Some send sensory information, including details about smells, sights, tastes, and sounds, to the brain. These nerves have sensory functions. Other cranial nerves control the movement of various muscles and the function of certain glands. These are known as motor functions. While some cranial nerves have either sensory or motor functions, others have both. The vagus nerve is such a nerve.
The vagus nerve is a mixed nerve, which contains both sensory nerves, about 80%, which are nerves that receive sensory information from the body and send signals back to the central nervous system, and motor nerves, about 20%, eliciting actions, based on the information, to the organs it supplies nerves to. Gut reactions, like ‘butterflies in the stomach’ can be attributed to activation of the vagus nerve.
The vagus nerve also oversees the sympathetic and parasympathetic nervous systems, sending messages of anxiety or calm to the brain. As a result, it is referred to as the “nerve of compassion,” as when it is toned, it sends feelings of warmth, love, and gratitude.
It gets its name from the Latin word “wandering”, meaning it literally wanders around the body attaching to the main organs, beginning at the base of the brain, dividing into two, it travels behind each ear, over the mastoid bone (the bone just behind the ear) and runs across the chest and down into the abdomen, with connections to the larynx, trachea, bronchi, lungs, heart, liver, gallbladder, stomach, pancreas, kidneys, reproductive organs, and small and large intestines.
The vagus nerve oversees a lot of crucial subconscious bodily functions, including heart rate, digestive function, immune response, and control of mood, as well as vasomotor activity (constriction or dilation of blood vessels), and certain reflex actions, such as coughing, sneezing, swallowing and vomiting.
The vagus nerve has also been shown to be involved in social engagement by allowing us to pick up on, or sense, other people’s emotional cues.
STRESS AND THE VAGAL NERVE
Stress is a common factor to be explored and supported by anyone who is suffering from chronic illness. The stress response also known as the “fight, flight or freeze” response is activated anytime that we feel threatened, physically, mentally, or emotionally.
When we encounter stress, our body releases stress hormones like adrenaline and cortisol, designed to support the body as an acute response to enable us to fight, flee or freeze, in any moment. This response is an adaptive safety response, designed to keep us safe when threatened, but when chronically activated, stress hormones can contribute to a variety of health problems such as digestive issues, chronic pain, anxiety, depression, and many more.
Supporting the vagus nerve can help to counteract, or balance, the stress response enabling the body to rebalance and recover from the stressful encounter.
When the stress response is chronically activated, it can lead to low vagal tone, just like a muscle, the vagus nerve needs to be activated to maintain tone, so when a body has low vagal tone, the body then has a lower resilience to stress.
LOW VAGAL TONE
Low vagal tone can be linked to symptoms and conditions such as gastroparesis (food slow to pass through stomach - bloating and feeling full) small intestinal bacterial overgrowth (SIBO), irritable bowel syndrome (IBS), weight gain, mood disorders, anxiety, panic attacks, tinnitus, depression, slowed heart rate, palpitations, seizures, difficulty swallowing and fainting, among others.
Low vagal tone can also be associated with chronic inflammation because the vagus nerve plays a key role in the inflammatory response and immune system support. Vagal tone can be measured objectively by measuring heart rate variability (HRV), which is a measure of the time between each heartbeat, the more variable the time between each heartbeat is, the higher the HRV and the more resilient a body is. The lower the heart rate variability the lower the body’s resilience to stress and the less adaptive a body is to stress, so an individual may feel they have low resilience to stressful situations, both emotionally and physically.
WHAT CAUSES LOW VAGAL TONE?
As mentioned, chronic stress, which can either be psychological or emotional from stress or trauma, or physical, such as bodily injuries, like accidents, traumatic brain injuries, operations, neck and back injuries and even poor posture can contribute to low vagal tone.
Other factors include poor gut health, which could be as a result of infections, intestinal permeability, bacteria, viral and parasitic infections. Environmental toxins such as mould, heavy metals and environmental chemicals and toxins can also affect the vagal nerve. As can a diet consisting of low nutrient dense, highly processed, high sugar dietary foods, and poor sleep.
BENEFITS OF SUPPORTING THE VAGUS NERVE
Supporting the vagus nerve can help to counteract, or balance, the stress response, because the vagus nerve, when activated, activates states of rest, digest and repair.
Working with the body and working with the vagus nerve in practice can support vagal tone, supporting the body towards finding balance and towards recovery and optimal health.
This can be done in various ways, which can include the following:
Vagus nerve stimulation (VNS) devices
VNS devices, also known as TENS machines, are devices that can be applied to the skin and the device stimulates the vagus nerve transcutaneously (through the skin). Stimulating the vagus nerve can help to build vagal tone, helping the body to spend time in the parasympathetic rest, digest and detoxify state to support recovery.
Dietary and supplement interventions
Ensuring a whole food nutrient dense dietary intake to support inflammatory levels and support the anti-inflammatory dietary intake and supplementation such as omega 3 fatty acids, probiotics, and beetroot juice have all been shown to have a supportive role.
Practicing deep or belly breathing, so ensuring that you expand your belly and diaphragm when you breathe, as opposed to shallow chest breathing.
Positive social connections
Laughter (even forced belly laughter), and the true smile of happiness (Duchenne smile) have been shown to have a positive benefit on vagal tone and stress resilience. So, optimise spending time with those around you who make you laugh and smile.
Meditation is a great way to improve vagal tone. Also singing, humming or OM chanting can also stimulate the vagus nerve at the back of the throat, together with gargling or using a tongue depressor to stimulate the gag reflex.
Ice baths, or a cold shower on the back of your neck can be another way to improve vagal tone. This could be introduced by incorporating a short burst of cold water at the end of your shower, alternated with warm water, to build up tolerance.
When it comes to recovery from any illness or symptoms, whether acute or chronic, its important to consider your stress response and how that has contributed to your health status. By supporting your vagus nerve and vagal tone you can send messages to your body that it’s safe, and that it’s time to relax and de-stress, to enable it to carry out all the necessary functions of optimal digestion, detoxification, growth and repair, which are all crucial when supporting a body to rebalance and return to optimal health.