The wonder of the ‘wanderer’ vagus nerve

By Florence Bowen, DOMP

The vagus nerve is one of the twelve cranial nerves of the body and it is one of the longest nerves in your entire body. The vagus nerve is the tenth cranial nerve. It originates in the brainstem and carries nerve fibers that transmit and mediate information from throughout the body, specifically your organs, to the brain (Zagon, 2001).

From the brainstem, located at the base of your skull, the left and right branches of the vagus nerve make their way down the neck, upper chest, lower chest, and diaphragm to the abdominal cavity (Krahl, 2012). During its journey down into the abdomen, branches innervate (activate) structures such as, the larynx, pharynx, heart, lungs, stomach, liver, pancreas and  intestines. The majority of your organs are controlled by this one nerve.

The vagus nerve is responsible for the regulation of internal organ functions, such as digestion, heart rate, and respiratory rate, as well as vasomotor activity, and certain reflex actions, such as coughing, sneezing, swallowing, and vomiting.

New evidence demonstrates that the vagus nerve, supplies motor and sensory innervation to thoracic diaphragm, the large dome shaped muscle at the bottom of your ribcage that helps you breathe (Young, Page, Cooper, Frisby, & Blackshaw, 2010).

Stimulation of the vagus nerve elicits a calming effect in the body. This is because the vagus nerve makes up the majority of the parasympathetic nervous system of the body. The parasympathetic portion of our nervous system allows us to calm down, it lowers our blood pressure, promotes digestion and elimination, also known as our “rest-and-digest” mode.

So, how can we promote more of the calming effects of the vagus nerve in our own bodies?

Osteopathic Manual Therapy (OMT)

The calming effects of OMT have been demonstrated in preterm infants, whom after 5 minutes of osteopathic touch, demonstrated significantly lower heart rates and increased oxygen saturation levels. What this specific study demonstrated was that OMT had a positive effect on the autonomic nervous system and promoted parasympathetic activity in the preterm infants. The calming effects of OMT have been noted in not only premature infants but adults too. Osteopathic physicians, Henley et al. (2008) noted that even when a patient was placed in a position that stimulated the sympathetic nervous system, such as a 50-degree head tilt-up, the vagal (calming) response of the manual application of osteopathic treatment was strong enough to overcome the sympathetic tone and promoted parasympathetic activity.

Deep Breathing

The thoracic diaphragm, our breathing muscle, is activated by the vagus nerve. Breathing, stimulates the vagus nerve and stimulation of the vagus nerve elicits a calming effect.

Slow, deep, belly breaths with longer exhalation phases leads to an increase in parasympathetic tone.

When our vagus nerve is stimulated our parasympathetic nervous system is active, we feel calm, at ease and rested. It encourages us to slow down, quite literally. Our heart rate slows, our breath deepens, our stomach and intestines are able to process, digest, move and eliminate. Not sure what it really feels like to be in parasympathetic mode? When you are relaxing in corpses pose at the end of a yoga class, you are likely in more of a parasympathetic state. Meditation, breath work, yoga, gentle and subtle manual therapy like Osteopathy can all encourage you to achieve that parasympathetic state.

References:

Henley, C.E., Ivins, D., Mills, M. et al. Osteopathic manipulative treatment and its relationship to autonomic nervous system activity as demonstrated by heart rate variability: a repeated measures study. Osteopath Med Prim Care 2, 7 (2008). https://doi.org/10.1186/1750-4732-2-7

Krahl SE. Vagus nerve stimulation for epilepsy: A review of the peripheral mechanisms. Surg Neurol Int. 2012;3(Suppl S1):47–52.

Krygier JR, Heathers JAJ, Shahrestani S, Abbott M, Gross JJ, Kemp AH. Mindfulness meditation, well-being, and heart rate variability: a preliminary investigation into the impact of intensive Vipassana meditation. Int J Psychophysiol (2013) 89:30513.10.1016/j.ijpsycho.2013.06.017.

Manzotti, A., Cerritelli, F., Lombardi, E., La Rocca, S., Chiera, M., Galli, M., & Lista, G. (2020). Effects of osteopathic treatment versus static touch on heart rate and oxygen saturation in premature babies: A randomized controlled trial. Complementary Therapies in Clinical Practice, 39, 101116.

Young, R. L., Page, A. J., Cooper, N. J., Frisby, C. L., & Blackshaw, L. A. (2010). Sensory and motor innervation of the crural diaphragm by the vagus nerves. Gastroenterology, 138(3), 1091-1101.

Zagon A. Does the vagus nerve mediate the sixth sense? Trends Neurosc. 2001;24(11):671–673