What is the Polyvagal Theory?
If you’ve ever read about the Polyvagal Theory, you may have felt confused—it’s complex, and Porges’ explanations of his theory are not simple or easy to understand. In a nutshell, Polyvagal Theory suggests that:
“When challenged, the regulation of the autonomic nervous system sequentially degrades to older circuits as an adaptive attempt to survive.” -Stephen Porges, The Pocket Guide to the Polyvagal Theory, p. 64
When we feel safe and there is no need to defend ourselves, the newest autonomic pathways—the myelinated vagus nerve pathways—are in charge. These pathways facilitate social interaction, growth, and recovery. They can also inhibit the older defense circuits from being triggered.
If we perceive danger, the sympathetic nervous system takes over and we go into fight-or-flight mode. In this state, both branches of the vagus nerve (new myelinated and old unmyelinated) are inhibited.
If our fight-or-flight defense mechanisms don’t make us feel safe, the sympathetic nervous system can become inhibited as the ancient unmyelinated vagus pathways take over. These pathways immobilize us and can make us faint.
When people experience chronic or repeated stress, they can get stuck in fight-or-flight mode. This can result in high blood pressure, elevated levels of stress hormones, anxiety, insomnia, and a host of other issues.
And when people experience trauma, their nervous system tends to shift into the most primitive form of defense—immobilization—and get stuck there. This can lead to a range of psychological problems including dissociation, avoidance, and the inability to communicate, as well as chronic physiological issues involving the organs of the body.
Mammals did not evolve to use this primitive form of defense on a regular basis—that’s what our sympathetic nervous system is for. So as I explained earlier, we are not good at shifting from immobilization back into homeostasis, because we didn’t evolve to have to do it often. When someone’s ancient vagal nerve pathways are activated, it’s very hard for their nervous system to move back into a state of feeling safe. Using what is known about the vagus nerve can allow clinicians to better help their patients who are stuck in this state of immobilization.