By
Melbourne Functional Medicine
Jabe Brown
Medically reviewed by:
The Vagus Nerve is perhaps one of the most significant yet underappreciated contributors to health and wellbeing. In fact, there’s a chance you might not have even heard of it before.
While other issues like reproductive health, gut health and thyroid health receive a lot of attention, the vagus nerve is rarely talked about outside health and wellness circles. Which is surprising, given we use it every day!
The vagus nerve plays an important role as the body’s communication highway, carrying information back and forth between the brain and internal organs.
In this article, we’ll explain more about the vagus nerve, what it does, and how to optimise its function for better health.
The vagus nerve, also known as the tenth cranial nerve, is actually a set of nerves connecting most of the major organs between the brain and the gastrointestinal tract.
It’s the longest and most complex of the 12 cranial nerves and extends from the brainstem through the neck and thoracic region down to the abdomen. This extensive branching is how the nerve got its name, as vagus means ‘wanderer’ in Latin.
The vagus nerve acts as a two-way communication pathway between the brain and gastrointestinal tract, transmitting an array of messages between the digestive system, organs and the brain. It’s been described as the mind-body connection, and an integral component of the “gut-brain axis” (GBA).
This extensive network of nerves provides the central nervous system with integral information about the function of internal organs, particularly the gut, liver, heart and lungs. It’s therefore responsible for the modulation of our:
With innervations (the supply of nervous system tissue) in both the cognitive and emotional centres of the brain, the vagus nerve also plays a key role in:
The vagus nerve is a primary driver of the parasympathetic nervous system, responsible for “rest-and-digest” functions, and works as a counterbalance to the sympathetic nervous system, which regulates our “flight-and-fight” response.
As a result, the vagus nerve is responsible for activating that sense of calm you feel when you’re snuggled safely in the arms of a loved one, and the intuitive ‘gut feeling’ you have when something, or someone, seems not quite right.
Its role as a multi-directional messenger is so critical to our everyday function that we simply couldn’t live without it. And while some cranial nerves have either sensory or motor functions, the vagal nerve has both.
Sensory functions of the vagus nerve include:
Motor functions of the vagus nerve include:
We can also look at the functions of the vagus nerve based on the location of its branches throughout the body.
Vagal tone is a measure of your vagus nerve activity, and it’s often used as an indicator of physical health. Individuals with higher vagal tone tend to be able to regulate bodily functions more readily, including their heart rate, blood sugar, and emotions.
Low vagal tone, on the other hand, has been associated with poor emotional and attentional regulation and is considered a marker of sensitivity to stress. Low vagal nerve activity is also linked to high inflammation, digestive issues, and cardiovascular disease.
Research published in Psychological Science in 2013 revealed this link between high vagal tone, physical health and emotional health.
Essentially, researchers found that individuals who experienced more positive emotions and social connectedness had a higher vagal tone. It appears to work in reverse too. Improvements in vagal tone can increase your perception of social connectedness.
The symptoms of an underactive vagus nerve, a.k.a low vagal tone, are common and can occur for a variety of reasons. Low vagal tone is often associated with symptoms such as:
The vagus nerve, like any other nerve in the body, can be damaged through physical trauma, surgery or disease, such as diabetes. Damage to the vagus nerve my result in more defined conditions:
Gastroparesis: Also known as delayed gastric emptying, gastroparesis is a partial paralysis of the stomach. It can occur when a damaged vagus nerve is unable to send effective signals to the gastrointestinal system. As a result, food remains in the stomach longer, rather than moving into the small intestine to be digested. Symptoms include:
Vasovagal syncope: An overactive vagus nerve can cause a sudden drop in blood pressure and fainting in response to stress triggers, such as exposure to heat, fear of bodily harm, the sight of blood or needles, straining, and standing for long periods of time.
Low vagal tone can arise for a number of different reasons. Some of the factors that contribute to vagal tone are:
Psychological: From a psychological perspective, vagus nerve function can be impaired through traumatic experiences. Unresolved trauma and even low-grade chronic stress can manifest physically as low vagal tone.
Physiological: Damage to the vagus nerve from physical trauma, surgery or diseases such as diabetes can also cause symptoms throughout the digestive and cardiovascular system. Depending on the site of damage, this could result in speech difficulties, a hoarse or wheezy voice, trouble swallowing liquids, ear pain or loss of gag reflex. It could also manifest as rapid heart rate, abnormal blood pressure, nausea, vomiting, abdominal pain or bloating.
The good news is that just like a muscle, vagal tone can be strengthened through regular stimulation. Healthy and strong vagal tone results in:
Research is also discovering new ways vagal stimulation could be used in the treatment of multiple sclerosis, Alzheimer’s disease, and cluster headache.
Devices are currently used in conventional medicine to stimulate the vagus nerve through direct electrical impulses, and address a range of conditions connected to vagus nerve damage. However, there are also ways to stimulate the vagus nerve and improve vagal tone naturally.
Here at Melbourne Functional Medicine, our practitioners can help you identify the contributing factors of your vagus nerve dysfunction, and work with you to strengthen vagal tone. Here are just some of the methods you can use:
Posture: Poor posture can compress the vagus nerve, disrupting signals between the body and brain. A forward head posture and rounding of the shoulders have become common problems with the increasing time people spend seated and using computers. Breastfeeding can also contribute to poor posture and a rounded upper back. Our practitioners may recommend the SD Posture Correction Device, which can release pressure on the vagus nerve, or lying down and placing a foam roller in between the shoulder blades to improve posture.
Manipulation: Just like joints and ligaments, our nerves can benefit from physical manipulation too. Chiropractic adjustments have been found to improve heart rate variability by boosting the function of the vagus nerve, while massage has even been attributed to a reduction of seizures through vagal stimulation.
Nutrition: Both whole foods and supplements can improve the efficiency of the vagus nerve. Nerves are covered in a myelin sheath, which is a fatty covering that protects and insulates the nerve fibres. Some of the key nutrients that support a healthy myelin sheath are Omega 3, specifically DHA, and Vitamin B12.
Vibration: Humming, singing, gargling and breathwork (like the 4-7-8 exercise) are all vagal stimulation practices which create vibrations of the vagus nerve. Research has found chatting ‘OM’ in meditation or yoga to be just as effective at calming the vagus nerve as some conventional vagus nerve therapy options used in depression and epilepsy.
Bitters: Bitter tasting herbs, known commonly as bitters, have been found to stimulate the vagus nerve and improve vagal tone by sending stimuli to the brain. Herbs like gentian, wormwood and dandelion, as well as more common table variety herbs like rocket and radicchio can all have a stimulating effect on the vagal pathway.
Cold exposure: By now you’ve probably heard of the Wim Hof Method. It combines breathwork with submersion into freezing water, and claims to improve everything from immune health and digestion to greater focus, energy levels and emotional wellbeing. You can also stimulate the vagus nerve with a cold shower, cold foods or a swim in cold water.
This is just a small selection of the ways in which your healthcare team can help you find the best solution and treatment options for a healthy vagus nerve.
Speak with your practitioner in your next session to find out the best approach for you.
