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The Polyvagal Theory

Understanding how your autonomic nervous system influences behaviour

The autonomic nervous system, made up of the parasympathetic and sympathetic nervous systems, is responsible for regulating involuntary bodily functions such as breathing, heartbeat and digestive functions. Created by Dr. Stephen Porges, Polyvagal Theory posits that the parasympathetic vagus nerve has two functionally different circuits — the ventral vagal and the dorsal vagal  rather than one. 


Why Polyvagal Theory is Useful


The polyvagal theory helps us understand the three hierarchically organized physiological states that determine our lived experience:


  • The connection to self and others  — ventral vagal parasympathetic system;

  • The fight/flight  — sympathetic nervous system;

  • The immobilization or collapse  — dorsal vagal parasympathetic system.


The theory also gives us insight into the nature of the stories we all tell ourselves. Only one autonomic state is in control of our system at any given moment. Whether the story is hope-filled or hopeless is determined by the physiological state in which we find ourselves. 


Below the level of conscious thought, your autonomic nervous system acts like a personal surveillance system constantly scanning inside your body, outside in the environment and between you and others for signals of safety or danger.


Ventral Vagal


Human beings come into the world hardwired for connection to others. Similar to other mammals, babies are not able to survive and develop to their full potential without caregivers who nurture them and support their development process.  Connection among humans is not just nice to have, it is a biological imperative. 


Human evolution led to the development of the ventral vagal system giving us the capacity to downregulate defensive reactions to feel safe with others. When below the level of conscious thought our nervous system detects a preponderance of cues of safety, we can connect to our cognitive, creative and intuitive capacities, and to our ability to collaborate with others.


Sympathetic/ Dorsal Vagal


When cues of danger outweigh cues of safety, the parameters of our emotions, thoughts and behaviours are limited by the defensive physiological state (sympathetic or dorsal) in which we find ourselves. While not necessarily conscious of what was happening at the level of the nervous system, we have all experienced the results of a takeover by the sympathetic nervous system as the body fills with adrenaline and cortisol preparing it to act in the face of a felt sense of danger. Likewise, we have all experienced the sense of being overwhelmed and loss of agency that accompanies a state of dorsal collapse.


Reshaping our Autonomic Nervous System


Our nervous system develops based on our lived experience, and over time it becomes very sensitively tuned to recognize situations that have meant danger in the past. This can result in a “misattuned” nervous system that may trigger defensive reactions when there is no objective danger present in the situation. The good news is that we can reshape our autonomic nervous system. Learning to understand and befriend your own nervous system gives you the ability to consciously choose how you wish to respond in a given situation. 

"Once you understand the role of the autonomic nervous system in shaping our lives, you can never again not see the world through that lens." (Deb Dana 2018)


Deb Dana (registered therapist, author and teacher) has been a close collaborator of Dr. Porges for many years. She has pioneered a very down-to-earth approach to supporting clients in integrating the basic tenets of Polyvagal Theory into everyday life. 


I have been trained by Deb Dana and in 2021 was one of the first group of trainers delivering the Rhythms of Regulation: Foundations of Polyvagal Informed Practice Part 1 course offered through the Polyvagal Institute. The polyvagal informed approach has become a cornerstone of my practice working with clients.


For a deeper introduction to Polyvagal Theory, I recommend you read Deb Dana's excellent short article, A Beginner's Guide to Polyvagal Theory (see link below), and if you are interested in understanding more about the relationship between the autonomic nervous system and trauma,  watch this nine-minute animated video from the Trauma Foundation and the Polyvagal Institute. 


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