polyvagal theory

Many doctors are baffled by how to successfully treat chronic illnesses in their practice.  The conventional medical system typically offers only one strategy – treating symptoms with targeted drugs to (supposedly) relieve them – without ever getting at the root cause of the illness.  The Polyvagal Theory proposes a novel framework for chronic illness which can serve to improve those treatment efforts through an understanding of what caused the symptoms to occur in the first place.  Broadly, it explains how many different kinds of trauma (physical, emotional or toxic exposures) can leave the nervous system stuck in a way that disables certain critical body systems and leads to debilitating symptoms.

As someone who has experienced the devastating effects of this kind of dysautonomia firsthand, I’ve taken a deep dive into this topic and will describe it, as well as my experience with the treatment protocol, at the end.

Polyvagal Theory…Not-the-Disney-Kind of Frozen!

 As humans, like all vertebrate mammals, we are in possession of a complex nervous system which helps us to survive in and engage with the world.  Much of this crucial activity happens below the level of conscious awareness, as a part of the autonomic (think automatic) nervous system.  The autonomic nervous system is charged with many important survival functions like breathing, changes to heart rate and the process of digestion.  Without an optimally tuned autonomic nervous system, resilience is limited and life in the modern world becomes a challenge.

The autonomic nervous system consists of two different “arms” with differing functions based on the survival needs of the organism at any particular time.  These arms, the sympathetic and parasympathetic states, are commonly thought to be antagonistic, with the sympathetic arm allowing for “fight or flight” responses and the parasympathetic arm being charged with the “rest and digest” functions that support healing.  Any number of resources will propose that to properly heal from chronic illness, one must move from a constantly aroused sympathetic state to a calm, parasympathetic state.  And while this is true, it’s not the whole story.

Understanding why this is requires some understanding of the organization of the parasympathetic system.  The parasympathetic state is primarily regulated by a cranial nerve called the vagus nerve (CN X).   The vagus nerve is unique in the body in both structure and function.  It is the longest of the twelve paired cranial nerves, reaching from the brain to the abdomen and functions as a conduit of communication between the organs of the body and the brain. Branches of the vagus nerve serve the heart, lungs, larynx, stomach and ears.

The vagus nerve not only sends information out from the brain to the body, but perhaps more importantly, it also receives information from the body to be processed by the brain.  The vagus nerve regulates inflammation by sensing and responding to inflammation in the body.

Approximately 80% of the activity of the vagus nerve is processing this kind of bodily input below our conscious state of awareness.  Beyond inflammation, the vagus nerve also plays a role in memory formation.  When activated, heart rate and breathing slows, digestion is stimulated, and healing processes can occur.

But the parasympathetic state is not quite as simple as described above, leading Stephen Porges to further describe its complexity through his development of what he calls the Polyvagal Theory.  The vagus nerve can support states of relaxation, but it can also be overactive, leading to a state of functional immobility, or shutdown.

When the vagus nerve is overactive, a “freeze” response occurs, much like the proverbial deer in the headlights.  This is also a crucial survival response, the selection of which is completely out of conscious control.  When people are attacked and don’t fight back, it is a result of the vagus nerve activity supporting shutdown as the most appropriate strategy for survival.  Learning that this is a normal, adaptive response can often help trauma survivors let go of any lingering feelings of guilt or shame regarding their behavior during the traumatic incidents.   It was never under their control.

Mammals are meant to cycle freely in between these states as biologically appropriate for the conditions they find themselves in; however, it is possible to get “stuck” in a state that becomes disadvantageous.  Instead of the occasional flight from the pursuing raging tiger, modern stressors, like traffic or a difficult boss or partner, tend to be ongoing and unrelenting.

Porges finds that the development of chronic physical or mental illness is often a result of being unable to cycle out of the immobilization or “freeze” state, leading to a whole complex of the typical symptoms of chronic illness.  These symptoms are a result of dysautonomia, or dysregulation of the autonomic nervous system, and can include problems in any of the bodily areas the vagus nerve influences, which is to say nearly all of them.  Some of the more common symptoms include low heart rate, breathing problems like asthma, low blood pressure often leading to fainting, digestion problems like IBS, and sweating abnormally.

The Polyvagal Theory sets out to acknowledge these varying states of behavior based on different potential responses from the vagus nerve.  Therefore, there isn’t just one response from the vagus that is uniformly positive, but two different sets of vagal responses that are possible, depending on whether the perception of the environment is one of safety or one of threat.  These responses, according to the theory, are based on the evolutionary history of vertebrates and occur in an evolutionarily hierarchical manner.   Porges’ theory explains how the vagus nerve directly contributes to a coherent communication and connection system in the body.

Evolutionary Response 1:  Dorsal Vagal Complex or “Shutdown”

The most primitive response identified by the Polyvagal Theory is that of shutdown, immobilization or “freeze”.  This defensive response of the parasympathetic system, shared by reptiles, occurs when we are overwhelmed by a situation of danger.  It stems from a certain part of the vagus nerve, called the dorsal vagal complex.  The dorsal vagal fibers originate in a specific part of the brain called the dorsal motor nucleus and consist of unmyelinated fibers that mostly enervate organs below the diaphragm.  These organs include the stomach, spleen, liver, kidneys and small and large intestines.

Overactivation of the dorsal vagus complex leads to immobilization and produces troublesome symptoms as well, including sleep apnea, hoarseness, throat inflammation or pain, coughing, migraine, nausea or vomiting. Supposed “mental” health symptoms like fatigue, depression, or panic attacks can also be attributed to irregularities in vagus nerve functioning.  Cycling between feelings of overwhelm and shutdown is common to this state as well.

Evolutionary Response 2:  Sympathetic Activation

The next level of response, from the perspective of evolution, is a result of sympathetic nervous system activation.  This provokes the commonly experienced “fight of flight” response.  Because the sympathetic nervous system engages primarily to mobilize defense, heart and breath rates are increased, breathing becomes shallow, and blood flow is directed away from the digestive tract and towards the muscles in the arms and legs.

In this state, feeling anxious, panicky, or wired are common.   This is the most advantageous approach to acute stressors posing a life or death challenge.  However, in a constant state of low-grade stress, sympathetic activity increases chronically, ultimately leading to vagus nerve dysfunction.

People often arrive at their doctor in this highly dysfunctional combination of overactive dorsal vagus complex (shutdown) and burnout of the sympathetic response.  In this state, people will not be able to tolerate stressful situations well at all.  Symptoms of sound sensitivity, especially to loud noises, crowds and claustrophobia may predominate.  As a result, people tend to withdraw socially even more, setting up a vicious cycle.

Evolutionary Response 3:  Ventral Vagus Complex or “Tend and Befriend”

The most evolved and complex response to the environment again involves the vagus nerve, but a different part, originating from a totally different place in the brain.  Unlike the dorsal vagal complex, the ventral vagal complex originates in the brainstem and is comprised of a network of myelinated fibers which can transmit information quickly.  These neural fibers are responsible for our heart rate and breathing as well as social communication and engagement. This is the part of the vagus nerve that tells us it is safe to “tend and befriend” other members of our species.

Mammals owe their survival throughout the ages to their ability to communicate and cooperate with others.  The social engagement system, by way of the ventral vagal complex, orchestrates activities like hearing, the movement of small facial muscles between the eyes and the mouth and vocalizations.  A melodic voice, lacking in the deeper registers that often signal danger, triggers feelings of safety to the listener.  A smile that reaches the eyes does the same.

These activities are crucial cues of safety between members of a species and indicate when it is safe to approach or when it would be better to stay away.  As a result, activities like play (aggression without fear) or intimacy (immobilization without fear) between members of a species, becomes possible.

All of this crucial cooperation happens as a result of the more evolved vagal system inhibiting the older, less evolved systems.  When the newer system isn’t available, the autonomic system goes into a state of defense, and physical health declines.  Symptoms of heart disease, gut problems, fibromyalgia, and others can be a result of excessive defensive physiology.

For example, the natural heartrate set by the pacemaker node of the heart would naturally lead to a heartbeat of approximately 110 beats per minute.  The ventral vagal complex applies a vagal “brake” to those cells and slows the heart rate down to the more typical 60-80 beats per minute at rest.  When it is time to appropriately mobilize, it isn’t necessary to always activate the entire sympathetic system; instead the vagal brake can be released, and the heart rate can increase slightly to allow for the increased activity.  Without this type of fine regulation, the autonomic nervous system cannot work smoothly, and ill health is the result.


Porges has coined the term “neuroception” to describe this awareness of the nervous system that happens outside of conscious control.  Neuroception helps to explain why we feel uncomfortable in certain settings or around certain people.  It may be that they, consciously or not, are violating our neural expectancy of reciprocity in social engagement, leading us to more defensive behaviors in response.  Something as silly sounding as “resting b*tch face”, characterized by a flat, mean expression lacking a natural smile, can be a sign of an out-of-tune social engagement system rather than any true indication of malevolent personality.

However, humans tend to treat other people as if all behavior is intentional, rather than a result of the physiological state they are in at any given moment.  Hypervigilance and hyperactivity, for example, can alternatively be viewed through a different lens where the vulnerability of stillness leads to inappropriate mobilization.  In other words, without appropriate activity of the vagus nerve, stillness feels more like becoming the proverbial sitting duck and movement helps to relieve this subconscious anxiety.

Understanding neuroception, then, provides a rationale grounded in neurophysiology for giving people the benefit of the doubt, understanding that they may be acting in culturally inappropriate ways as a result of being in a state of defense rather than as a willful act of aggression.

Polyvagal Theory posits that the objective facts surrounding a traumatic event matter less than the individual’s response to that event or threat. How others might respond in the same situation is of little importance, which may help to explain why some people experience more symptoms of post-traumatic stress than others after the same event.

Safety is not simply about removing a threat, it is about promoting other environmental cues that allow our bodies to give up our defenses and return to a more highly evolved level of cooperative function.  The people who can return to the more highly evolved systems of social engagement after a traumatic event are less likely to remain stuck in the defensive modes that disrupt physical homeostasis.

Recognizing Defensive States

Above all, feelings are signals from the body, providing important regulatory information.  Awareness of these feelings is the first step towards helping the body move out of defensive states, when inappropriately stuck.  Instinctive defensive reactions can be offset by providing intentional, learned cues of safety and trust from the environment.   This can happen in the presence of trusted loved ones, a therapist, or even our beloved pets!

Learning to recognize and consciously navigate out of defensive physiological states can go a long way towards improving health, especially chronic health conditions.  Activation of the ventral vagal complex can bring a person out of both sympathetic overdrive and parasympathetic under-arousal states.  These beneficial activities include breathing exercises focused on the long, steady exhalation, common to pranayama or other yogic practices.

Playing wind instruments also activates those circuits.  Singing, chanting or humming can also help to tone the vagus nerve.  Doing these things in a group of trusted people may be especially helpful in helping to co-regulate one another’s physiological state.  Activating the dive reflex by immersing the face in cold water is another strategy while massage, craniosacral therapy and acupuncture may also help to tone the ventral vagal pathways that promote a sense of safety and well-being.

Heart Rate Variability

Because the vagus nerve has an impact on the regulation and rhythm of the heartbeat, measuring a parameter called heart rate variability (HRV) may provide some insight into the autonomic physiology as well.  The heart does not typically beat in a perfectly steady manner with the exact same interval between beats.  Instead, there is a minute variation between one beat to the next that can be measured with a variety of devices designed for that purpose.

Typically, the higher the HRV, the better, indicating a more flexible state of autonomic regulation.  However, it is not quite that simple, as there are other factors that also influence HRV, like the baroreflex or hormones, and there are times when a lower HRV may be most appropriate, like when appropriately engaging mobilization for either play or defense.  However, with some common sense and context, HRV can provide some useful insights into the state of the autonomic nervous system.

The Safe & Sound Protocol

Porges has further developed an interventional listening system based on the Polyvagal Theory called the Safe & Sound protocol (SSP).  This research-based therapy consisting of a five-day auditory protocol is designed to reduce stress and sensitivity to sound while promoting social engagement and resilience.

The protocol stems from knowledge of the workings of the middle ear where structures help to extract human voice from background sound.  These low-frequency background noises can signal a state of danger, where it becomes physically difficult to hear human voices.  People who have difficulty hearing in crowded restaurants or other public places, may find their auditory nerve shows no deficits in testing as their hearing “loss” is a really a result of a loss of vagal tone instead.

The music of the SSP protocol has been digitally processed to train the muscles of the middle ears back to the frequencies most common to human speech, while eliminating the lower frequencies signaling danger.  Listening to this specially processed music dampens defensive responses and improves the functioning of the cranial nerves involved in promoting social behavior.

Through this type of brain stimulation, neurons in the vagal and sensory networks become more active and recruit even more neurons, thus developing new patterns and habits as a result of neuroplasticity. The user re-learns to focus on human speech, enabling self-soothing and proper autonomic regulation.

Through conscious effort, awareness may be brought to the unconscious process of neuroception.  In that state, one can begin to consciously seek out cues of safety in the environment in order to help re-tune those autonomic processes.  As a result, the user is able to engage more fully in other therapeutic endeavors.  This leads to more successful therapeutic outcomes overall including increased attention and the ability to better regulate physiological state.

If the Polyvagal perspective is correct, the autonomic nervous system becomes the basis for our interpretation of literally all lived experiences.  It explains how we choose to engage with the world, whether we look for appropriate social interaction opportunities, like play or intimacy with trusted partners, or attempt to protect ourselves through isolation and fearful immobility.

Dysfunctional attempts to regulate state explain not only social engagement behaviors but also addiction behaviors including drug use or disordered eating.  While past experiences might teach us to depend on a more ancient defensive response, the Polyvagal Theory provides a roadmap for re-tuning the foundational autonomic nervous system back to a more healthy, resilient state.

 My Experience with the SSP

My first question when learning about any new program or theory is always, “But is there anything that can be done to fix this?”.   Theoretical knowledge is useful but is limited in impact without concrete strategies to implement it in real life.  Luckily, Stephen Porges has developed the Safe and Sound Protocol (SSP), based on the Polyvagal Theory, to reduce stress and calm the physiological state through activation of the social engagement system.

The five-day listening protocol aims to produce a grounded state promoting signals of safety, calm, and social connection.  This opens the door to further therapeutic interventions, which can become much more effective once a person is in a more receptive physiological state.

The SSP is distributed through Integrated Listening Systems, who holds a license to use the patent, and is implemented by many different types of mental health practitioners.  I chose to work with a group of occupational therapists called Brain Harmony.  Based in Florida, but licensed nationwide, Carol Garner-Houston and her team routinely work with patients of all ages all over the US using phone and Skype appointments.

After a free initial call, I filled out a history detailing the specifics of my illness and prior accidents involving head trauma specifically.  Following that was the Measure of Foundational Abilities, a functional assessment checklist, designed to assess deficits in areas such as balance and motor control, sensory experience, language, organization and attention, sleep, and social engagement.  After digitally signing all the rental paperwork for the system, it was time to schedule my kickoff call.

Everything happened very quickly once the ball started rolling.  There was just about a week between my first inquiry to Brain Harmony and the kickoff call.  On that call, Carol explained more about the program and walked me through the setup of the equipment so that I was ready to get started.  All of the initial and follow-up training is included in the monthly equipment rental fee of $395.

The SSP is very simple; the required equipment is simply a box containing a pair of over-the-ear headphones and a small mp3 player programmed with the specially processed musical tracks.  The tracks come in two flavors – one for adults and one for children — organized into playlists, one for each day of the protocol.  Each day I listened for approximately one hour, however, the program can be broken down and taken even more slowly for those who are more sensitive to sound.

According to the Polyvagal Theory, when in a state of shutdown or freeze, the middle ear muscles begin to focus on the lower pitched sounds signaling danger.  Over time, this changes the function of those muscles inside the ear so that they have difficulty switching over to focus on the frequencies involved in human speech.  This protocol systematically exercises those muscles so that it is easier to “hear” human speech and reap the benefits associated with connection with others.

The adult tracks are mostly female voices (female voices are typically perceived as less threatening) without any booming low frequencies that would typically signal danger.  Artists from the adult list include many of my favorites like Norah Jones, Whitney Houston, Allison Krauss, and Sarah McLachlan.  A few men, like James Taylor and Michael Jackson, do make the cut too!

The tracks chosen are all positive in tone, chosen to signify safety through a positive experience of love and closeness.  Examples include songs like I Will Survive, You’ve Got a Friend, Baby Love, and many more.  The kids get songs appropriate for their age, mostly Sesame Street type music or nursery rhymes.

Even though the songs are familiar, the music doesn’t sound “normal”.  It sounds a bit tinny and distorted to reflect the intentional loss of certain frequencies.  It fades in and out, from one ear to the other, in specific ways designed to exercise the muscles of the middle ear.   It’s not at all unpleasant, even though it is definitely lacking in the richness of the original tracks.

I was told that some people experience a sense of flushing or warmth in the face, signaling activation of the vagus nerve.  While I didn’t notice much acutely, I did notice an emotional response to the music that was at times quite strong.  Carol explained to me that was also a normal response to the program.

During the listening experience, the hardest part for me was not falling asleep during the session.  It’s important to stay awake to let the ear muscles work properly.  Many people do quiet activities, such as reading a book, but avoid anything too stressful or aerobic in nature.  My natural inclination was to look at my phone, but electronics are not ideal as they have a built-in reward process that may interfere with the training.  Further, it’s too easy to let upsetting posts on Facebook or other social media sites trap oneself into “danger” settings, which would, of course, be counterproductive.  Quiet, not-too-demanding activities, done in the presence of a trusted friend or pet are best.

After I completed the five-day session, I had a scheduled follow-up call with Carol where we discussed my experience listening to the tracks.  Because I am an adult, with more deeply entrenched patterns, she explained to me that it may take more than one pass through the system.  We decided that after a five-day break, I would repeat the listening sessions a second time.  Many people do end up repeating the sessions, but typically not more than four or five times.

The second time through I felt much more relaxed about the whole process.  I knew what to expect from it all, which contributed to a more overall sense of safety.  I also made a more conscious effort to not look at my phone at all during the sessions, reading a paper book or magazine instead.  Once or twice, I worked on the jigsaw puzzle with my mom during the session as well.

Carol also emphasized the need for follow-up work to cement the opening of the social engagement system.  The SSP can open the door and make someone more receptive to social connections, but this needs to be reinforced in the environment as often as possible.  Some people take the system and listen in a quiet public place where it’s possible to make eye contact with people.  Mostly I just made eyes at my dogs in the privacy of my own home, because being out in public still has a tendency to put me on edge.

After the second round, Carol heard my report and determined that progress had been made and that it was time to move on to the Focus part of my personalized training program.  The Focus protocol is another Porges’ invention that involves listening, but it is not a part of the SSP.  Many people do combine them for maximum benefit; however, the Focus part of the experience is typically up to ten months, unlike the relatively quick SSP.

I have definitely noticed that eye contact with others feels less threatening after doing the protocol.  I don’t think I consciously knew that I avoided looking at people, though I had noticed that I had to make an effort to do so as a part of “normal” social behavior.  But I’ve even noticed that I look more deeply into the dogs’ eyes, especially during training activities, and that seems to have made a big difference in their responsivity to me as well.

Bottom line?  The SSP won’t change your life in five days.  That’s just not how the brain or neuroplasticity works.  Repetition over time is always a part of learning new patterns of behavior. But I do believe that it can lay that important foundation and prepare the nervous system for positive change moving forward.  Carol describes the process as Inch Stones, slow changes that add up to big results over time.

Overall, my experience with the SSP has been a positive one.  Working with Carol and the Brain Harmony team is both easy and convenient.  Going in, I didn’t know exactly what to expect in terms of results.  After finishing the SSP part of the protocol, I understand that it is the foundation on which I can continue to consciously build upon, both with the Focus training and with other types of ventral vagal stimulation, such as singing and chanting and other breathwork.  Further, it has encouraged me to look for situations where safe social engagement is possible to continue building upon the benefits of the SSP.


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Porges, S. W. (2017). The pocket guide to the polyvagal theory: the transformative power of feeling safe. New York: W.W. Norton and Company.

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