PVT, introduced by Stephen Porges in 1994, is a new understanding of our autonomic nervous system that offers an explanatory model for a wide range of illnesses and conditions that we previously had little understanding of why they occur and therefore how to treat them. These include conditions as varied as depression, fibromyalgia, obesity, PTSD, asthma, anxiety, digestive issues, and back pain. PVT also offers vagal tone as a potential diagnostic tool for measuring health in specific contexts.
You might be familiar with the old model for understanding our autonomic nervous system (ANS). It is binary: on or off, or rather either the sympathetic (fight-or-flight) part is engaged, or the parasympathetic (rest-and-digest) part is engaged. There is more nuance to this model, but essentially that is the view. What this view had no ability to explain were states like depression: clearly not an “active” state, like fight-or-flight, but also clearly not the happiness of rest-and-digest. Our ANS is never “offline,” so what state is it in when someone is depressed?
The Vagal Paradox
Back in 1992 Stephen Porges got a letter from a neonatologist in response to an article where Porges had written about “high cardiac vagal tone” as a measure of health. Vagal refers to the vagus nerve. The baby doctor noted to Porges that he had been taught that high vagal tone in infants indicated bradycardia (dramatic slowing of the heartbeat), a sign of distress that could quickly lead to death. This was the discovery of the Vagal Paradox: how on the one hand could high vagal tone indicate health and on the other be a sign of imminent death?
The vagus nerve was discovered and named by a Greek physician-philosopher-scientist, Galen, in the second century. What wasn’t discovered until the Vagal Paradox came to light, was that there is not one vagus nerve. There are two: the ventral vagus (VV) and the dorsal vagus (DV). The two nerves originate in the brainstem, but from different nuclei, and have different pathways in the body, and inervate different organs. According to Porges, “..the vagus nerve is not one nerve but a family of neural pathways” (Porges, p. 27)
The neonatologist was seeing high dorsal vagus (DV) tone that was mediating bradycardia and leading to the death of many babies. Porges was measuring respiratory sinus arrhythmia (RSA), which is the variation between each heartbeat, also called Heart Rate Variability (HRV), as a measure of health mediated by the ventral vagus (VV) nerve. This led Porges to inquire into our model of the autonomic nervous system and propose the Polyvagal Theory. He writes “[m]y motivation to solve the vagal paradox led to new conceptualizations of the autonomic nervous system and the formulation of the polyvagal theory.” (Porges, p. 6)
The PVT begins with the idea “that neurogenic bradycardia and RSA are mediated by separate branches of the vagus nerve.” (Porges, p.27). Many questions follow from this discovery. What else do these separate branches mediate? How are these branches related to the sympathetic (fight-or-flight) nervous system (SNS)? How do these three parts work together? Both ventral vagus and dorsal vagus are part of the parasympathetic nervous system. They do things other than stimulate action (the SNS does that). So, rather than two ANS states, Porges theorized that we (all mammals, actually) have three ANS states: Ventral Vagal (VV), Sympathetic (SNS), and Dorsal Vagal (DV).
The Polyvagal Theory
The understanding of what the SNS does didn’t change much from the old model. The first major difference is the nuanced understanding of the difference between VV and DV states. Porges introduced the term Social Engagement System to refer to when we feel safe and secure, we are open and happy and able to easily and productively engage with other people. This ability is mediated by the ventral vagal state. It is where we are alert and relaxed. This is where we want to be all of the time that we are not under a real threat.
To conceptualize the dorsal vagal state, remember the babies experiencing bradycardia, extreme slowing of the heart, their bodies were shutting down. Trauma researchers have described this state, often using the response of animals in the wild to paint the picture. Animals, when faced with mortal threat (the tiger is about to bite into the antelope) go limp, act dead, shutdown. This is not a conscious decision, but a nervous system response, the dorsal vagal response. This gave a new perspective to depression; perhaps depression is mediated by a dorsal vagal ANS response. Many illnesses and diseases, seen through the lens of PVT, seem quite different in terms of cause, and therefore treatment.
A few more pieces of the PVT are critical. The development of these parts of our ANS happened over time – evolutionary time. The dorsal vagal shutdown response is the oldest evolutionarily and sometimes described as reptilian. The SNS developed next and the ventral vagal was last and is exclusive to mammals. This hierarchy is not just in terms of history, but expresses itself in the current relationships between these parts of our ANS.
The Vagal Brake
The relationship between the parts of our ANS is most important in the concept of the vagal brake. The vagal brake refers to the action by the ventral vagus to slow down SNS or DV response and give the possibility of remaining in the VV state. Humans are best (happiest, healthiest, most productive) in the VV state and the body will seek to maintain VV state when possible (more on what it means to be in VV state below). However, life has challenges and obstacles which require the protective defenses mediated by the SNS and DV states. Sometimes we need to run to survive. Sometimes we need to greatly slow down our internal systems to focus energy on the minimum necessary for survival. However, once in the SNS state, it takes significant energy and time to regain VV state. It takes even more energy and time to recover from the DV state back to VV. Therefore, a healthy system tries to maintain VV state when possible and this is the role of the vagal brake.
I have read a lot of descriptions of our nervous system – from both the old and new models – that use analogies of survival in the wilderness to illustrate SNS fight-or-flight and DV shutdown. We don’t live like that anymore and I think those kind of analogies obscure modern day triggers and how we can get stuck in SNS or DV. Our beings are adaptive and we have these three to be able to adapt to our environments. We need all three and we need to be able to move between the states without getting stuck, with the possible exception of being “stuck” in ventral vagal. Our modern day triggers are increasingly created by ourselves and other people in social contexts: a friend glancing at their phone during lunch with you can trigger a slight dip towards SNS or DV; the ubiquitous pressure of cell phones present can keep us in SNS. Our nervous systems are constantly challenged to even know the VV state, as many people are chronically shifting just between SNS and DV, so much so that these states have become socially normalized.
The Sweet Spot: Ventral Vagal State
The ventral vagal state is when we are calm, our breathing is diaphragmatic, slow and steady. We are alert and happy. We are able to take in the faces and voices of other people. We are responsive in a socially engaging way. We are cooperative and collaborative. When we are like this, and the others around us are like this, we are happy, creative and productive.
Being around people in this state can put us in this state. This is called co-regulation and it starts with an infant’s relationship to its mother. Before words, there are faces and voices. When a baby cries, the baby is dysregulated – tired, hungry, wet, scared (missing mom). When the caregiver looks at, picks up, soothes by signing or talking, and addresses the baby’s physical needs, the baby becomes calm. The baby’s nervous system was regulated by the caregiver’s. This is the foundation of attachment theory. It is also something that happens between humans for their entire lives – one nervous system regulating another.
The ventral vagal state does not mean time when no problems arise. Problems and challenges continuously arise in life. In the ventral vagal state you will instinctually choose to meet those challenges with an open mind, awareness, collaboration, cooperation, calmness. If those strategies don’t work, that’s when the potential of shifting to SNS or DV occurs. Recovery from SNS or DV back to VV is critical. We are wired for it to happen naturally and with other people (co-regulation). For many people, this does not happen and they become stuck in SNS or DV, which, because their nervous system has made this choice, their perception and cognitive choices are limited, although they cannot perceive this. Their ANS is operating as if they are under threat and in danger, and that is the primary frame for every decision, thought, emotion and behavior.
Yoga is a remarkable practice for calming and regulating the nervous system. Although the ancient yogis did not have the terms that Porges has described in PVT, much of yoga can be viewed as seeking to regulate the nervous system and bring it into the ventral vagal state. Yoga is now described as integrative. It has always been, we just have these words for it now, and these words are important in bringing yoga therapy into service in broader healthcare contexts. Yoga treats the entire person and does not necessarily need to separate out, for example, obesity from depression, or acne from anger, or diarrhea from anxiety. It turns out, neither does the polyvagal theory. Dysfunction in the mind, body, and/or emotions, dysfunction in a human being can be seen through the PVT as dysregulation of the ANS. Shifting the frame of pathology opens the possibilities of new approaches to healing, even if some of those approaches are ancient.
Especially important for any kind of therapist is neuroception. Neuroception is a term coined by Porges in the development of PVT to name the process of the ANS scanning for safety and threat and then acting, by activating one of the three neural pathways, VV, SNS, or DV, as a response to the assessment of danger. “The autonomic nervous system is our personal surveillance system, always on guard, asking the question “Is this safe?” [It is] listening moment by moment to what is happening in and around our bodies and in the connections we have to others.” (Dana, p. 8) This is a kind of listening and responding and it happens below our conscious awareness. We have no control over it. Our ANS is in charge. “This is not the brain making cognitive choice. These are autonomic energies moving in patterns of protection. And with this new awareness, the door opens to compassion.” (Dana, p. 6)
Perception is managed through the senses and processed in the brain, cognitively, as in I see the red traffic light ahead of me, I perceive the light, its color and meaning to me as I drive toward it. Interoception is the sensing of one’s internal environment, as in when breathing diaphragmatically I sense my rib cage expanding and contracting with my breath. Proprioception is awareness of the position of the body, as in when I am swimming I am reaching my arm forward and then pulling it through the water underneath me. These three — perception, interoception, and proprioception — are cognitive. They involve sense organs for information, and that information is processed cognitively. This is not the case with neuroception, the “information processing” is done by the autonomic nervous system. “No matter how incongruous an action may look from the outside, from an autonomic perspective it is always an adaptive survival response. The autonomic nervous system doesn’t make a judgment about good and bad; it simply acts to manage risk and seek safety.” (Dana, p. 6)
The Autonomic Ladder as an Awareness Tool
Deb Dana, a clinical social worker, has created many tools based on her understanding of the PVT to help her clients understand their nervous system and heal. One of the most powerful of these tools she calls the Autonomic Ladder. It is an awareness tool. She teaches clients about each of the three ANS states: VV, SNS, and DV and then asks them to monitor where they are on the ladder throughout their day. Once clients have this in place she asks them to create two more tools: one that identifies triggers, for things that trigger one out of VV and into SNS or DV; “glimmers” – identification of things that one identifies with being in the VV state; and finally “resources,” where one lists internal and external resources available to move from SNS or DV back up the ladder to VV.
The ventral vagal state is the top of the ladder, it not only feels better to be in this state, but ventral vagal tone is highly correlated with overall health. How can you identify when you are in the VV state? You think about people important to you; you laugh and smile; you don’t feel rushed or pressured; you feel open to new ideas and creative; you are in nature; you are with people you care about or pets; you are listening to music; you feel relaxed yet aware. You are curious and have a sense of possibility and hopefulness. You feel grounded, in rhythm and connected. Dana notes that “[c]lients may be surprised by the unfamiliarity of this state.” (Dana, p. 27)
The middle rung on the ANS Ladder is SNS activation. Dana describes the SNS state as needing to do something NOW!, as feeling pressed for time, ignored, confused, or pushed to make a choice or take a side; as feeling responsible for too many people or things; as being around conflict. In SNS activation our negativity bias comes to the fore: neutral faces or situations seem dangerous to us in this state and we often misread social cues as negative. SNS brings strategies of confrontation or avoidance. SNS activation is “[n]ot limited to the act of physically engaging in violence, the fight response includes the full range of other behaviors aimed at changing things by force: verbal aggression in the form of sarcasm and abuse, passive aggression (opposing by not taking part), random aggression toward strangers, and wanton destruction of property. Similarly, flight is not only the act of running away — it includes actively avoiding people, situations, or places. It can be simply withdrawing from social situations by watching television or taking part in other solitary activities, possibly driven by anxiety or panic attacks.” (Rosenberg, p. 51) “Some of the daily living problems can be anxiety, panic attacks, anger, inability to focus or follow through, and distress in relationships. Health consequences can include heart disease; high blood pressure; high cholesterol; sleep problems; weight gain; memory impairment; headache; chronic neck, shoulder, and back tension; stomach problems; and an increased vulnerability to illness.” (Dana, p. 11)
The bottom rung on the Autonomic Ladder is DV activation. Dana describes DV as believing you are without options, you feel trapped, unimportant, criticized, as if you don’t matter, as if you don’t belong. (Dana, p. 34) Dorsal vagal activation is about immobilization, not only physically, but emotionally, cognitively, energetically, digestively. Physically you may feel foggy, too tired to think or act, lost, empty. The world may feel empty. “Some of the daily living problems can be dissociation, problems with memory, depression, isolation, and no energy for the tasks of daily living. Health consequences of this state can include chronic fatigue, fibromyalgia, stomach problems, low blood pressure, type 2 diabetes, and weight gain.” (Dana, pp 11-12).
Discernment is critical to healing and health. Having an understanding of PVT and a tool like the Autonomic Ladder to use to figure out where you and your clients are in the moment is an important way to move from theory to practice. The fact that many of us are dysregulated a significant amount of the time is evidenced by the overwhelming disease and complaints related to stress and/or depressive behaviors, both in body and mind. Dana noted that many of her clients discover that they are unfamiliar with feelings of being in the ventral vagal state, which indicated that they spend very little time there indeed. With the speed and constancy of modern life with cell phones and digital screens almost everywhere it seems normal to have noise, pressure, and multiple things happening at the same moment. These can be cues for SNS activation for some, or overwhelm and DV activation for others — and it has become normalized in Western society.
Western science and medicine has separated the mind from the body and although there is enormous evidence that one deeply affects the other, in practice, outside of integrative and complementary practices, we still have specialist for the mind and emotions and different specialists for the body. The PVT is another big piece of evidence in favor of integrative therapies. According to Rosenberg, “[i]n the conventional approach, however, doctors may be overlooking something.… The autonomic nervous system monitors and regulates the functioning of the visceral organs, and is a major contributing factor in determining our emotional state. However, doctors do not usually test its function” (Rosenberg, p.87).
Vagal tone can be measured by Heart Rate Variability (HRV) which is a measure of the difference from one beat to the next to the next (what is actually measured is called Respiratory Sinus Arrhythmia). If this sounds really small and difficult to conceptualize, it is. It is measured in milliseconds. You need a special monitor to detect and measure these subtle changes, although some body workers report being able to feel it when they take a client’s pulse. High vagal tone, which means there is a lot of difference between each beat, is correlated with multiple positive health measures. Rosenberg has come up with a simple test to see if the ventral vagus nerve is firing or not, at least pharyngeal branch function of the ventral vagus nerve, by checking if the arches next to the uvula and the uvula lift evenly (Rosenberg, p. 82-83). Since, we typically move in and out of the three states of the ANS throughout each day (and there are hybrid states, but that is beyond the scope of this article), a quick, easy to administer, low cost test for function is perhaps more useful than a precise but expensive measurement.
Yoga and Polyvagal Theory as Integrative Frameworks
“The Polyvagal Theory also presents another dimension to our understanding of the autonomic nervous system. The autonomic nervous system not only regulates the function of our inner organs; these three circuits also relate to our emotional states, which in turn drive our behavior.” (Rosenberg, p. 30) With the PVT we have a lens that sees our body and our emotional states and our behaviors in the same view. We have an integrative framework. Yoga provides an integrative framework as well. The two, polyvagal theory and yoga, as frameworks for understanding human health, disease, and suffering have profound parallels.
Specifically, there is a correlation between the ANS states — VV, SNS, and DV — and what is known in yoga as the gunas. The gunas, there are three, are the qualities of material nature. Yoga holds that the cause of suffering (including, but not limited to what in Western medicine we call disease or illness, mental and physical) is our relationship, reaction to, and misidentification with material nature, which is comprised of the gunas. A classic formulation of this misidentification is the difference between “I am angry” vs. “I am experiencing anger” or “anger is arising in me.” At its most fundamental yoga is about learning to discern this difference in the many ways it shows up in life.
The gunas are sattva, rajas and tamas. Sattva is known as illuminating, calmness, ease, clarity. Rajas is the energy of activation, striving, change. Tamas is heavy, dull, not moving. Just these short descriptions beg comparison with ventral vagal, sympathetic, and dorsal vagal states. Indeed, Sullivan et. al. posit “PVT can be conceptualized as a neurophysiological counterpart to the yogic concept of the gunas.” (Sullivan et. al., p.1). The gunas are how material nature shows up: depression and ice cream are heavy, dull; anger and cayenne pepper are active, strident; meditation and apples are calm, illuminating.
Sullivan et. al. posit, “[b]oth PVT and the gunas provide a perspective to understand underlying foundations from which physical, psychological and behavioral attributes emerge. PVT provides insight into how underlying neural platforms are activated in response to perceived threat or safety … Yoga suggests that physical, psychological and behavioral attributes emerge from and are influenced by the underlying interplay of the gunas.” (Sullivan, et. al., p. 8). Not only is this interesting from a historical perspective (yoga is at least 2000 years old, and as mentioned above the polyvagal theory was introduced in 1994), but it suggests a way to translate the essential framework and methods of yoga into terms that are understood and accepted by Western medical and scientific practitioners.
Further, both systems — PVT and the yoga gunas — provide a holistic reframing of health and disease that is not reductive; specific and knowable physical, psychological and behavioral attributes can emerge from a neural state or through the predominance of a guna and can be influenced and changed by shifting either the neural state or the balance of gunas in predictable ways. Many yoga therapists and teachers have known through experience the value of the comprehensive methodology of yoga that spans its eight limbs for healing which is predicated on the deep integration, or indeed, oneness of our being as opposed to the reductionism that has defined Western medical practices. “PVT provides a neurophysiological explanation of the methods and techniques embedded in yoga.” (Sullivan, et. al., p. 11). It is not an overstatement to say that polyvagal theory is revolutionary in terms of our understanding of our autonomic nervous system. It holds many other, perhaps more radical, possibilities, not the least of which is the understanding and acceptance of holistic healthcare and yoga therapy in the West.
● Escher Hands – public domain
● Autonomic ladder from Dana, p. 57
● Gunas CREDIT: https://beyogi.com/the-guna-greatness/
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