Vagus nerve

Vagus nerve is the common name for the tenth cranial nerve, the main nerve of the parasympathetic nervous system. It runs from the brainstem through the neck to the heart, lungs and gut, helping to slow the heart and support digestion while carrying body signals back to the brain.

Its name comes from the Latin word for wandering. Slow breathing with long, gentle exhales is associated with more vagal influence on the heart, visible as greater heart-rate variability. Popular claims about toning or resetting the vagus nerve often go beyond what research currently shows.