vagus, schmagus!
The Vagus Nerve: the One Nerve to Rule them All
Welcome to the first deep dive on the Waning Crescent blog! Today we're talking about one of my absolute favorite topics: the vagus nerve. This wandering wonder is the longest cranial nerve in your body, and understanding how it works is like getting the cheat codes to your own nervous system.
If you've ever felt your shoulders drop during a long exhale, experienced that blissful post-massage glow, or noticed your anxiety melt away after humming along to your favorite song—you can thank your vagus nerve. Let's get nerdy about why this matters, what's actually happening in your body, and how you can work with this system (especially through bodywork and self-care practices) to feel more grounded, safe, and regulated.
What Even IS the Vagus Nerve?
The vagus nerve (Latin for "wandering") is cranial nerve X, and boy, does it wander. This nerve originates in your brainstem and extends through your neck, chest, and abdomen, branching out to your heart, lungs, digestive tract, and more. It's the main component of your parasympathetic nervous system—the part responsible for "rest and digest" functions.
Here's something wild: the vagus nerve is about 80% sensory (afferent) fibers and only 20% motor (efferent) fibers. This means it's primarily sending information from your organs to your brain, constantly updating headquarters about what's happening in your body. Your gut, heart, and lungs aren't just passive receivers of brain commands—they're major sources of sensory information that shapes how you feel and respond to the world.
The vagus nerve handles an astonishing array of functions:
Heart rate regulation: It acts like a brake pedal for your heart, slowing things down when you're safe
Digestive function: It controls the muscle contractions that move food through your GI tract and triggers the release of digestive enzymes
Breathing coordination: It monitors and influences respiratory patterns
Inflammation control: Through something called the "cholinergic anti-inflammatory pathway," it helps keep inflammation in check
Voice and swallowing: It innervates muscles in your throat and voice box
Emotional regulation: It influences mood and stress responses through its connections to the brain
Enter Polyvagal Theory: The Three-Lane Highway
Here's where it gets really interesting. Traditional understanding divided the autonomic nervous system into two parts: sympathetic (fight/flight) and parasympathetic (rest/digest). Before the 1990s, the nervous system was thought of as a binary system—stress response either on or off, stressed or not stressed.
But in 1994, neuroscientist and psychologist Stephen Porges introduced Polyvagal Theory, which shattered this dualistic view. Porges conducted extensive neurophysiological research, measuring responses like heart rate variability to various stimuli and stressors, and integrated clinical observations of individuals with different responses to stress and trauma. What he discovered was revolutionary: humans possess varied stress and nervous system activation states—a spectrum of responses, each with its degree of activation within the autonomic nervous system.
Polyvagal theory proposes a hierarchical organization of autonomic states mediated by the vagus nerve, emphasizing the unique role of the ventral vagal complex in facilitating social behavior and physiological flexibility. The core research model centers on the concept of the "vagal brake"—a moderating factor that maintains homeostasis, acting as early as infancy.
Think of it like this: you have three circuits that respond to the world around you…
1. Ventral Vagal (The Social Engagement System)
This is the newest evolutionary circuit, found in mammals. The anterior vagus functions as an active "vagal brake"—it can rapidly inhibit or disinhibit vagal tone to mobilize or calm you. When this system is online, you feel safe, connected, and able to engage socially. Your face is expressive, your voice has prosody (melodic quality), and you can regulate your internal state while staying present with others. This is the yummy place we all want to be, and where massage seeks to bring us.
2. Sympathetic (The Mobilization System)
This is your action system—fight or flight. When the ventral vagal brake releases, sympathetic activation kicks in to help you move, defend yourself, or get things done. This isn't bad; it's adaptive! The problem comes when we get stuck here chronically (more on that later).
3. Dorsal Vagal (The Shutdown System)
This is the most primitive component in the evolution of this system, dependent on the dorsal, posterior branch of the vagus shared with most vertebrates. When the nervous system perceives a life-threatening situation with no escape, this circuit activates—freeze, collapse, dissociation. Think playing dead, conservation of energy, numbing out.
The key concept here is neuroception: the neural evaluation of risk and safety that reflexively triggers shifts in autonomic states without requiring conscious awareness. Your nervous system is constantly scanning for cues of safety or danger, and it responds accordingly—often before your conscious mind catches up.
The Body Remembers: Peter Levine's Somatic Perspective
While Porges was mapping the vagus nerve's role in our stress responses, psychologist Peter Levine was asking a different question: why do animals in the wild, who are constantly under threat of predation, rarely show symptoms of trauma—while humans often get stuck in traumatic stress for years or decades?
What Levine discovered became the foundation of Somatic Experiencing, his body-oriented approach to healing trauma. He observed that when prey animals escape a predator, they inevitably tremble and shake in the aftermath, releasing leftover fight-or-flight hormones still coursing through their system. As they "discharge" this survival energy through spontaneous gentle shaking and trembling, animals return to coherent functioning—trauma fully resolved.
Humans have lost access to this innate capacity to reset equilibrium after a threat. When fight and flight aren't options, we freeze and immobilize. If this immobility phase doesn't complete—if the massive energy prepared for fight or flight doesn't discharge—that charge stays trapped. From the body's perspective, we're still under threat, and we continue to perceive the world from that perspective. Our stress used to be from outrunning lions, and FULLY utilizing the increased heart rate, muscle tone and cortisol that comes from the sympathetic response. Now, the same processes apply, but instead of lions and bears we’ve got deadlines and construction traffic (Portland in the summer, IYKYK).
Levine emphasized that it's not the traumatic event itself that causes long-lasting trauma—it's the overwhelming trapped response to the perceived life threat that causes an imbalanced nervous system.
Here's the beautiful part: both Porges and Levine are describing the same phenomenon from different angles. Porges mapped the neural pathways and evolutionary hierarchy. Levine showed us how to work with those pathways through the body's wisdom. Together, they've given us a comprehensive understanding of how our nervous systems respond to threat and, critically, how we can help them find their way back to safety.
Self-Regulation Tools: Your Home Practice
The beautiful thing about understanding your vagus nerve is that you can actively work to improve your vagal tone—essentially, your nervous system's resilience and flexibility. Higher vagal tone predicts better self-regulation, social engagement, and physiological recovery, while reduced vagal efficiency has emerged as a sensitive marker of dysautonomia (*the topic of my next entry!*).
Here are evidence-based practices you can use:
1. Diaphragmatic Breathing
Slow, nose breathing engages the diaphragm, which is connected to the vagus nerve. Deep breathing with bigger diaphragm movements actually "massages" the heart from within.
To Try: Place one hand on your chest, one on your belly. Breathe so that only your belly hand moves. Inhale for 4 counts, exhale for 6-8 counts. The longer exhale is key. I love the O_pen app for guided breathwork meditations.
2. Cold Exposure
Exposing your body to acute cold conditions, such as taking a cold shower or splashing cold water on your face, increases stimulation of the vagus nerve. While your body adjusts to the cold, sympathetic activity declines while parasympathetic activity increases.
To Try: End your shower with 30 seconds of cold water. Hike to an alpine lake and jump in the icy cold glacier water. Even just a cool compress on the back of your neck will do the trick (but nothing beats the Sandy River!)
3. Vocalization
When you sing loudly, your vocal cords vibrate, stimulating your vagus nerve. Humming, chanting, gargling—all create vibrations that activate vagal pathways.
To Try: Hum your favorite tune for a few minutes. Or gargle with water vigorously for 30-60 seconds. Bonus points for singing loudly in the car or shower.
4. Exercise
Physical activity improves vagal tone, with both interval training and endurance training being great for activating the vagus nerve. Exercise stimulates hormonal responses that benefit brain and mental health.
To Try: Regular walks, swimming, cycling, boogie in your bedroom—whatever movement brings you joy. The key is consistency, not intensity.
5. Meditation and Mindfulness
Mind-body therapies cultivate somatic awareness combined with mindfulness-based qualities of nonjudgment, nonreactivity, and curiosity. Meditation increases vagal tone and helps you build capacity for stress as you practice in stillness the art of self-regulation.
To Try: I really believe that anything can be done with mindfulness and presence, and often find my meditative flow in dancing, yoga, making music, or laying in a hammock next to Timothy Lake. AND, there’s nothing quite like sitting still and being with yourself in quiet. Even 5-10 minutes of sitting, focusing on your breath or a mantra, makes a difference. Apps, guided meditations are great, meditating in community (Sangha) is even better.
6. Social Connection
This one's huge. The ventral vagal system is literally called the social engagement system. Our interactions with others can increase vagal tone and calm the sympathetic nervous system. Co-regulation with safe others is medicine.
To Try: Spend time with people who make you feel safe and seen. Be in community. Make eye contact. Share a meal. Have a real conversation. Snuggle your cat. Get as many hugs as possible.
7. Self-Massage
You can stimulate your own vagus nerve with simple techniques. Massage the neck, particularly along the sides where the vagus nerve runs, or massage the ears, focusing on gentle circular motions.
To Try: Gently massage your neck along the sides, from behind your ear down toward your collarbone. Use slow, gentle pressure. Listen to your body.
The Bigger Picture
Understanding the vagus nerve isn't just about collecting cool facts (though I love those too!). It's about recognizing that you have a built-in system for regulating stress, healing, and connection—and you can actively strengthen it.
Your vagus nerve is constantly listening to your internal state and your environment, making unconscious decisions about whether you're safe or in danger. When you understand this, you can become a partner in your own regulation rather than feeling at the mercy of anxiety, shutdown, or chronic stress.
For those of us working with bodies—whether our own or others'—this knowledge is foundational. We're not just relaxing muscles; we're sending safety signals, helping nervous systems find their way back to ventral vagal regulation where healing, digestion, connection, and joy can happen.
The vagus nerve is proof that our bodies are wise, adaptive, and always working toward balance. Sometimes we just need to remember how to listen—and how to help.
Want to go deeper? There's so much more to explore: the gut-brain axis, heart rate variability as a measure of vagal tone, the link between vagal function and inflammation, and how polyvagal-informed approaches are changing trauma therapy. There are several podcasts, TEDx talks and books I’d recommend!
May your vagus be toned, your breath be slow, and your nervous system be resilient.
✨ Stay well, stay curious, and stay connected. ✨
Mystic Lake at Mt. Rainier. Activating my vagus nerve. Absolutely freezing.