Post Traumatic Stress – Nervous System

Fight – Flight – Freeze  (Immobilize) – Collapse

“Immobilization is a hardwired reaction, not a personal fault.” Stephen Porges

Poly Vagal Theory 

Science keeps evolving and Dr Stephen Porges has recently published his findings on the Poly Vagal theory which really validates the freeze state that many people with complex trauma or PTSD symptoms have experienced when under threat. Dr. Porges explains that the old system of explaining threat poses that the sympathetic system when under high stress causes one to fight or flight and therefore we need to calm the sympathetic system down. Dr. Porges explains that in fact sticking to that theory does not acknowledge that the body has a defensive system of shutting down (immobilizing ), which is connected to our reptilian brain (our primary defense system). In the worst case scenario immobilization can kill a person by causing the heart to slow down enough that it stops.

An example of this would be a cat swatting a mouse until it immobilizes  ( seemingly dead). Once the mouse awakens again and the cat continues to swat at it, the mouse immobilizes again, only this time for a much longer period and in some cases immobilizes until dead.

Dr Porges states, ” that when we are under life threat we get the old vagus deification and passing out. When the vagus is deregulated we get ” gut problems, constipation, diarrhea, inflammatory bowel and other gut diseases,” (Porges, 2011)

Poly vagal theory articulates that we have two defense systems fight flight and immobilization or freeze.

Overview of Autonomic Nervous System

Autonomic Nervous System

It’s a part of the peripheral nervous system, regulates internal organ functions, such as heart rate, digestion rate and pupil dilation.

The ANS is usually conceptualized as consisting of two branches, nervous systems.
The Sympathetic and Parasympathetic

The sympathetic nervous system activates the body, especially during emergencies (“fight-or-flight”)
The parasympathetic is calming (“rest-and-digest”).

The balance between the two systems is usually said to determine ANS functioning.

The Ventral Vagus Nerve

Dr. Porges speaks to the vagus nerve and its role, through its branches, in regulating the heart, face, abdominal viscera and breath. It also communicates with the brain.

Vagus Nerve
The Vagus Nerve
“Social Engagement” and Conflict Resolution

The vagus nerve, or more precisely the ventral branch of the vagus nerve, controls the muscles of the face, heart and lungs — parts of the body used to interact with others. This is also known as the mammalian system what Porges calls “social engagement.”

According to Dr. Porges, social engagement, tends to “down regulate” (calm) the sympathetic nervous system, and the fight/flight response.

The Dorsal Vagus Nerve

Another branch of the vagus, the dorsal vagus, regulates organs below the diaphragm. It is instrumental in activating the “shutdown” of the body seen in cases of overwhelming trauma. From an evolutionary standpoint, this is a much older part of the nervous system (Porges, 2011).

Hierarchy of adaptive responses to trauma.

As Mammals we tend to react in milliseconds. In other words I was scared of the bear because I ran. Dr. Porges explains that our nervous system adapts to the threat in a hierarchy. First as mammals when under threat we socially engage, if this doesn’t work then we fight or flight and finally if this does not work we immobilize or freeze.


1)  Social engagement

2)  Fight/flight


3)  Freeze /immobilize (oldest response connected to our reptilian days).

We use immobilizing when social engagement, fight flight does not work.

What happens when the nervous system is under threat?

According to Dr. Porges “the neural regulation of the striated muscles in the face and head got turned off,” (Porges,2011) This means that the ear is tuned in to listen for a predator which means that being in a noisy crowded room or mall is disturbing because lower toned noises are pronounced. The facial nerves are no longer engaged (flat affect) in order to be tuned in to the predator.

“Their nervous system is a neuroceptive state that has great advantages in detecting a predator, but is totally compromised in being social, ” (Porges,  2011).

“For those who have had repeated trauma, I would basically say that in the single-trial trauma reaction of shutting down, the person is normal or typical before this event and after the event the person can’t go to public places, starts having all the symptoms of lower-gut issues, can’t deal with proximity with others, is hypersensitive to low-frequency sounds and even has severe issues of fibromyalgia and blood-pressure regulation,” (Porges, 2011).

This means that persons who are living with PTSD symptoms who are also diagnosed with Agoraphobia are actually adapting exactly the way their nervous system intends them to adapt. Avoiding social engagement because of the sensitivity to sounds, and the facial muscles remaining flat which makes for poor social engagement anyways.

Regulating the parasympathetic nervous system becomes imperative then in treatment for PTSD.

Dr. Stephen Porges suggestions for Vagal calming.

Neuro Exercises that bring us back to baseline~


Connecting with others. Do try to socially engage. It will actually calm the Vagal nerve.

Play with your dog.

Play with your children

Gregorian Chants are calming to the Vagal nerve and permit the ear to move back to a normal state.

Disney Songs (higher intonations in voice).

Healthy relationships where we feel nurtured and loved.

Playing an instrument that requires breath control.


Singing in a choir.



Borrowed from Beyond the brain : How the vagal system holds the secret to trauma. A Webinar Session with Ruth Buczynski, PhD and Stephen Porges, PhD

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