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  • Writer's pictureMatt Stewart

Polyvagal Theory: How Your Nervous System Shapes Your Perception of the World

Have you ever felt uneasy or threatened in a situation without knowing why? You might notice that no one else seems concerned, yet something still feels off to you.

We're constantly reading thousands of social cues in our surroundings every day. Through our interactions, we pick up on facial expressions, vocal tones, body movements, and more. This constant observation and interaction shape our human experience.

Shaping Our Sense of Self

Our sense of self is molded through these interactions. We learn who to trust and who feels dangerous. Our bodies continuously process this information, influencing our perceptions and reactions.

The Nervous System: Our Body's Surveillance System

Our nervous system is a complex structure that gathers information and coordinates activity throughout the body. It consists of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).

Central Nervous System (CNS)

The CNS includes:

  • Brain: The brain, located in the skull, is made up of billions of interconnected neurons and serves as the coordinating center for nearly all bodily functions and intellectual activity.

  • Spinal Cord: This network of nerve fibers connects most body parts to the brain.

Peripheral Nervous System (PNS)

The PNS includes all nerves outside the brain and spinal cord and is divided into:

  • Somatic Nervous System (Voluntary): This system allows communication between the brain and muscles, enabling movement and sensory feedback.

  • Autonomic Nervous System (Involuntary): This system controls glands and internal organs (e.g., heart, lungs, digestive system) without conscious thought. It regulates essential body functions such as breathing and heart rate.

Reading Danger Cues

The autonomic nervous system (ANS) is always active, performing crucial functions and helping us scan for danger cues. It comprises two systems:

  • Sympathetic Nervous System: This system activates our 'fight or flight' response, preparing the body to react to perceived threats by mobilizing energy and releasing adrenaline.

  • Parasympathetic Nervous System: This system calms the body, conserves energy, and manages 'rest and digest' functions by slowing the heart rate and aiding digestion.

The Role of the Vagus Nerve

Dr. Stephen Porges, a scientist and developer of the Polyvagal Theory, highlights the significance of the vagus nerve. This long nerve, starting at the brainstem, extends through the body and has the widest distribution of any nerve. The vagus nerve plays a critical role in our body's response to safety and danger cues.

Scanning Our Environment

From birth, we instinctively scan our surroundings for safety and danger cues. Babies respond to their caregivers' closeness for safety and react to perceived threats like strangers or loud noises. This scanning continues throughout our lives.


In Polyvagal Theory, neuroception refers to our nervous system's process of reading environmental danger cues. This process occurs involuntarily, much like breathing. The vagus nerve is central to neuroception, with its two branches responding differently:

  • Ventral Vagus Nerve: Responds to safety cues, promoting feelings of physical and emotional security.

  • Dorsal Vagus Nerve: Responds to danger cues, leading to self-protection behaviors, such as freezing or dissociation in extreme danger.

Evolutionary Stages of Response

Porges describes three evolutionary stages in our autonomic nervous system:

  1. Immobilization: The oldest response, causing us to freeze in extreme danger.

  2. Mobilization: Engages the sympathetic nervous system for 'fight or flight' responses.

  3. Social Engagement: The newest response, facilitated by the ventral vagus nerve, enabling connection and feelings of safety.

Hierarchy of Responses in Daily Life

Our response hierarchy is fluid, shifting between states of safety and danger. For instance, we might feel safe and connected in a loved one's embrace but later mobilize to respond to a threat. In extreme cases, danger cues can trigger immobilization, leading to feelings of numbness or dissociation.

Impact of Trauma

Trauma is subjective, meaning what’s traumatic to one person might not be to another. This individual perception of trauma profoundly affects how we see the world, as our experiences are filtered through our nervous system. Trauma survivors often have heightened sensitivity to danger cues, whether these signals indicate a need for mobilization or immobilization.

Mobilization: Fight or Flight

When our body perceives a threat, the sympathetic nervous system springs into action. This "fight or flight" response prepares us to either confront the danger or escape it. Our body releases adrenaline, increasing heart rate and muscle readiness. For trauma survivors, everyday situations can trigger this response, leading to feelings of anxiety, hyper-vigilance, and a constant state of alertness.

Immobilization: Freeze

In contrast, when a threat feels overwhelming, the dorsal vagus nerve might trigger an immobilization response. This "freeze" response can cause the body to shut down, leading to numbness, dissociation, or feeling trapped. Trauma survivors might find themselves freezing in seemingly non-threatening situations, unable to act or respond.

Trauma's Influence on Daily Life

For trauma survivors, these responses play out in everyday life. Simple interactions or minor stressors can trigger significant reactions. For example, a change in someone's tone of voice might prompt a "fight or flight" response, while a crowded room might lead to feelings of immobilization. This constant state of readiness or shutdown can be exhausting and disruptive.

Managing Excess Immobilization

If you frequently feel immobilized or overly sensitive to danger cues, calming the vagus nerve may help. Here are five specific ways to calm the vagus nerve:

  1. Breathing Exercises: Slow, deep breathing can stimulate the parasympathetic nervous system, promoting relaxation. Try techniques like diaphragmatic breathing, where you breathe deeply into your belly, or the 4-7-8 breathing method, where you inhale for 4 seconds, hold for 7 seconds, and exhale for 8 seconds.

  2. Meditation: Regular meditation practice can help calm the nervous system and reduce stress. Mindfulness meditation, where you focus on your breath or a specific sensation, can be particularly effective in calming the vagus nerve.

  3. Cold Exposure: Splashing your face with cold water or taking a cold shower can activate the vagus nerve. The sudden change in temperature can help shift your body from a state of heightened arousal to one of calm.

  4. Progressive Muscle Relaxation: Systematically tense and then relax different muscle groups in your body. Start with your feet and work your way up to your head. Tense each muscle group for 5-10 seconds, then slowly release the tension while focusing on the sensation of relaxation. This practice can help calm the nervous system by promoting relaxation and reducing muscle tension.

  5. Humming or Chanting: Hum or chant slowly and rhythmically, allowing the vibrations to resonate in your chest and throat. Sit comfortably, close your eyes, and take a few deep breaths. Begin to hum or chant a simple sound like "Om" or "Hmm," focusing on the sensation of the vibrations in your body. Continue for 5-10 minutes. This practice stimulates the vagus nerve through the vibrations, promoting a sense of calm and relaxation.

Additionally, psychotherapy can be beneficial, especially for addressing an overactive 'fight-or-flight' response due to past trauma.


Our nervous system is constantly processing information from our environment, shaping our sense of self and influencing our reactions to perceived dangers. The central and peripheral nervous systems work together, with the autonomic nervous system playing a crucial role in our 'fight or flight' and 'rest and digest' responses. The vagus nerve is central to this process, helping us respond to safety and danger cues through its ventral and dorsal branches.

Trauma can profoundly affect how we perceive and respond to these cues, often leading to heightened sensitivity and significant reactions in everyday situations. Understanding the impact of trauma and finding ways to calm the vagus nerve, such as through breathing exercises, meditation, and cold exposure, can help manage these responses and promote a sense of safety and calm.


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