What Is Polyvagal Theory and How Can It Help You Manage Stress and Trauma?

Episode 35: Behind the Therapy Door

This article draws on a conversation between therapists Sarah Thome and Matt Gallagher. Listen to the full episode for the stories behind the takeaways.

Your stomach drops before a difficult conversation. Your throat tightens when you try to speak up in a meeting. Your knees go weak when the phone rings at 2 a.m. These are not character flaws or anxiety disorders. They are your autonomic nervous system doing exactly what it was designed to do, and polyvagal theory explains why.

Related: About Sarah and Matt.

What Is Polyvagal Theory and Who Developed It?

Polyvagal theory was developed by neuroscientist Stephen Porges and describes how the vagus nerve (the largest nerve highway in your body, running from your brainstem to your major organs) governs three distinct nervous system states. It is not a cure. It is a framework for understanding why your body does what it does under stress, and that understanding alone can reduce shame and open the door to healing.

Therapists use polyvagal theory with trauma clients, first responders, and anyone stuck in chronic stress, because once you understand why your body is reacting, you can start learning to shift out of it.

Related: What is the Process Communication Model®?.

What Are the Three Branches of the Autonomic Nervous System?

Polyvagal theory identifies three branches, each with a distinct function and a recognizable set of physical sensations.

Ventral vagal (above the diaphragm): This is your social engagement system. When you are in ventral vagal, you feel safe, connected, curious, and creative. Your facial muscles are relaxed, your voice has natural prosody, and you can make eye contact without effort. This is where healing happens.

Sympathetic (fight or flight): This is your mobilization system. Heart rate increases, muscles tense, breathing becomes shallow. You are scanning for threats and preparing to act. This state is not inherently bad; it is what gets you out of danger. It becomes a problem when your body stays here long after the threat has passed.

Dorsal vagal (below the diaphragm): This is your shutdown system. When the threat is overwhelming and you cannot fight or flee, your system collapses into freeze, numbness, or dissociation. Energy drops. You feel flat, disconnected, or “gone.” In healthy doses, this branch also governs rest and digestion.

Related: Why does my anxiety get worse when I relax?.

How Does Trauma Get “Stuck” in the Nervous System?

Here is a distinction worth holding onto, from Matt Gallagher, LCPC: “The difference between grief and trauma is this: grief is about something that has happened. Trauma feels like it’s still happening in the body.”

When a traumatic event overwhelms the nervous system’s capacity to process it, the body can get locked in a sympathetic or dorsal vagal state. The event ended, but the body does not know that. You may find yourself hypervigilant, easily startled, or chronically numb, not because something is wrong with you, but because your nervous system is still protecting you from something that is no longer there.

This is why talk therapy alone sometimes feels insufficient for trauma. You can understand your trauma intellectually and still feel it in your body. Polyvagal theory explains the gap.

Related: Why can’t I stop reliving the past?.

What Is Neuroception and Why Does It Matter for Therapy?

Neuroception is the autonomic nervous system’s unconscious scanning for cues of safety or danger. It happens below awareness: before you think, before you choose, your body has already decided whether the environment is safe. This is why you can walk into a room and feel uneasy without being able to explain why.

In therapy, neuroception means that genuine felt safety in the therapeutic relationship is a prerequisite for deep trauma work. If the client’s system does not register safety, regardless of what the therapist says, the body will not allow access to stored trauma. That is why Sarah Thome, LSCSW, says, “I cannot emphasize the importance of a healthy therapist-client relationship enough.”

Related: Why the therapeutic relationship matters more than the method.

“Grief is about something that has happened. Trauma feels like it’s still happening in the body.”

Matt Gallagher, Behind the Therapy Door

What Practical Techniques Help Regulate the Nervous System?

Sarah and Matt share several techniques they use in clinical practice to help clients shift between nervous system states.

Breathwork

Connect your inhale with your exhale. Hold for a second, then exhale a second longer than you inhaled. Move that breath into the tightest parts of your body and feel it moving through that spot. People often say afterward, “I feel lighter. I feel calmer.”

Olfactory Grounding

Inhaling essential oils or smelling salts activates the olfactory nerve, which is the closest sensory pathway to the limbic system and bypasses the thalamus entirely. Sarah uses this technique to manage abreactions, the unexpected intense activation that can surface during trauma processing.

Visualization Modulation

Mute the sound. Strip the audio from your mental replay of the event. Other ways to dilute the intensity: turn the scene black-and-white, turn your back to it so you can sense it without looking straight at it, or run it backwards from the worst point to the beginning. You would be surprised what you can handle with a little gentle prompting.

Physical Grounding

Feet flat on the floor. Change your posture. Stand up and move. These simple physical shifts can disrupt the “stuckness” of a dorsal vagal freeze response and restore a sense of agency in the body.

Brainspotting

Resource spots and activated spots provide two anchors the client can toggle between, building the capacity to shift states deliberately rather than being hijacked by them.

How Does PCM® Personality Type Affect Nervous System Responses?

Different personality types experience nervous system activation differently. Sarah and Matt reference several patterns from their clinical practice.

• Persister energy: when another part of you is uncomfortable, the Persister refuses to give in and doubles down
• Harmonizer base: often recognizes limits only after too many people have crossed their boundaries, and it shows up as exhaustion or sadness
• Rebel energy: may resist using calming tools and just want to stop feeling what they are feeling: “I hate this.”
• Persister and Thinker energy: tends to recognize limits only after blowing past them (on a long weekend away, Matt does not even fish the first day, because that feels like work)

Understanding your personality type does not change your nervous system, but it helps you recognize which state you tend to get stuck in and why your default coping strategies may not be working.

Why Is Tolerating Stillness a Trainable Skill?

Both hosts challenge listeners to practice five to ten minutes daily of deliberate stillness: no phone, no podcast, no multitasking. Modern life’s constant stimulation erodes the capacity to sit in ventral vagal safety, which is exactly the state the nervous system needs for recovery.

Expect to feel antsy at first. Sarah does too, and she has to pursue stillness on purpose before her body shifts back into, “Oh, I’m okay.” If total silence is too much, go outside: a few birds and a breeze can give you just enough input to stay grounded. Or sit by a fire pit with a book you never open and just stare at the fire.

Can Talk Therapy Alone Resolve Stored Trauma?

Sarah and Matt are direct about this: talk therapy is incredibly valuable, but if you have been in supportive talk therapy for years and still feel stuck, you may need specialized trauma processing. EMDR, brainspotting, and somatic approaches target the stored physiological pain that talking about the event cannot reach.

Their recommendation: even if you love your current therapist, consider doing some sessions with a trauma specialist to clear stored pain, then return to your regular therapist. The two approaches complement each other.

Trauma can be healed. There is hope.

Related: How do you know when therapy is done?.

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