Polyvagal Theory – An Introduction

By February 23, 2024Uncategorized

When the Anxiety Increases: An Introduction to Polyvagal Theory


I was never very athletic growing up. Often I came in last or second to last in school races. I was usually picked last for teams unless I made persuasive, pleading eyes at a team captain. People knew I was smart and so they sometimes assumed that translated to sports. It did not. Except for dodgeball. I was very good at dodgeball. The one time I was glad to be last.

Have you ever stopped to think about what is going on in the body in dodgeball or other sports? The brain becomes alert to the rules of the game, to the ball(s) in play, and the body automatically moves. For my level of athleticism, dodgeball was the sweet spot because I didn’t have to outrun the ball, just avoid it.

Polyvagal Theory

Polyvagal theory describes how the autonomic nervous system functions using the sympathetic and parasympathetic nervous systems. Dr. Stephen Porges changed the understanding of the parasympathetic nervous system when he discovered two different functions of the vagus nerve. The vagus nerve runs from our brain down to all of our internal organs and is part of the body’s threat detection system. It constantly tracks and orients to dangers in the environment and changes human physiology to respond in the most effective way to real or perceived threats. It is called our “autonomic nervous system” because it is automatic and operates outside of conscious awareness. We wouldn’t have much luck crossing a busy street (or playing dodgeball) if our autonomic nervous system did not operate without us having to think about it.

The Traffic Light Analogy

There are three states that the autonomic nervous system shifts between to allow humans to adapt to the environment. The simplest explanation for these three states is a traffic light analogy.

Green Light

When we are in a safe environment, meaning there is no real or perceived threat, we enter into the “ventral vagal” state. In this state, the body shifts to a slower heart rate, the middle ears attune to the human voice, facial features, and voice changes to more expression and prosody. One is more positively socially engaged and can feel calm.

Imagine sitting down with your favourite hot drink at the end of the day. You see the sun setting out the window and you take a deep breath with a long exhale because work for the day is done. This is a green light moment. Now imagine your pet jumps up and joins you. The tone of voice you use with your pet is the expressive, prosodic tone of someone in the green zone.

Yellow Light

When we perceive a threat, our bodies become mobilized and activated to manage the threat through our sympathetic nervous system. The “fight or flight” response is what most of us are familiar with here. Our body shifts to support defence through increased heart rate and blood flow to extremities for limb movement. Even hearing focuses on “danger” sounds of high and low frequencies. It is important to note that the body shifts into defence whether a threat is real or perceived. Sometimes the nervous system makes mistakes about what is going on.

Several years ago our family moved to a new house and in the middle of the first night, my husband and I sat up in panic. We were convinced that someone was breaking into the house. After 20 seconds of investigation, we realized that the threat was a refrigerator with an ice machine, something we had never lived with before. Our bodies sensed a threat and responded. Even after we knew we were safe, the cortisol and adrenalin were already rushing through our bodies. It took some time to get back to sleep and for our bodies to catch up to the knowledge that the ice machine posed no threat.

Red Light

When a danger is seen as inescapable, the autonomic nervous system has one other response: to shutdown, immobilize, disconnect, or “play dead”. This red light or dorsal vagal response is the oldest evolutionary response to threat and is easily observed in other species, especially reptiles. Here the body conserves energy through low heart rate and muscle tension, raising pain thresholds as less oxygen flows to the brain.

Understanding that this immobilized state is automatic and instinctual is important. For those who have experienced particular types of trauma, blame and shame may be felt for not “fighting back”.

Polyvagal Theory in Everyday Life

Throughout our day, all three autonomic states show up in varying levels of intensity, whether crossing a busy street, preparing to speak in public, or hearing the irritated tone of voice of a partner. Beyond these stressful moments, the autonomic nervous system is also active in shifting our body in mundane moments like getting out of bed in the morning to more pleasurable moments like play, meditation, and curiosity. Hybrid states where two autonomic states are active at the same time also exist, as shown in this infographic.

Flexibility is Key

Flexibility between states is more important than always being calm or in the green zone. This is self-evident when we stop and think about just how helpful it is to have a heart rate that increases when we are wanting to engage in movement. Yet, because stress and threat can be quite uncomfortable, the yellow and red states often get a bad rap. All three autonomic states are evolutionarily adaptive and help us survive, thrive, and respond to challenges in our world.

In Relationship

Dr. Stephen Porges said, “physiological state [is] an intervening variable influencing behavior and our ability to interact with others.” As we go about our lives we experience our own green, yellow, and red states, but we also engage with others’ green, yellow, and red states. One doesn’t have to go very far in a day to have another person’s yellow state ruin a lovely green moment! It is in those moments when knowledge of human physiology and Bowen family systems theory can be so helpful!

This April, Living Systems will have a conversation with Dr. Porges on his understanding of how these three autonomic states impact how people live in relationships. We will also hear from Victoria Harrison who has spent decades researching physiology in relationships from a Bowen theory perspective. The day will end with a project I have been working on that allows people to track the specifics of their own green, yellow, and red states in daily life and relationships.


Dixie Vandersluys, M.A., C.C.C., is a counsellor based in Manitoba. She is a third-year trainee with Living Systems and recently completed the Polyvagal Institute’s first-ever certificate course.

Thank you for your interest in Bowen Family Systems Theory.

You can read more about Bowen Theory here

Read more about Polyvagal theory here