Immobilized by ME/CFS and/or FM? The Polyvagal Theory, the ANS and Movement Restriction – Health Rising:
another interesting piece connecting autonomic function. A few highlights excerpted below…you’ll probably see why this drew my attention! You can also find tons of other fascinating articles like this one at Health Rising. Their email newsletter is fabulous.
Three (Not Two) Autonomic Nervous Systems:
The Polyvagal Theory splits the autonomic nervous system into three hierarchical systems.
Oldest System – The oldest system is mediated by unmyelinated vagus nerves that originate in the dorsal motor nucleus of the vagus nerve and extend to the viscera below the diaphragm. In humans this system serves two purposes: In a “threat” context, this system is characterized by immobilization, fainting, and dissociating. If you’ve ever walked into a room and suddenly been immobilized with fear, your body had probably invoked the unmyelinated vagal defense system. This is the primitive defensive mechanism frequently observed in reptiles and small rodents and in the opossum in the video. However, when humans are in “safe” contexts, the system works to support the subdiaphragmatic organs (the gut) that promote health, growth, and restoration via the classic “rest and digest” mechanisms.
Next Oldest System – The next oldest system, the familiar sympathetic-adrenal nervous system, actively inhibits the older vagal unmyelinated nerve defense system. When triggered this system also stops digestion and mobilizes energy resources resulting in hypervigilance, increased blood pressure, and tension in the muscles for the “fight or flight” response.
Newest System – The most recently evolved autonomic system is unique to mammals. The myelinated vagus system originates in the Nucleus Ambiguus and is linked to the adrenal system, the heart, and muscles of the face. Usually, the myelinated vagus system calms us and actively inhibits the sympathetic-adrenal system and reduces inflammation while processing our moment-to-moment cardiovascular and metabolic needs.
Putting the Brakes On – Dr. Porges says that we are unconsciously always checking to see whether or not we are in a “safe” social environment. We are always scanning our environment to see if its safe. The myelinated vagus system inhibits the high states of arousal associated with the sympathetic nervous system via something called “the vagal brake“. The vagal brake can be thought of as the pacemaker of our heart. Our normal heart rate would be quite high were it not for the myelinated vagus nerve to inhibit it.
If you have Dysautonomia, this stuff is the center of every day of life, in a very real context. Understanding further connections is essential to the hope of finding better treatment options, and maybe someday, a cure.