The Vagus Nerve: A Key Player in Your Health and Well-Being

Your body is the coolest thing you will ever own. Your body is also a complex and intricately connected system, with your brain and nervous system playing a central role in regulating its various functions. Among the many nerves that make up this system, the vagus nerve stands out for its profound influence on physical and mental health. Often referred to as the "wandering nerve" because of its extensive reach throughout the body, this article explores the anatomy of the vagus nerve, and its role and impact on your overall health.

Anatomy and Function of the Vagus Nerve

The vagus nerve, or more specifically, the tenth cranial nerve, originates in your brainstem, within the medulla oblongata, and extends downward through your neck and into your chest and abdomen. The nerve branches out to multiple organs, including your heart, lungs, liver, spleen, stomach, intestines, and kidneys. It is a critical component of your autonomic nervous system (ANS) which regulates involuntary physiologic processes like heart rate, blood pressure, and respiration.

Your ANS has two parts. The sympathetic nervous system (SNS) which owns the "fight or flight" response that prepares your body to respond to perceived threats by increasing heart rate, redirecting blood flow to muscles, and releasing stress hormones. The parasympathetic nervous system (PNS) is associated with the "rest and digest" response, and helps your body return to a state of calm after a stressful event. The vagus nerve plays a major role in promoting relaxation, digestion, and recovery.

Vagal Tone and Your Physical Health

The impact of the vagus nerve on various bodily functions has been the subject of extensive research, leading to a better understanding of how vagal tone— a measure of vagus nerve activity—can affect you physically in these key areas:

• Cardiovascular health: The vagus nerve helps to regulate heart rate and blood pressure. High vagal tone is associated with a lower resting heart rate, reduced blood pressure, and increased heart rate variability (HRV), which is the variation in time between heartbeats. HRV is a key indicator of autonomic nervous system balance and cardiovascular health.
• Digestive health: The vagus nerve is essential for proper digestive function, as it regulates the release of digestive enzymes, gastric acid, and bile. It also controls the contractions of the stomach and intestines, which move food through the digestive tract. Impaired vagal function can lead to various gastrointestinal issues, including acid reflux, gastroparesis (delayed stomach emptying), and irritable bowel syndrome (IBS).
• Immune System Regulation: The vagus nerve's role in modulating inflammation is a crucial aspect of its impact on your physical health. Chronic inflammation is a common underlying factor in many diseases, including autoimmune disorders, metabolic syndrome, and neurodegenerative conditions like Alzheimer's disease. By regulating the production of pro-inflammatory cytokines, the vagus nerve helps prevent excessive inflammation and supports your body's ability to fight off infections and heal from injuries.

Vagal Tone and Your Mental Health

The influence of the vagus nerve and its connection to the brain, particularly through the gut-brain axis, plays a significant role in mood regulation, stress response, and cognitive function. Vagal tone plays a role in your mental health specifically around:

• Stress and Anxiety: High vagal tone is associated with a greater ability to recover from stress, as it promotes the activation of the PNS. This helps reduce the physiological symptoms of stress, such as increased heart rate and muscle tension, and promotes a state of relaxation.

  Conversely, low vagal tone is associated with heightened stress reactivity, a reduced ability to cope with stress, as well as with chronic stress. Enhancing vagal tone through practices such as deep breathing, meditation, and yoga can help improve stress resilience and reduce anxiety.

• Depression: Low vagal tone has been linked to an increased risk of depression, as it is associated with reduced PNS activity and increased SNS dominance. This imbalance can contribute to the physiological symptoms of depression, such as fatigue, sleep disturbances, and gastrointestinal issues.
• Cognitive Function: The vagus nerve's influence on cognitive function is an emerging area of research related to cognitive processes like attention, memory, and executive function. High vagal tone has been linked to better cognitive performance, particularly in tasks that require self-regulation and decision-making.

Can You Enhance Your Vagal Tone?

Given the importance of the vagus nerve in your overall health and well-being, strategies to enhance vagal tone have gained attention, as have potential therapeutic interventions. Currently, there are two pathways to promote vagal nerve tone, the non-medical and the medical.

The non-medical pathway includes:

• Deep breathing, specifically diaphragmatic or belly breathing, which activates the vagus nerve and promotes relaxation. Try 4-7-8 breathing; inhale through your nose for four counts, hold your breath for seven counts and exhale through your nose for eight counts. This breathing technique is highly effective in promoting sleep and should not be done while driving or engaging in another activity where your keen attention is required.
• Meditation and mindfulness practices that encourage present-moment awareness which can stimulate the vagus nerve. To practice meditation, try a five minute session where you are seated in a quiet area with your eyes closed. Concentrate on your breath as you refrain from paying attention to other concerns.
• Regular physical activity, especially aerobic exercise, has been shown to increase vagal tone. Exercise also promotes cardiovascular health and helps regulate the stress response. To practice, follow the CDC’s recommendations for 150 minutes per week of moderate exercise along with 2-3 sessions of strength training. Talk a brisk walk, cycle or dance. Or spend some time in the gym for a strength-training session.
• Brief exposure to cold, such as taking cold showers or splashing cold water on the face, can stimulate the vagus nerve by activating the PNS. Read this MGH article on cold plunges for other ideas.
• Finding social connection through practices like expressing gratitude, engaging in acts of kindness, and fostering meaningful social connections. These all support vagus nerve function.

The medical pathway relies on vagus nerve stimulation (VNS), where a device that delivers electrical impulses to the vagus nerve is implanted in two places near the left side of your collarbone. A VNS device can help to regulate mood and improve depressive symptoms. VNS devices have been approved for treatment-resistant depression, particularly in cases where traditional antidepressant medications and therapies have not been effective. Research is ongoing to determine if VNS devices can be used to treat multiple sclerosis, migraine, and Alzheimer’s disease as well.

The Vagus Nerve Reset: Fact and Fiction

The vagus nerve has become a topic of great interest on social media and in the press. And strategies for ‘resetting’ this nerve abound, including two that are especially popular.

Hands-on massage therapy on specific points in the neck and ears has been touted as a vagus nerve reset. While most massage will feel good to most people and supports general relaxation, attempts to directly stimulate the vagus nerve through strong or prolonged physical pressure or even the use of tools can have the opposite effect.

Omega 3 fatty acid supplementation and the use of probiotics have been described as vagus nerve stimulators. While there are circumstances where these supplements are warranted as part of a healthy diet, there is no research that points to them as having a specific or measurable impact on the function or tone of the vagus nerve.

The vagus nerve is a critical component of your nervous system, with far-reaching effects on both physical and mental health. Its role in regulating heart rate, digestion, inflammation, and mood makes it a key player in maintaining overall well-being. By understanding the importance of the vagus nerve and exploring strategies to enhance its function, you can take simple, proactive steps to support your health and improve your quality of life.