Ongoing research suggests that a better understanding of the vagus nerve could revolutionize how we treat various physical and mental health conditions, including epilepsy, obesity, inflammatory disorders, depression, and anxiety (Wade, 2023; Neuhuber & Berthoud, 2022).
According to the polyvagal theory, lowering “autonomic states that support threat reactions” (Porges, 2022, p. 2) and boosting ones that encourage feelings of safety can benefit our psychological wellbeing, potentially helping individuals who have experienced trauma.
This article introduces the polyvagal theory and some of its challenges and offers exercises and resources to support its use by mental health practitioners with their clients.
It is widely accepted that there are two distinct and continuously active divisions in our autonomic nervous system (Bridges & Porges, 2015; Tindle & Tadi, 2022).
The parasympathetic system is associated with us being calm. When active, our heart rate is down, our breathing is regular, and our digestive system feels comfortable.
On the other hand, when our sympathetic–adrenal system is on high alert, our heart rate is elevated, adrenaline is secreted, and ingestion and digestion are difficult. During this time, our focus moves to the safety of our bodies (Bridges & Porges, 2015).
According to polyvagal theory, the two systems are in constant dialogue. When everything runs normally, there is a bidirectional flow of energy and information, and the two work in harmony (Bridges & Porges, 2015).
However, when there is a problem and we feel threatened, that flow changes, and we engage our primary survival mechanism — fight or flight — and are primed for action (Bridges & Porges, 2015).
It’s not always a bad thing. Whether our ancestors were escaping a lion, or we are jumping out of the way of a taxi, we need heightened awareness, focus, and instantaneous action to maintain our safety.
The theory holds that even when a threat has passed, our bodies can remain in a state of perceived danger, our defenses engaged, and we experience prolonged stress and anxiety. We can be left with trauma present in the body in the same way it inhabits our memories (National Institute for the Clinical Application of Behavioral Medicine, 2022).
As a result, treating trauma may be less about managing the upsetting experience and more about treating the resulting physiological response (National Institute for the Clinical Application of Behavioral Medicine, 2022).
Bridge and Porges (2015) have also suggested that several of the markers associated with autism, such as reduced social engagement, poor facial affect, and auditory hypersensitivities, may also result from disruption to the autonomic state.
Polyvagal theory explained simply - Sukie Baxter
For a clear and insightful introduction to the theory, check out this video from Sukie Baxter.
The polyvagal theory: the new science of safety and trauma
Seth Porges’s video introduces the new science of safety and trauma, born out of the ongoing research into the functioning of the vagus nerve.
Stephen Porges and the Origin of the Theory
“The vagus nerve is a bundle of neurons connecting the brain to many of the major organs, with nerves running both from the organ to the brain and vice versa” (Wilson, 2011, para. 2). Among other things, it helps regulate our heart rate, breathing, and appetite.
The polyvagal theory was developed by Stephen Porges, founding director of the Traumatic Stress Research Consortium at Indiana University, in the early 1990s. His research into the vagus nerve suggested a link between our evolved autonomic nervous system and our social behavior, behavioral problems, and psychiatric disorders (Kseib, 2022; Polyvagal Institute, n.d.).
The theory’s proponents believe it offers a “mind–brain lens” to examine, explore, and resolve psychological problems (Simpkins & Simpkins, 2013, p. 236).
According to Porges (1995), the autonomic nervous system has three primary states:
Ventral vagal state
A calm and connected state that supports social engagement, emotional regulation, and effective problem-solving
Includes the “fight or flight” response associated with fear and anxiety that helps individuals respond (though not always appropriately) to perceived threats
Dorsal vagal state
Connected with immobilization and shutdown responses, potentially leading to feelings of dissociation, numbness, and disconnection
Porges (1995) suggests that trauma leads to shifts in our autonomic state.
When in a state of threat, our nervous system fails to regulate bodily organs or manage social relationships successfully, and our priorities change. We move away from growth, restoration, health, and forming connections with others to survival and the here and now (Kseib, 2022; Porges, 2022).
The polyvagal perspective argues that we should think of trauma in terms of retuning the nervous system. To heal ourselves or our client, we should give the “nervous system the cues of safety so that it re-tunes itself to being more homeostatic,” says Porges (as cited in Kseib, 2022, para. 7).
As a result, when we start to listen to our nervous system, we lose the feelings of shame and hopelessness associated with believing we are at fault, freeing us to navigate through complex or challenging environments (Kseib, 2022).
Clinicians often measure vagal (relating to the vagus nerve) tone as an indication of levels of vagal activity. While impossible to observe directly, it can be estimated through heart rate variability — the time fluctuations between heartbeats (Marmerstein et al., 2021).
The window of tolerance
The window of tolerance is not a term central to the polyvagal theory and was not developed by Porges, yet it broadens our perspective on the activation and regulation of the nervous system (Siegel, 1999).
According to Siegel (1999), it is a physiological and emotional regulation state where individuals can effectively cope with stressors and engage in social interactions.
As a result, understanding, promoting, and expanding this window may be considered central to supporting wellbeing and resilience (Siegel, 1999).
Our polyvagal world with Stephen and Seth Porges
In this video, Stephen Porges introduces his son Seth and explores the impact of trauma on the human body in an engaging interview for The Science of Psychotherapy.
Criticisms Against the Theory
Despite gaining widespread recognition and acceptance in the field of psychology and therapy, the polyvagal theory has been met with criticism.
Lack of empirical evidence
Critics argue that while the theory is compelling, it lacks robust empirical evidence to support its claims. Therefore, more rigorous research has been called for to validate its predictions further (Cacioppo et al., 2016).
Simplistic view of the nervous system
The polyvagal theory may oversimplify the complexities of the autonomic nervous system. As a result, some experts suggest a more nuanced and multifaceted view to fully understand the nervous system’s functioning (Porges, 2018).
Overemphasis on vagal tone
The theory heavily emphasizes vagal tone as a central indicator of the autonomic nervous system’s interplay with other physiological systems, such as the endocrine system (Beauchaine, 2015).
While these and other criticisms exist, the polyvagal theory has also received considerable support and is integrated into various therapeutic approaches (Dana & Porges, 2018).
Prescription drugs are a common treatment for trauma, with individuals often experiencing improvements in their overall coping and wellbeing. Yet research shows that pharmaceuticals can have their pitfalls, including side effects and subsequent resurfacing of symptoms when treatment ends (Althaver, 2020).
Psychotherapy has also been effective for treating clients who have experienced trauma, with therapists adopting various approaches, including the following (Althaver, 2020):
Cognitive-Behavioral Therapy (CBT)
Changing thoughts and beliefs about the trauma to transform emotions and behaviors
Eye-movement desensitization and reprocessing (EMDR)
Stabilizing thought processes by using dual attention to strengthen connections between brain hemispheres and disrupting the traumatic memory network (American Psychological Association, n.d.)
Studies have shown both CBT and EMDR to be effective at healing trauma in clients (Van der Kolk, 2015; Wheeler, 2007). Other treatments include virtual reality, yoga therapy, and mindfulness training (Althaver, 2020).
Training in polyvagal theory – 5 Courses
The following trainings provide an opportunity to form a deeper understanding of polyvagal theory and how to use it with clients.
The Polyvagal Institute
Experts in the field, including Stephen Porges and Deb Dana, teach the following courses:
Understand the role of the brain and the nervous system in responding to and treating trauma. The course recognizes the importance of the polyvagal perspective in providing more targeted treatments.
The goal of therapeutic interventions informed by polyvagal theory is to help individuals expand their window of tolerance. They promote self-awareness and self-regulation techniques that can return the autonomic nervous system to a regulated state (Porges, 2018).
To do so, therapists often use techniques such as mindfulness, deep breathing, and various forms of somatic (or bodily) therapy with clients (Fallis, 2017).
Deep and slow breathing
Deep, slow breathing has been shown to stimulate the vagus nerve, reduce anxiety, and boost the parasympathetic system (Fallis, 2017).
Try several of our free breathing and grounding exercises.
Anchor Breathing Exercise The exercises include seven steps based on breathing deeply and calmly, while visualizing an anchor to represent staying where you want to be.
Immersion in cold water, whether turning the temperature down for the final 30 seconds of a shower or purposeful dips in a frigid body of water, can calm the sympathetic fight-or-flight response, reduce inflammation in the body, and help with mental health conditions such as anxiety and depression (Barnes, 2011; Harper, 2022).
3 Books About the Polyvagal Theory
Polyvagal theory continues to fascinate researchers, academics, and mental health practitioners. It offers an alternative or addition to many more-established ways of thinking about trauma and mental wellness.
The following books are three of our favorites on the theory.
1. The Polyvagal Theory in Therapy: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-regulation – Stephen W. Porges
Stephen Porges combines decades of research into one vital text and explores the role of the autonomic nervous system in mediating social engagement, intimacy, and trust.
It is an essential book both for those new to the theory and existing researchers wishing to dig deep into the findings underpinning the approach.
Whether we view polyvagal theory as revolutionary or controversial, it can potentially transform how we think about physical and mental wellness.
The approach, based on a deep recognition of the balance between the sympathetic and parasympathetic divisions within the autonomic nervous system, offers new insights into treating depression, anxiety, and trauma (Wade, 2023; Neuhuber & Berthoud, 2022).
When everything is performing well, the two have an ongoing and bidirectional flow of energy and information. Still, it can be disrupted when we experience threat or trauma.
Psychological and physiological healing occurs when we retune our nervous system to become more balanced or homeostatic (Porges, 1995).
For you as a mental health practitioner, this can mean identifying and using treatments and interventions that encourage your clients to consider and listen to their vagal tone, supporting the regulation of their vagus nerve (Marmerstein et al., 2021; Siegel, 1999).
Such activities and exercises are readily available and can easily be incorporated into existing treatment programs and include mindfulness, deep breathing, and somatic techniques such as self-touch and vocalization.
While the polyvagal theory has its critics, it offers a safe and potentially transformative approach to wellbeing that supports balance within our own or our clients’ nervous systems.
Stephen Porges (1995) developed the polyvagal theory in the early 1990s based on his research in neurobiology and his efforts to understand the interplay between the autonomic nervous system, social behavior, and the body’s responses to stress and trauma.
What is the vagus nerve?
The vagus nerve continues to fascinate physiologists and psychologists as the sensory superhighway connecting our brain to many vital organs and regulating our bodies’ functioning (Wade, 2023).
Why is the polyvagal theory controversial?
The polyvagal theory remains controversial due to concerns regarding its scientific validity and emphasis on the importance of vagal states for our physical and psychological wellbeing. Some critics suggest that while the theory offers a fascinating narrative and insights, it is not backed by robust empirical evidence (Cacioppo et al., 2016; Porges, 2018; Beauchaine, 2015).
What is vagal tone?
Vagal tone is believed to indicate the overall levels of vagal activity. While it is unclear how to measure it directly, it can be estimated through heart rate variability — the fluctuations in the time between heartbeats (Marmerstein et al., 2021).
Althaver, M. (2020). Treating trauma: The occupational therapy perspective [Senior honors project, Bridgewater College]. https://digitalcommons.bridgewater.edu/honors_projects/14/.
American Psychological Association. (n.d.). Eye movement desensitization and reprocessing (EMDR) therapy. Retrieved September 28, 2023, from https://www.apa.org/ptsd-guideline/treatments/eye-movement-reprocessing.
Barnes, V. (2011). Using mindfulness and the dive reflex as techniques from Polyvagal Theory to regulate approach motivation (Order No. U574365) [Doctoral dissertation, University of Exeter]. ProQuest Dissertations & Theses Global. https://www.proquest.com/dissertations-theses/using-mindfulness-dive-reflex-as-techniques/docview/1124007234/se-2.
Beauchaine, T. P. (2015). Future directions in emotion dysregulation and youth psychopathology. Journal of Clinical Child and Adolescent Psychology, 44(5), 875–896.
Bridges, H., & Porges, S. W. (2015). Reframe your thinking around autism: How the polyvagal theory and brain plasticity help us make sense of autism. Jessica Kingsley.
Cacioppo, J. T., Tassinary, L. G., & Berntson, G. G. (Eds.). (2016). Handbook of psychophysiology (4th ed.). Cambridge University Press.
Dana, D., & Porges, S. W. (2018). The polyvagal theory in therapy: Engaging the rhythm of regulation. W.W. Norton & Company.
Fallis, J. (2017). How to stimulate your vagus nerve for better mental health. Retrieved September 28, 2023, from https://sass.uottawa.ca/sites/sass.uottawa.ca/files/how_to_stimulate_your_vagus_nerve_for_better_mental_health_1.pdf.
Harper, M. (2022). Chill: The cold water swim cure. Chronicle Prism.
Kseib, K. (2022, November 23). ‘Our nervous system is always trying to figure out a way for us to survive, to be safe.’ The British Psychological Society. Retrieved September 28, 2023, from https://www.bps.org.uk/psychologist/our-nervous-system-always-trying-figure-out-way-us-survive-be-safe.
Marmerstein, J. T., McCallum, G. A., & Durand, D. M. (2021). Direct measurement of vagal tone in rats does not show correlation to HRV. Scientific Reports, 11(1).
Neuhuber, W. L., & Berthoud, H. (2022). Functional anatomy of the vagus system: How does the polyvagal theory comply? Biological Psychology, 174, 108425–108425.
National Institute for the Clinical Application of Behavioral Medicine. (2022). Polyvagal theory and how trauma impacts the body. Retrieved September 28, 2023, from https://www.nicabm.com/trauma-polyvagal-theory-and-how-trauma-impacts-the-body/.
Polyvagal Institute. (n.d.). What is the polyvagal theory? Retrieved September 28, 2023, from https://www.polyvagalinstitute.org/whatispolyvagaltheory.
Porges, S. W. (1995). Orienting in a defensive world: Mammalian modifications of our evolutionary heritage. A Polyvagal theory. Psychophysiology, 32(4), 301–318.
Porges, S. W. (2018). The pocket guide to the polyvagal theory: The transformative power of feeling safe. W. W. Norton & Company.
Porges, S. W. (2022). Polyvagal theory: A science of safety. Frontiers in Integrative Neuroscience, 16.
Siegel, D. J. (1999). The developing mind: Toward a neurobiology of interpersonal experience. Guilford Press.
Simpkins, C. A., & Simpkins, A. M. (2013). Neuroscience for clinicians. Springer.
Tindle, J., & Tadi, P. (2022). Neuroanatomy, parasympathetic nervous system. StatPearls. StatPearls. Retrieved September 28, 2023, from https://www.ncbi.nlm.nih.gov/books/NBK553141/.
Van der Kolk, B. A. (2015). The body keeps the score. Penguin.
Wade, G. (2023). Unravelling the secrets of the vagus nerve will revolutionise medicine. New Scientist. Retrieved September 28, 2023, from https://www.newscientist.com/article/mg25934530-500-unravelling-the-secrets-of-the-vagus-nerve-will-revolutionise-medicine/.
Wheeler, K. (2007). Psychotherapeutic strategies for healing trauma. Perspectives in Psychiatric Care, 43(3), 132–141.
Wilson, C. (2011). Mind controls: A traffic cop on the nerve superhighway. New Scientist. Retrieved September 28, 2023, from https://www.newscientist.com/article/dn20346-mind-controls-a-traffic-cop-on-the-nerve-superhighway/.
About the author
Jeremy Sutton, Ph.D., is a writer and researcher studying the human capacity to push physical and mental limits. His work always remains true to the science beneath, his real-world background in technology, his role as a husband and parent, and his passion as an ultra-marathoner.