How does the vagus nerve influence wellness?

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One of the most vital aspects of basic bodily functions and deeper mental and physiological wellness lies in a cranial nerve that connects the brain to the major organs and body systems. While often we think about health and well-being in terms of our heart health, cognitive function, or mental wellness, we rarely think about the importance of our nervous system. In particular, one vastly reaching nerve, the vagus nerve, has much to do with our potential to function optimally.

What is the vagus nerve?

There are 12 cranial nerves. The vagus nerve is the tenth of the twelve cranial nerves and is the longest of these nerves. Originating in the part of the brainstem called the medulla, which is at the back of the brain, the vagus nerve travels from the base of the head, down the neck, through the torso all the way to the colon in the lower abdomen. In fact, its name comes from the Latin word for “wander.” The idea is that it wanders throughout the body, connecting organ systems to the brainstem.

The nervous system communicates from the brain to the body and back again. As one of the most important, the vagus nerve communicates with major organs and body systems, creating a communication link to the brain. It also directs or plays a major role in a broad range of functions and diverse activities in the body –sensory, physical, and hormonal.

What makes the vagus nerve unique?

The vagus nerve is the only cranial nerve that reaches the thoracic and digestive organs. It is an essential player in the parasympathetic nervous system, which is part of the autonomic nervous system. The parasympathetic nervous system involves the physiology of resting and digesting.

The vagus nerve has three functional pathways that include:

• Visceral efferent pathway
• Motor efferent pathway
• Afferent pathway

Efferent is motor output, meaning neurons that carry information from the central nervous system to the body’s organs, muscles, and tissues. An afferent nerve does the opposite, bringing signals from the periphery to the central nervous system. In other words, afferent refers to the sensory input coming back to the nervous system.

How does the vagus nerve influence wellness?

The vagus nerve is a major anatomical and physiological player for body functions crucial to basic life and higher-level wellness activities. The vagus nerve is crucial to homeostasis in our body systems—cardiovascular, gastrointestinal, and respiratory.

It controls involuntary body activities like heart rate, breathing, and interorgan sensory communication. It also serves functions of higher-level physiology like gut-brain communication and relaxation. This means that the vagus nerve helps with the most basic needs of living, but also aids in our health on a deeper level.

Crucial physiological functions related to the vagus nerve:

• Helps with breathing
• Controls heart rate
• Speaking
• Hearing
• Digestive tract movement
• Swallowing and gag reflex
• Blood pressure
• Bladder function
• Sensory processes – pain, touch, temperature

Respiratory function

The vagus nerve draws out a neurotransmitter acetylcholine, which tells your respiratory system to breathe. One of the ways that you can stimulate your vagus nerve is by doing slow, long, deep breathing exercises. This is also related to the ways the vagus nerve works to relax our body during times of stress.

Controls your heart rate

Acetylcholine also plays a role in slowing your heart rate. The vagus nerve carries sensory communication from the aorta via baroreceptors and chemoreceptors. The baroreceptors send information regarding blood pressure in the circulation system. Chemoreceptors provide information via the vagus nerve about oxygen levels in the blood. Because the vagus nerve is the primary nerve involved in the parasympathetic nervous system, it helps slow heart rate during or after times of stress exposure. Without a healthy vagus nerve, being able to relax after a stressful event could take much longer and therefore could expose your body to even more damaging stress hormones.

Speaking and swallowing

The vagus nerve supplies nerves to muscles in the pharynx and larynx that aid in speech and swallowing. It also plays a role in the gag reflex, which is crucial to protecting our airways from food, liquid, or foreign objects. Relaxed muscles in the throat can also help make breathing easier, which in turn helps keep the vagus nerve system healthy.

Vagal nerve contribution to deeper wellness:

• Calms the nervous system
• Plays a role in sense of taste
• Aids in communication about satiation
• Anti-inflammation
• Gut-brain connection
• Reduces stress and increases relaxation
• Contributes to memory formation
• Fertility and sexual health

Anti-inflammation

Inflammation is a normal part of the immune system’s response to injury or illness. The vagus nerve, with its vast sensory network, will notice when the body is producing substances like cytokines or other inflammatory markers, and in turn signal to the brain the need to produce anti-inflammatory neurotransmitters. This helps regulate the immune system response and helps protect against the harmful effects of chronic inflammation.

Stress reduction and relaxation

The sympathetic nervous system sends the body into the overstressed state of fight or flight, which is crucial for human survival. This system tells us when things are just not right – be it as traumatic as a truly dangerous situation or a less problematic one like a negative interaction with a coworker that makes you feel uneasy. How our bodies respond to that initially can be contributed to the calming effects of the vagus nerve.

The sympathetic nervous system releases adrenaline and cortisol, two hormones necessary for human survival. The vagus nerve, as part of the parasympathetic nervous system, in turn releases the neurotransmitter acetylcholine. It also signals other body parts to release neurotransmitters such as oxytocin and vasopressin, which also aid in calming our bodies after stressful interactions.

Gut-brain connections

The vagus nerve is the only cranial nerve with far-reaching access to the gut. This back-and-forth communication from the gut to the brain helps with satiation (the body telling the brain that it is no longer hungry).

But beyond issues of eating, it also contributes significantly to mental health associated with stress, trauma, and the body’s response. Much of the body’s neurotransmitters such as serotonin are made in the gut. Pain, healthy weight management and glucose/insulin mediation are all related to stress and mental well-being.

Summary:

• The vagus nerve is the longest and most far-reaching cranial nerve.
• It connects the brain to most of the body’s organs and functioning systems.
• It slows heart rate and regulates blood pressure.
• The vagus nerve stimulates breathing.
• It processes sensations such as touch, temperature and pain.
• The vagus nerve plays a key role in rest and digest, and even more expansively contributes to relaxation and stress reduction.