Polyvagal theory, developed by Stephen Porges, explains that our autonomic nervous system constantly scans our interactions with the environment and others to ensure our survival. This scan occurs automatically, without the intervention of the rational brain, based on our perceptions of the environment, and can induce 3 distinct physiological states:

• The Ventral Vagal State In this state, you naturally seek social interactions, you are able to connect with others and feel connected. In this state, you feel supported by the group, you trust life and others, you feel free to be yourself. (This is the gentle brake). The frontal area of the brain is activated. Physiologically:
  • You are relaxed, energetic, with a rather slow and regular heart rate. Blood pressure and digestion are optimal. Muscles are relaxed.
  • Your breathing is slow, deep, and regular.
  • Facial expression is flexible, adapted to interactions.
  • You can inhibit background noise to focus on the frequency of the voices of people around you.
  • Your own voice follows a melody (prosody) and you have a sound volume appropriate for verbal communication of your thoughts, feelings, and emotions.

• The Sympathetic State. In this state, you feel stress and you are alert to danger; social engagement is harder because you think more about how to react (fight or flight). Prefrontal cortex activity is reduced, with the brain prioritizing survival over rational thought. Physiologically:

• You are agitated, you have a surge of energy (“stress response”).
• Your heart rate and blood pressure increase, and blood is primarily directed to your legs and arms. Muscles are tense, ready to act.
• Your breathing is faster or shallower.
• Digestion is interrupted and salivation reduced. If this state becomes chronic, you may lose appetite or experience nausea.
• Your facial expression is rigid, inflexible. Your cheeks flush.
• You can no longer inhibit background noise, which becomes overwhelming, because your nervous system, in a state of hypervigilance, tunes into frequencies lower and higher than the human voice, in order to detect the presence of danger.
• Your voice is shrill, at too high a volume.

• The Dorsal Vagal State. Your body feels unable to act, without a solution (freeze/immobilization). In this state, you feel profound helplessness, a freezing or disconnection from the body, and you are so overwhelmed by stress that your body collapses: it plays “dead” in the face of the environment and others (this is an abrupt brake). The prefrontal cortex is largely inactive, severely hindering rational thought and communication. Physiologically:
  • You can no longer communicate.
  • Your energy is very low, you feel exhausted, and, in the long run, you will tend to suffer from chronic fatigue.
  • Your breathing is slower, shallower, irregular.
  • Your heart rate and blood pressure slow down, which can lead to discomfort.
  • You lose control of your bladder and intestines.
  • Your face is expressionless and pale.
  • You no longer react to ambient noises, especially attempts to communicate with you.
  • Your voice is monotone, at a very low volume.