3 Simple, Powerful Ways to Activate the Healing Power of the Vagus Nerve
Many stress reduction techniques, like meditation and exercise, take energy that I rarely have, as someone who lives with a chronic illness. That has left me wondering: is there a simple, direct way to reduce stress? It turns out there is, and it's called vagus nerve stimulation.
What we call the vagus nerve is actually a web of nerve fibers connecting the brain to many of the key organs and systems in the body. Vagus is Latin for 'wandering' (think vagabond), which is an appropriate name for a nerve that links so many different parts of the body and influences so many bodily functions.
Why should you be interested in the vagus nerve if you have a chronic illness? The vagus nerve appears to be under-activated in certain chronic illnesses, although it is unclear whether this is a cause of, or effect from, illness.(1)Regardless, living with illness is stressful, and experts have long recommended stress management as an effective tool for reducing unrest, pain, and insomnia. However, to heal from chronic stress, the vagus nerve needs to be activated. Fortunately, there are several easy, natural ways to stimulate your vagus nerve.
What Does the Vagus Nerve Do?
The vagus nerve directs the motor function of neck muscles, including speech and swallowing. It provides sensory input from the throat, heart, lungs, and abdomen to the brain. Perhaps most importantly, it is responsible for key functions in your cardiovascular system, immune system, digestive system, and whole-body stress response.(2)In order to fully understand how the vagus nerve is involved in your stress response, we need to know more about the autonomic nervous system.
The autonomic nervous system governs unconscious bodily processes, like organ system function, and instinctive reflexes. We can divide the autonomic nervous system into the sympathetic nervous system and the parasympathetic nervous system.
The vagus nerve governs the "rest and digest" parasympathetic nervous system, meaning that the nerve is activated to promote relaxation, recuperation from episodes of distress, digestion, and immune activity, among many other vital functions. This is the opposite of the sympathetic nervous system, which triggers your "fight or flight" stress response—the muscle tensing, heart pumping, shallow breathing, sweaty-palmed reaction to danger. The vagus nerve is involved in balancing sympathetic and parasympathetic activity. However, here we will focus primarily on its role in the parasympathetic nervous system.
How the Vagus Nerve Governs the Parasympathetic Nervous System
Cardiovascular System - the vagus nerve is deeply involved in regulating breath and heartbeat. When your lungs expand during inhalation, the vagus nerve carries signals to your brain about your breathing rate. Your brain modifies your heart rate accordingly, by sending signals back along the vagus nerve to your heart during the next exhalation. Thus, when your breathing slows, your heart rate slows, blood pressure drops, and you feel relaxed.(3) When your breathing quickens, your heart rate and blood pressure increase, and you feel agitated. Critically, while you exhale, your vagal nerve activity is at its highest, and your heart rate is at its lowest.
Scientists can measure the difference in your heart rate between in-breath (when it is faster) and out-breath (when it slows). This measurement is called heart rate variability (HRV), and it has proven to be a powerful predictor of overall health and well-being. HRV is a proxy for vagal activity. High HRV, meaning a high variation in heart rate between inhalation and exhalation, correlates to being more relaxed, when your parasympathetic nervous system dominates. Low HRV, meaning a low variation in heart rate between inhalation and exhalation, is a sign of intense activity. If you are exercising, a low HRV is a good thing; you want your sympathetic nervous system to energize you when you're in motion. However, if you are sitting still, a low HRV is a sign of anxiety, hypervigilance, and being in a fight-or-flight state. Low HRV is a common finding in chronic illness.(4)
Immune System - the vagus nerve can trigger the release of immune calming biochemicals, which turn off inflammation in the body.(5) Inflammation causes or exacerbates many chronic diseases, so finding ways to reduce it is very beneficial for your overall health.
Digestive System - activated vagal nerve fibers in the digestive tract are partly responsible for "gut feelings." Vagal activation promotes gut motility and regularity, reduces intestinal inflammation, affects appetite, and monitors integrity of the gut lining.(6) Finally, fascinating new research suggests that the vagal nerve may link the gut microbiome with the brain, with consequences for feelings like moderating anxiety.(7)
3 Ways to Activate the Vagus Nerve
Humming or Singing
When your vocal cords vibrate, they stimulate your vagus nerve where it passes near the carotid artery on its path from the brain to the body.(8) Humming or singing may seem like a simple way to promote relaxation, but it has deep roots in contemplative practices like praying the rosary and meditative chanting (Om is a traditional humming chant).(9)
Medical devices placed in the ear use electrical pulses to stimulate a branch of the vagus nerve that connects the ear to the brain. Studies have shown that these devices can help treat several mental and physical illnesses by reducing activity in the limbic brain system, which processes stress and emotion, like the amygdala and hippocampus.(10) The amygdala is the threat detection centre in the brain, which triggers the fight-or-flight response when danger in the immediate environment is perceived.
Researchers wanted to know whether Om chanting, which stimulates vibration sensations around the ears, could create a similar effect. They conducted a pilot study which trained volunteers to chant "O" for five seconds, then "M" for 10 seconds, while imaging their brain activity using fMRI, and compared results against a sham control chant. (11) As expected, significant deactivation was observed in the amygdala and hippocampus, while participants chanted Om. The study demonstrated that it only took a few minutes of chanting to deactivate the amygdala.
If singing in the shower or humming along to your favourite playlist is more your style, rest assured that they will likely stimulate your vagus nerve too. Gargling warm salted water is another simple way to stimulate vagal activity. Similar to humming, loudly gargling massages the vagus nerve fibers as they pass through the ear and carotid neck region, activating them.
Splashing cold water on your face, laying a cold compress (such as a cold, wet face cloth) on your neck, or taking a cold shower are all ways to stimulate the vagus nerve. A recent study demonstrated that applying cold stimulation to the neck, which is innervated by the vagus nerve, activated the parasympathetic nervous system. The researchers found that heart rate variability, which indirectly measures vagus nerve activity, increased, which meant that "rest and digest" response was triggered.(12) The investigators recommended cold exposure as a simple way to manage stress.
The key factor for stimulating the vagus nerve using the breath is that the exhalation must be longer than the inhalation. Exhalation is when vagal activity is highest, and heart rate is lowest, which is why it is important to prolong your out-breath. Diaphragmatic deep-belly breathing is preferable for stimulating vagal tone. If you are too tired for meditation, even one minute of deep breathing can help stimulate your parasympathetic nervous system, such as 4 seconds in and 6 seconds out. Research has suggested that the most relaxing breath rate is six times per minute. This breathing rhythm was the most common rate measured during a study, as participants said mantras while meditating or repeated the Ava Maria prayer.(13)
While meditation may not be your cup of tea, these vagus nerve stimulation ideas might be an answer.
1.Johnson, Cort. HealthRising.org. 1/11/2016.
4. Meeus M, Goubert D, De Backer F, Struyf F, Hermans L, Coppieters I, De Wandele I, Da Silva H, Calders P. Semin Arthritis Rheum. 2013 Oct;43(2):279-87. doi: 10.1016/j.semarthrit.2013.03.004.
5. Johnson, Cort. HealthRising.org. 1/11/2016.
7. Breit, Sigrid et al. “Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders.” Frontiers in psychiatry vol. 9 44. 13 Mar. 2018, doi:10.3389/fpsyt.2018.00044
9. Johnson, Cort. HealthRising.org. 1/11/2016.
10. Kalyani, Bangalore G et al. “Neurohemodynamic correlates of 'OM' chanting: A pilot functional magnetic resonance imaging study.” International journal of yoga vol. 4,1 (2011): 3-6. doi:10.4103/0973-6131.78171
11. Jungmann, Manuela et al. “Effects of Cold Stimulation on Cardiac-Vagal Activation in Healthy Participants: Randomized Controlled Trial.” JMIR formative research vol. 2,2 e10257. 9 Oct. 2018, doi:10.2196/10257
12. Bernardi, L et al. “Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study.” BMJ (Clinical research ed.) vol. 323,7327 (2001): 1446-9. doi:10.1136/bmj.323.7327.1446