What Is The Vagus Nerve?

The vagus nerve is a cranial nerve that carries sensory information and efferent signals to many muscles, glands, and internal organs, including the heart and GI tract. It extends from the brain stem, through the neck and thorax, and down into the abdomen. It is the main contributor to the parasympathetic nervous system and a primary communication pathway between the brain and the body. Because of this relationship, the vagus nerve plays a large role in our mood, immune system, stress response, cardiovascular function, and digestion. The body is extremely responsive and reactive to all stimuli, both internal and external. When something is happening within the body that the brain needs to respond to, the vagus nerve is the primary messenger. Communicating those responses happens in milliseconds, but where are those signals coming from?

Approximately 80% of the body’s signals are sent from the body’s organ systems to the brain (afferent signals), while only 20% of the body’s signals are sent from the brain to our organ systems (efferent signals). The vagus nerve is primarily responsible for this communication.

Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders

The Importance of Vagus Nerve Communication

The vagus nerve connects multiple organ systems with the brain, and its primary function is to deliver afferent signals to the brain from other parts of the body, including the gut, heart, liver, and lungs. And because such a large portion of our immune system resides in our gut, the vagus nerve has a direct influence on our immune health. When an imbalance occurs in these organs, a message is relayed almost immediately to the brain, where measures are taken to accommodate the imbalance. The gut is a major interface between our internal environment and the outside world, thus making it a particularly important sensory organ. Imagine how you feel when you experience alarm, fear, pain, “gut-wrenching” trauma or visuals, grief, and heartbreak? All of these are deeply emotional – sensory – experiences that almost all of us feel in our gut, or our lungs and throat, or in our hearts.

When the body experiences this kind of stress, it overstimulates the vagus nerve, leading to a cascade of alarming afferent messages to the brain. Many researchers attribute the effects experienced during trauma at any stage of life (particularly adolescence) to dysfunction within vagus nerve tone, including chronic digestive imbalance, high anxiety and PTSD, migraines, sleep disorders, and autoimmune conditions.

The vagus nerve also maintains our homeostatic inflammatory response and regulates our ability to relax (remember: “rest and digest”). The belief that our state of mind and body is directly related to our emotional resilience is incredibly important when observing the function of the vagus nerve.

Signs of Vagus Nerve Damage

The vagus nerve has been linked to major depression, PTSD, inflammatory GI disorders including ulcerative colitis and Crohn’s disease, and severe anxiety. When the vagus nerve is overstimulated, or chronically weakened, there are several signs that may lead your naturopathic doctor to suspect this is an area that needs holistic support. These symptoms can include:

• A weakened immune system
• An existing autoimmune condition, including arthritis
• Mood disorders
• Chronic pain or inflammation
• Irregular heart rate
• Difficulty speaking, swallowing, and loss of gag reflex
• Anxiety, or inability to relax and feel “safe”
• Issues with digestion

Healing the Vagus Nerve

The “tone” of the vagus nerve is extremely important, and can actually be strengthened through mindfulness practices like breathwork and meditation. For the treatments of systemic inflammatory disorders and for PTSD, the research on vagal tone is promising and focuses on specific practices: “…The vagal tone is correlated with the capacity to regulate stress responses and can be influenced by breathing, its increase through meditation and yoga likely contribute to resilience and the mitigation of mood and anxiety symptoms”. These gentle practices can be enjoyed in your own home, in your car, while at work, and even together in community.

Gently stimulating the vagus nerve can be extremely therapeutic. Stimulation has an immediate calming effect on an overstimulated nervous system and overall inflammatory response. This can be achieved through diaphragmatic breathing: take a long, slow inhale, hold it slightly, and then release the breath completely. Other helpful practices to increasing vagal tone include abdominal massage, singing or vocal expression, writing, laughter, acupuncture, consistent massages, craniosacral therapy, and therapeutic exercise such as swimming, yoga, walking, and gentle resistance training. Of course, mental health counseling is just as important as any physical practice for healing past trauma.

The health of your vagus nerve is directly reflected in the health of your immune system, cardiovascular system, digestive system, and even the respiratory system. As is always the case in a naturopathic approach to healing – everything is all connected. If you need support in any of these areas, consider scheduling an appointment with one of our naturopathic doctors here at Richmond Natural Medicine.

References

Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders
Anti-inflammatory properties of the vagus nerve: Potential therapeutic implications of vagus nerve stimulation.
Reducing inflammation starts with the vagus nerve
The vagus nerve and inflammatory reflex: Linking Immunity and Metabolism
How positive emotions build physical health: Perceived positive social connections account for the upward spiral between positive emotions and vagal tone.