and other mental or neurological health issues (33, 34, 35, 36).


woman meditating

How to Improve Your Vagal Tone and shift to Ventral Vagus

So how can you stimulate your vagus nerve to improve your vagal tone for better physical and mental health? This is what I recommend:

Meditation, Breathwork, and Gratitude

Meditation, breathwork, and gratitude are great ways to stimulate your vagus nerve, decrease stress, improve your nervous system and mental health, and simply enhance your overall well-being (43, 44, 45). I recommend that you start your day with a short meditation and breathwork practice followed by some gratitude journaling. Return to your breath throughout the day, especially when you feel stressed or anxious. Finish your day by recounting moments you are grateful for from your day.

Chanting or Singing

Impaired vagus nerve function can affect the muscles of your mouth and throat and, as a result, your speech and ingestion of food. Because your palatal muscles and vocal cords are connected to your vagus nerve, chanting, singling, humming, gargling, and talking are great options for stimulating your vagus nerve (37).


Laughing also helps to stimulate your vocal cords and palatal muscles, and as a result, your vagus nerve function. Laughter may also help to reduce stress, improve anxiety, create a feeling of safety, and boost your energy. Seek out social situations that bring you joy and laughter. Try laughter yoga. Watch a funny video or a comedy. Don’t be afraid to laugh at yourself (38).

Social Connections

The goal of polyvagal therapy is to recreate a sense of safety. What’s a better way to feel safe than being with supportive and loving people? Spend time with supportive friends and family. Seek out a supportive community. You may try volunteering, joining a book club, coloring group, or walking group, going to church or other spiritual gatherings, or taking a community class (39).

Movement and Exercise

Moving your body and exercising may help to release tension from your body and calm your nerves. I recommend that you move your body throughout the day and exercise at least five days a week. You may also benefit from body-based therapies, such as somatic experiencing or Stress, Tension, and Trauma Release (TRE) therapy, and movement or dance meditation practices, such as NIA, 5rhythms, and ecstatic dancing (40, 41). I also recommend reading Stanely Rosenberg’s Accessing to learn some specific exercises for vagus nerve function and health.

Bodywork and Acupuncture

Massage therapy, craniosacral therapy, chiropractic work,  and acupuncture are fantastic options for calming your nervous system and establishing balance in your body and mind. These alternative bodywork therapies may help to stimulate your vagus nerve, lower inflammation, decrease physical and/or emotional symptoms, and enhance your health (42, 43, 44, 45, 46)


You are what you eat. It sounds like a cliche, but your nutrition impacts your physical and emotional health. Following an anti-inflammatory, nutrient-dense, whole foods diet full of greens, vegetables, herbs, spices, sprouts, fruits, and organic animal protein may help to support your nervous system, thus your vagus nerve (47).


Besides good nutrition, you may also benefit from supplementation. Vitamin B12, other B vitamins, magnesium, zinc, vitamin D, and omega-3 fatty acids are all important for stress relief and neurological, brain, and mental health (48, 49, 50, 51, 52). I also like a product called Parasym Plus, which has been helpful to some patients. It helps to reduce inflammation and supports vagus nerve function. Since your vagus nerve, brain, and gut are closely connected, you may also benefit from taking a daily probiotic supplement (53).


Last but not least, you may also benefit from working with a counselor or therapist, especially if you have trauma, anxiety, or depression. I recommend seeking support from a therapist trained in polyvagal therapy. However, there are many other great modalities that can help with releasing trauma and calming the vagus nerve, including Eye Movement Desensitization and Reprocessing (EMDR), Brain Spotting, Trauma-focused cognitive behavioral therapy (TF-CBT), somatic therapies, psychodynamic therapy, and tapping (EFT or emotional freedom techniques) (54, 55, 56, 57, 58).  A modality that has been around since the 1970s in the realm of education called Brain Gym, has also been helping some of my patients improve their vagus nerve function.  Check out my colleague, Christina Boyd’s website for more information.

Vagus Nerve Stimulation Exercises and Devices

Luckily for those who struggle with low vagal tone, there are numerous targeted exercises and devices to help us!  I recommend picking up a copy of Stanley Rosenberg’s book, Accessing the Healing Power of the Vagus Nerve which has a detailed explanation and specific simple exercises.  I like a wearable device called Apollo Neuro that my patients and I have had good success with for sleep and anxiety.

There is also a device called the Rezzimax which was designed by a physical therapist to deliver vibrations to help especially with pain.  Some patients have done well with the Muse Headband or Brain Tap or the Hoolest.  My encouragement is to check out a couple and find one or 2 that you are jazzed to try. Ideally pick one that can be used passively like the Apollo Neuro and then one that requires more engagement, like a Biofeedback device such as Heartmath or the Muse or meditation.

Limbic System Retraining

Another critical component of our nervous system is the limbic system which is located in the central nervous system in the brain.  Most patients who have poor vagal tone, who are stuck in dorsal vagal in freeze or even in sympathetic overdrive, fight or flight, will also benefit from participating in Limbic System Retraining.  Stay tuned for a blog on this topic!

spring flowers

Next Steps

If you want to improve your health, I welcome you to check out the Spring Center which is now accepting new patients. Learn more about the practice  here.  If you are struggling with food issues, schedule a functional nutrition consultation with my nutritionist for nutrition support with Sarah hereVisit our store for products.

And if you enjoyed this blog and have discovered your favorite vagus nerve exercises or devices, I’d love to hear from you.  You can find me at @drkellymccann!

And stay tuned for more information to help you uncover the root cause of your health issues, improve your nutrition, repair your body, and regain your health naturally.