How the Vagus Nerve Works · Bedrock Nation

How the Vagus Nerve Works

How the brain talks to the immune system (and why this changes everything)

If you’ve ever noticed that stress makes your gut worse, your sleep worse, your mood shorter, and your inflammation louder… you’re not imagining it.

One of the main “communication highways” tying all of that together is the vagus nerve—the longest cranial nerve in the body, connecting the brainstem to the heart, lungs, digestive tract, and immune signaling hubs.

What the vagus nerve does (in plain English)

Think of the vagus nerve as a two-way radio between your brain and your body:

It carries information UP to the brain about what’s happening in your gut, organs, and immune system.
It carries signals DOWN from the brain that influence heart rate, digestion, inflammation, and recovery.

This is why vagal tone (how well this system “communicates”) is so closely tied to stress resilience, digestion, mood stability, immune balance, and inflammation.

The inflammatory reflex

The brain’s built-in “inflammation brake”

Researchers describe a specific neuro-immune circuit called the inflammatory reflex—a pathway where the nervous system can turn down inflammatory cytokine output in the body.

Here’s the simplified sequence (matching the concept shown in that diagram):

1) The signal starts in the brainstem

When the vagus nerve is activated (think: slow breathing, relaxation response), the brain sends output down vagal pathways that can influence immune signaling.

2) The spleen acts like a relay station

The vagus nerve interfaces with splenic immune circuitry through the splenic nerve. In this pathway, signaling ultimately leads to norepinephrine release in the spleen, which then activates a specific subset of T-cells.

3) Immune T-cells release acetylcholine

This is one of the coolest parts: certain T-cells can produce acetylcholine, which functions like the “final messenger” in this anti-inflammatory circuit.

4) Acetylcholine tells macrophages to “stand down”

Acetylcholine binds to receptors (including α7 nicotinic acetylcholine receptors) on macrophages and can reduce inflammatory cytokine release, including TNF-α in experimental models.

Translation: inflammation isn’t only chemical—it’s also regulated by nerve signaling.

Why this matters for mental health and physical health

When vagal tone is low, people often get stuck in a “fight-or-flight” physiology:

faster heart rate, shallow breathing
tense muscles, poor digestion
disrupted sleep
more inflammatory signaling over time

This has real-world overlap with:

anxiety, overwhelm, irritability
IBS and gut sensitivity
chronic pain and tension patterns
autoimmune flare patterns and inflammatory symptoms
metabolic dysfunction (blood sugar swings and stress hormones feed each other)

On the measurement side, lower heart-rate variability (HRV)—one proxy for vagal tone—is associated in multiple studies with higher inflammatory markers like CRP and IL-6.

And interestingly, slow-paced breathing interventions have been studied for inflammatory effects (including reductions in IL-6 in some clinical contexts).

What affects vagus nerve function (positively and negatively)

What supports vagal tone

These are “high return” tools because they’re simple and they change physiology quickly:

Fast (1–5 minutes)

Slow breathing (longer exhales)
Humming / singing / chanting / prayer
Cold face splash or brief cool rinse
Gargling
Morning sunlight + calm breathing
Laughter + safe connection

Daily (10–20 minutes)

Walking (especially after meals)
Yoga, Tai Chi, mobility, gentle strength work
Meditation / breath prayer / gratitude practice
Massage / self-massage
Consistent sleep timing and evening low light

What tends to suppress vagal tone

Some are universal, some are individualized:

Sugar + refined carbs (blood sugar swings → stress response)
Alcohol (sleep disruption + inflammation)
Poor sleep + late night screens
Chronic stress without recovery rhythms

(For certain people, specific spices/foods can also aggravate symptoms—your body gets the final vote.)

Supplements that can support vagal tone (indirectly)

Supplements don’t “stimulate” the vagus nerve like breathing or cold exposure do—but they can make it easier for the nervous system to shift into parasympathetic mode by reducing excitability and inflammation.

Common options:

Magnesium (glycinate or threonate)
L-theanine
Glycine
Taurine
Omega-3 (EPA/DHA)
Targeted probiotics (strain matters for gut-brain signaling)

Always coordinate supplements with your Bedrock team member/ coach or clinician if pregnant, on SSRIs/SNRIs, thyroid meds, BP meds, anticoagulants, or if you have complex medical conditions.

What about vagus nerve stimulation devices?

There’s growing interest in both implanted and non-invasive vagus nerve stimulation approaches. In autoimmune conditions like rheumatoid arthritis, clinical trials have investigated vagus-targeted neuromodulation to reduce inflammatory activity and symptoms.

This is not a DIY medical recommendation—but it reinforces the same core message: your nervous system and immune system are in constant conversation.

A simple Bedrock “Vagal Tone” starter routine

If you want a practical starting point, do this for 7–14 days:

Morning