Vagus Nerve: The Master Regulator of Healing The vagus nerve — the tenth cranial nerve and the longest nerve in the autonomic nervous system — extends from the brainstem through the neck, chest, and abdomen, innervating the heart, lungs, oesophagus, stomach, liver, gallbladder, spleen, pancreas, and the entire length of the intestines, carrying both efferent signals from the brain to peripheral organs and, critically, 80% afferent signals from the organs back to the brain. As the primary conduit of the parasympathetic nervous system, vagal tone — the level of ongoing vagal activity measurable through heart rate variability (HRV) — determines the body's capacity to maintain anti-inflammatory homeostasis via the 'inflammatory reflex', regulate intestinal motility and gut microbiome composition, manage the stress response through HPA axis modulation, and facilitate the restorative 'rest and digest' physiology that enables tissue repair. Chronic vagal dysfunction — driven by psychological trauma, chronic inflammation, gut dysbiosis, toxic exposure, and sedentary behaviour — is now identified as a common denominator across conditions including autoimmune disease, inflammatory bowel disease, treatment-resistant depression, PTSD, and ME/CFS, making vagal rehabilitation through evidence-based practices a critical and underutilised therapeutic frontier.
#vagus nerve #parasympathetic
