Polyvagal theory is a theory of the autonomic nervous system (ANS) that was developed by Stephen Porges in the 1990s. The ANS is a part of the nervous system that controls our involuntary bodily functions, such as heart rate, breathing, and digestion.

Polyvagal theory proposes that there are three main branches of the ANS: the ventral vagal (or social engagement) system, the dorsal vagal (or immobilization) system, and the sympathetic nervous system.

The ventral vagal system is responsible for social engagement and communication. It is activated when we feel safe and connected to others. The dorsal vagal system is responsible for immobilization and shutdown. It is activated when we feel threatened or in danger. The sympathetic nervous system is responsible for fight-or-flight responses. It is activated when we feel stressed or scared.

Polyvagal theory suggests that our ability to regulate our emotions and behaviors is dependent on the state of our ANS. When we are in a state of social engagement, we are able to think clearly, make rational decisions, and connect with others. When we are in a state of immobilization or shutdown, we are unable to think clearly, make rational decisions, or connect with others.

Polyvagal theory has been used to explain a variety of psychological and physiological phenomena, including:

• Social anxiety disorder: People with social anxiety disorder often have a hyper-activated dorsal vagal system. This means that they are easily triggered into a state of immobilization or shutdown when they are in social situations.

• Post-traumatic stress disorder (PTSD): People with PTSD often have a hypo-activated ventral vagal system. This means that they have difficulty feeling safe and connected to others.

• Heart rate variability: Heart rate variability is a measure of how much our heart rate changes over time. People with a healthy ANS have high heart rate variability. People with a dysregulated ANS have low heart rate variability.

Polyvagal theory is a complex theory, but it has the potential to provide a deeper understanding of the ANS and its role in our emotional and behavioral health.

Here are some resources where you can learn more about polyvagal theory:

• The Polyvagal Theory: Neurophysiological foundations of emotions, attachment, communication, and self-regulation by Stephen W. Porges

• The Polyvagal Theory in Action: Building Resilience in a Challenging World by Deb Dana

• The Polyvagal Revolution: How Understanding Our Autonomic Nervous System Can Help Us Thrive by Stanley Krippner