Polyvagal Theory (Dorsal Vagal Shutdown)

In order to maintain homeostasis, the autonomic nervous system responds constantly to neural feedback and environmental stimuli. Prior to the introduction of polyvagal theory (by Stephen Porges, PhD), our stress response was seen as a binary: we are either not stressed and operating within our parasympathetic nervous system (PSNS, rest-digest); or we are stressed and operating within our sympathetic nervous system (SNS, fight-flight).

Polyvagal theory is hierarchal and suggests we retained three, not two, primitive neural circuits in the autonomic nervous system. It breaks down our vagus nerve into two branches: retaining the PSNS rest-digest action of the ventral vagus nerve, and adding the freeze-immobilization response of the dorsal vagus nerve.

The human nervous system’s three neural circuits are in a phylogenetically organized hierarchy. In this hierarchy of adaptive responses, Porges’ polyvagal theory hypothesizes that if newer circuits don’t meet the demand, older circuits are recruited. In other words, if we don’t experience calm, social interaction, then the older, more primitive circuits are recruited (fight-flight and freeze-immobilize) sequentially.

Freeze, Fight-Flight and Rest-Digest Responses

The dorsal vagal freeze response, although most newly discovered, is thought to be the oldest response of our nervous system. We access this response when we are unable to escape from danger. In initiating this third, shutdown circuit, we become immobilized or collapse. When high-stress moments hit, people in dorsal vagal freeze response feel an intense need to lie down and/or sleep.

Sympathetic activation is our second oldest neural circuit and is our state of mobilization in response to a dangerous situation; simply put, we fight or flee. Our digestive function is impaired and the body shifts blood from the viscera to the brain and muscles to accommodate the fight-flight that it anticipates.

The ventral vagal complex that initiates rest-digest is the newest addition to our nervous system. It governs social engagement and relaxation. It describes the state of our nervous system in which we can connect to other people, feel empathy, joy, and other emotions. When we are operating in our ventral vagal system, we feel safe and secure.

Health Consequences of Extended SNS Activation

Generally speaking, SNS activation should only be sustained for a short period of time to manage acute stress. Modern life, however, presents us with significant daily stressors, often in multitudes. Polyvagal theory suggests extended SNS activation has many deleterious effects on the body. Not only can dorsal vagal shutdown act alone to immobilize us in response to fear, but when the SNS becomes chronically activated the body turns to the older dorsal vagal branch of the PSNS to modulate this chronic stress.

In effect, the body is putting the lid on its own pressure cooker (stress response) as an action of self-preservation.

Chinese Medicine Diagnosis and Treatment Strategies

In a healthy person, theses three branches of the autonomic nervous system are in constant fluctuation, always working to return the body to a state of homeostasis. The practice of Chinese medicine works similarly, centered around finding balance and homeostasis based on the principle that our mental and physical well-being are intimately intertwined.

One could even say that we treat the body as the subconscious expression of the mind. By treating the physical body, we can treat the whole body-mind. This is where Chinese medicine shines!

A patient operating in dorsal vagal shutdown may feel like they have a chronic, low-grade illness. These patients may be deemed "healthy" by Western medicine because their supporting bloodwork or lab tests do not confirm a disease process, and therefore clinically, this group is easily missed.

Essentially, they experience increased stress, but with lack of evidence in the vital signs. They manifest as feeling despondent, lethargic, hopeless, and shameful, with lack of motivation and follow-through. In fact, they are in a semi-hibernation state of stress response, practically immobilized, all while attempting to carry on with everyday life.

Pattern Diagnosis

There are several basic patterns to consider when treating someone in a chronic dorsal vagal freeze response. It is important to treat not just the pattern diagnosis of the patient, but also incorporate empirical points along the spine that correlate to the dorsal vagal nerve.

1. Kidney Yang or Jing Xu: The kidneys relate to our fear, anxiety and shock. Chinese medicine believes that fear makes qi descend, and a rapid descension of qi may cause the collapse or freeze response.

The kidneys are almost always affected in chronic disease states. Patients with kidney yang xu will present with significant exhaustion, low blood pressure, lethargy, feelings of despondency and cold present in dorsal vagal shutdown.

Kidney yang keeps the heart beating, the blood warm, and aids in digestion by warming the stomach fire and spleen yang. In addition, consider that the kidneys nourish the Curious organs of the brain and spinal cord through the jing.

2. Spleen Qi or Yang Xu: The spleen is highly sensitive to worry and overthinking, which are textbook initiators of dorsal vagal shutdown. These patients have a slow, weak pulse and symptoms like low blood pressure, ineffective digestion, postprandial fullness, distention and diarrhea.

Since the spleen controls the muscles and transports the gu qi, disharmony here may be experienced as extreme fatigue or lassitude and a feeling of heaviness in the limbs that precedes the collapse of the body.

3. Heart Yang Obstruction: If the dorsal vagal shutdown persists, patients may find themselves in a state of heart yang obstruction. When we are well, our state of consciousness reflects a healthy shen, the vital energy housed by the heart. In this case, the patient becomes unconscious in their dorsal vagal shutdown response, effectively becoming catatonic with no agency over their actions.

Empirical Point Guidance

Generally speaking, the dorsal vagal nerve is associated with the mixed cranial nerves around the brain, as well as the spinal nerves between S1-S4. The vagus nerve is also thought to correspond to the yin aspects of the body. Treatment on the head, face, occiput, and sacrum may effectively release a patient from dorsal vagal shutdown response.

In treating the dorsal vagal nerve, we may also need to assess and treat the SNS response. The SNS correlates to the chain of ganglions that run along the back from T1 to L3, the most yang aspect of the back. It is thought that needling along the bladder line and HTJJ in this area exerts a profound influence.

The tissue at T12, L1 and L3 (corresponding to the spleen, stomach and kidneys) is thought to be particularly neurologically sensitive and may support soothing the SNS.

Treatment Approach

We first identify the patient's pattern/diagnosis to determine appropriate points, and then identify key empirical points to add to the treatment. Use fewer needles and gentle technique, approaching with empathy, calm and a light touch.

When treating a patient that you suspect to be in the physiological state of dorsal vagal shutdown, it is important to remember they are in a survival state of self-preservation. This sensitizes them to pain, and the brain can potentially misinterpret facial expressions and normal stimuli as threatening.

The goal is to assist the patient in returning to their PSNS rest-digest; to a state of calm, social engagement with reduced pain.