Understanding the Vagus Nerve: Anatomy and Basics

Looking up from a canyon at the night sky

In today’s digital world, we can communicate with others in an instant. Need to ask your mom about her baked salmon recipe? Want to disrupt your friend’s work day with a dad joke? How about wishing your cousin a happy birthday? All of this can be done in a flash and from a distance with a simple text message. 

But such speedy communication doesn’t just exist outside of our bodies. The vagus nerve—a sensory network that tells the brain what’s up with the body’s organs—leverages its own communication superhighway.

What messages are being sent along the vagus nerve and how does its function affect your brain and body? In this guide, we’re exploring everything you need to know about the vagus nerve, including its anatomy, functions, vagus nerve activity, and importance in medical science. 

Vagus nerve 101

So, what is the vagus nerve?

Put simply, it's the main cranial nerve that sends information from your brain to your vital organs and back again. In doing so, the vagus nerve plays a critical role in the parasympathetic nervous system (PNS), which is responsible for regulating your: 

  • Heart rate
  • Breathing
  • Digestion

An easy way to think about and remember the vagus nerve’s functions is “rest and digest.”

Interesting, the vagus nerve gets its name from the Latin word for wandering—and it certainly gets about. In fact, of all your cranial nerves, the vagus nerve is the lengthiest. 

Where is the vagus nerve exactly?

It’d be quicker to list the places it isn’t. This is because the vagus nerve runs from your brain to your abdomen, connecting with vital organs along the way. It resembles a slender, branching thread that weaves its way throughout the body. 

Although its incredible journey originates in your brainstem, the nerve itself also passes through your:

  • Neck
  • Chest
  • Heart
  • Lungs
  • Abdomen
  • Digestive tract

Vagus nerve anatomy

The fibers of the vagus nerve pack 200,000 sensory nerve cells — 100,000 on each side. In fact, there are actually two vagus nerves that run symmetrically on either side of the body for a balanced network of connections. However, we refer to them as one because they work in unison, and their responsibilities for maintaining the body’s homeostasis largely overlap.

When it comes to the anatomy of your vagus nerves, there are three key characteristics to note:

  • They branch off – The vagus nerve splits into branches to reach different parts of your body. These branches then convene at a trunk.
  • They intertwine – Several branches intertwine with the digestive system to help us process our meals.
  • They supply different areas – Some branches liaise with the heart to regulate our heartbeat, while others work with the lungs, aiding our breathing. 

Now, let’s explore how the vagus nerve interacts with our nervous system.

Role of the vagus nerve in the nervous system

The vagus nerve is a critical component of the parasympathetic nervous system. As mentioned earlier, this system is responsible for regulating heart rate, deep breathing, and digestion.

In fact, the PNS works in opposition to your sympathetic nervous system (SNS), which handles your fight or flight response. However, both systems trigger involuntary responses. 

Your sympathetic nervous system causes increases in: 

  • Alertness
  • Energy
  • Heart rate
  • Breathing rate
  • Blood pressure

Meanwhile, your parasympathetic arm conserves energy, keeps you relaxed, and stimulates digestion. To that end, you can’t have a conversation about the PNS without discussing the vagus nerve. 

Here’s how it operates within your nervous system:

  • Parasympathetic regulation – The vagus nerve is at the helm of your PNS. It sends frequent and mild electrical impulses to regulate internal organ functions.
  • Brain-body communication – The vagus nerve enables rapid messaging between the brain and internal organs. Studies of the vagus nerve have suggested that your organs are key sources of sensory information for your brain.
  • Stress response – The vagus nerve adapts to and regulates anxiety and stress-induced changes. Its influence on your stress response is key for mental health.
  • Inflammatory control – The vagus nerve uses anti-inflammatory substances to protect against chronic conditions. As part of its relaxation response, it releases the neurotransmitter acetylcholine, which positively affects inflammation in your body.
  • Gut-brain axis facilitation – The vagus nerve transmits vital information between the gut and the brain. This connection is foundational in understanding the interplay between digestive processes and emotional well-being.

In essence, the vagus nerve helps keep your internal systems in tune and balanced, and this balancing act is critical to your physical and mental health. 

To further understand its importance, let’s take a look at the vagus nerve’s significance for your survival and well-being.

How vagus nerve functions impact our survival and well-being

We can file the vagus nerve’s functions into four primary categories:

  • Sensory – The vagus nerve collects information about pressure and chemical changes from your body’s organs. The intel helps regulate your bodily functions in real time, so that they’re all in sync.
  • Special sensory – The vagus nerve comes into play as you eat, adding the taste sensation at the back of the tongue and throat.
  • Motor – The vagus nerve also sends signals to the muscles in your organs, controlling actions like swallowing, speaking, and keeping your heart rate steady.
  • Parasympathetic – The vagus nerve maintains your body’s equilibrium. It governs the regulation of heart rate and digestion, conserves energy, and responds appropriately to rest.

So, how do these functions impact your day-to-day life?

Ultimately, the vagus nerve helps:

  • Manage your emotions – When you feel a rush of calm after a stressful moment, you can thank the vagus nerve for regulating your mood. It works to keep stress and anxiety at bay by subtly influencing your heart rate and deep breathing to maintain emotional balance.
  • Taste and digest food – Why does putting away a hefty meal feel so satisfying? When the vagus nerve activates, it releases feel-good hormones associated with eating. Functionally, the vagus nerve keeps food moving smoothly through your digestive tract, helping you soak in nutrients—all critical for a well-functioning gut.
  • Control your breathing – When you’re relaxed, your breathing is typically slow, and your heart isn’t racing. That’s the vagus nerve subtly controlling the rhythm and pace of your heartbeat. It sends signals to keep things steady and balanced so that your heart maintains optimal function, whether you’re at rest or on the go.
  • Strengthen your immune responses – Have you ever wondered why some people bounce back quickly from a cold? It’s thanks in part to the vagus nerve which helps to manage inflammation and control immune responses. Because you need inflammation to heal and protect your body, the vagus nerve contributes to overall health, helping you fend off threats and recover from illnesses.

Now that we’ve uncovered the vagus nerve's everyday impacts, let’s discuss why it's a focal point in medical science.

Clinical relevance of the vagus nerve

What is vagus nerve research so useful for?

Studying the vagus nerve has empowered doctors and medical professionals to treat an incredible range of patient problems. The nerve’s transformative implications have made it a linchpin in pioneering clinical practices, some of which include:

  • Therapeutic interventions – The vagus nerve’s intricate functions are guiding researchers in developing innovative therapies. Focusing on personalized vagus nerve stimulation (VNS), these VNS therapy approaches are especially relevant for those grappling with treatment-resistant depression and anxiety. Vagus nerve stimulation (VNS) therapy has carved a new avenue for tackling deeply troubling issues.
  • Biofeedback potential – The vagus nerve’s intricate communicative nature is a gateway to advanced biofeedback therapies. By tapping into the vagus nerve’s signals, biofeedback therapies could enhance your ability to manage stress, control bodily reactions, and mitigate various health issues. Such vagus nerve activity developments could redefine the boundaries of self-regulation and healing.
  • Surgical innovation – The vagus nerve is being manipulated by medical professionals in surgeries to address a spectrum of gastrointestinal disorders. Techniques exploring vagal nerve stimulation and modulation and targeted interventions offer hope for those enduring chronic conditions. Converging this knowledge and innovation could bridge surgical precision with individualized treatment.
  • Neurological research – The vagus nerve is the subject of extensive research in neurology. Researchers are keen on exploring how vagal nerve stimulation and tweaking its signals can unlock new understanding and solutions for neurological disorders and vagus nerve dysfunction. From mitigating the impacts of epilepsy to exploring connections with Alzheimer’s, the vagus nerve is teetering on the edge of one breakthrough after another.
  • Immunomodulation – The vagus nerve’s capacity to influence immune responses makes it a hotbed of research in immunology. Scientists are exploring ways to modulate immune responses by manipulating the nerve’s signaling. Modulating its activity is on the horizon of revolutionizing treatments for various autoimmune diseases like rheumatoid arthritis.
  • Wellness and prevention – The vagus nerve is proving useful in advancing wellness practices and preventive healthcare. We can optimize immune balance and diminish inflammation through natural techniques to pave the way for a healthier life. Practical approaches like self-abdominal massage demonstrate how stimulating the vagus nerve can help maintain health and ward off potential ailments. The field is rapidly evolving in ways to leverage the vagus nerve for holistic wellness.

The vagus nerve's clinical relevance is compelling—the treatments derived from vagus nerve studies show immense promise for many patients’ day-to-day well-being.

Assist your vagus nerve in calming your body and mind with Apollo

In exploring the vagus nerve, the Apollo wearable shows big opportunities for health advancements in its ability to improve vagal tone.

As we uncover its potential in various fields, we find a parallel in the Apollo wearable — a device designed to support your bodily rhythms and create a balanced, harmonious state of being.

With our science-backed tech, past real-world and clinical trials have shown people consistently using Apollo get 40% less stress (on average), an 11% increase in HRV (on average), up to 25% more focus, and up to 19% more time in deep sleep.
Stress less and sleep more with the Apollo wearable.


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National Library of Medicine. Neuroanatomy, Parasympathetic Nervous System.

WebMD. Vagus Nerve: What to Know.

National Library of Medicine. Vagus Nerve as Modulator of the Brain–Gut Axis in Psychiatric and Inflammatory Disorders.

ScienceDirect. The Vagus Nerve in Appetite Regulation, Mood, and Intestinal Inflammation.

Frontiers. Critical Review of Transcutaneous Vagus Nerve Stimulation: Challenges for Translation to Clinical Practice.