A dorsal vagal shutdown is an involuntary nervous system response to extreme stress, overwhelm or a traumatic event. A shutdown is also known as collapse and is connected to the freeze response, which is as common and normal as fight and flight-activations. Freeze is a reaction to survive what the body interprets as an immediate threat or intense overwhelm that is psychologically or physically threatening.

The freeze usually refers to the body’s immediate survival mechanism during a traumatic or overwhelmingly stressful event. Shutdown most often refers to a prolonged collapsed state, spanning months or years, that the nervous system enters when someone has not been able to recover from either a traumatic event, an extended period of smaller traumatic events and/or extended stress without relief.  

Some symptoms of a dorsal vagal shutdown are: 

• Numbness
• Inability to feel or identify emotions
• Constant and/or extreme fatigue and exhaustion
• Sudden, overwhelming fatigue
• Significant sleep changes (excessive sleep, insomnia or changes in sleep schedule)
• Changes in appetite or low to no appetite
• Difficulty speaking
• Decreased heart rate and/or blood pressure
• Possible fainting
• Unable to accomplish regular tasks despite desire
• Brain fog
• Muscle weakness
• Inability to make small or big decisions

A prolonged shutdown can affect relationships, self-esteem, engagement with daily life and employment. Dorsal vagal shutdown, as well as all nervous system responses, is a safety-seeking response, so it’s important to recognize that each nervous system response is valid and gives valuable information for treatment and recovery.

The Dorsal Vagal System 

The dorsal vagus is the underside of the vagus nerve, which is a cranial nerve that is part of the parasympathetic nervous system. Everyone’s nervous system is comprised of the following:

• The central nervous system: this is made up of the brain, optic nerve and spinal cord
• Peripheral nervous system: this includes all other nervous systems in the body that aren’t the brain and spinal cord
  • Somatic nervous system: this is part of the peripheral nervous system and includes touch, taste, sound and smell (sight is part of the central nervous system) as well as all muscles that can be consciously controlled
  • Autonomic nervous system: also part of the peripheral nervous system, this controls the involuntary processes of most organ functions
    • The sympathetic nervous system: when in stress or immediate danger, this system acts as an alarm bell and activates the fight or flight response
    • Parasympathetic nervous system: this is often called the “rest and digest” system, as it has the opposite function of the sympathetic nervous system, where it brings the body back to balance and recovery
      • Ventral vagus: this is the front of the vagus nerve and allows for social connection by picking up on safety clues in the environment, creating greater regulation and recovery from sympathetic nervous system activation
      • Dorsal vagus nerve: the back of the vagus nerve, the dorsal vagus initiates immobilization and is the oldest mammalian survival mechanism

Dorsal vagal activation—freeze or immobilization—can be seen in most mammals, usually in prey/predator situations, and looks like playing dead. Mammals other than humans can also enter a prolonged state of shutdown, where they do not fully recover from dorsal vagal activation, and this is most often seen as a consequence of traumatic situations, such as captivity, isolation and/or abuse.

The positive functioning aspect of the dorsal vagal system is as a pendulum between arousal and rest, inducing deep, restorative relaxation, cues appropriate digestive signals (hunger and satiety) and aiding in sleep. It also triggers the mammalian diving reflex, which allows the human body to relax underwater and hold longer breaths and for aquatic mammals to hold their breath for extended periods of time.

Going in and out of a window of tolerance every now and then is normal, and this undulation is a sign of a well-regulated nervous system, as it means that the body retains appropriate sensitivity to stress yet can return to a regulated state. Remaining in shutdown without returning to a state of stasis indicates that the person is operating in a state of overwhelm and requires co-regulation and somatic interventions.

Co-regulation, Polyvagal Theory and Veterans

Nervous system recovery within Dr. Stephen Porges’s polyvagal theory is found in social engagement through co-regulation. Co-regulation is an interactive process between two or more people that helps each individual regulate, adapt and adjust their emotions and behaviors in a way that is soothing and allows the individual to manage internal and external stressors or difficult situations and emotions. Co-regulation happens from birth and is an evolutionary adaptation in humans and other mammals. Successful co-regulation is the contented feeling people get after spending time with friends and loved ones or even attending a class or group activity, such as an exercise, yoga or gardening class or support groups. Problems or stressors that were present before spending time with others in a positive setting still exist, but the nervous system is calmer and better equipped to handle the stressors and find solutions.

 Veterans can face multiple hardships post-service, including living with trauma symptoms, post-traumatic stress disorder (PTSD), moral injury and the anxiety and depression that can come with reintegration to civilian life, notably the loss of camaraderie and culture they had during their service. As researchers continue to gain a better understanding of the mechanisms of trauma and how untreated trauma impacts a person’s life, there is also a greater understanding of the vital roles that the nervous system and supportive social engagement play in treating trauma.

Pyramid Military Therapy & Recovery Programs applies polyvagal theory to treat trauma in veterans in tandem with other evidence-based treatment modalities. Our veteran-only program allows veterans to connect with each other and offer mutual support through shared understanding and experience, which are vital to healing and recovery.

Click here to learn more and connect with one of our admission specialists.