The Vagus Nerve: Your Body’s Built-In Calm Switch

If you’ve spent any time in the wellness space lately, you’ve probably heard the phrase “vagus nerve” thrown around — usually alongside cold plunges, humming, or deep breathing videos. There’s good reason for the hype. But there’s also a bit of nuance worth understanding, so let’s break down what’s genuinely well established, and what’s still an evolving area of science.

What Is the Vagus Nerve?

The vagus nerve is the longest cranial nerve in your body. It starts at the brainstem and travels down through your neck, chest and abdomen, connecting to your heart, lungs, and digestive system along the way. Think of it as one of your brain’s main lines of direct communication with your organs — carrying signals in both directions.

Rest, Digest, Regulate

The vagus nerve is the primary nerve of your parasympathetic nervous system — the branch of your nervous system responsible for slowing your heart rate, supporting digestion, and helping your body downshift out of “fight or flight” mode. When this system is functioning well, it’s often described in terms of “vagal tone.”

Higher vagal tone is associated with better stress resilience, steadier heart rate variability, and more efficient immune and digestive function. Lower vagal tone tends to show up alongside chronic stress and persistent inflammation. This part of the picture is well supported by decades of physiology research.

Where the Science Gets More Interesting (and More Debated)

You may also have come across “Polyvagal Theory,” developed by researcher Stephen Porges. It’s a framework describing how our nervous system might shift between different states — a calm, socially engaged state; a fight-or-flight state; and a shutdown state.

Polyvagal Theory has become hugely influential in trauma-informed and nervous-system-focused work, and many people find it a genuinely useful lens for understanding their own stress responses. It’s worth being upfront, though: several of its core physiological claims remain contested within academic neuroscience, and researchers are still actively debating exactly how the theory holds up. We think it’s a valuable framework to be aware of — just not one to treat as settled fact.

Simple, Evidence-Backed Ways to Support Vagal Tone

The good news is that you don’t need anything complicated to support this system. Some well-supported approaches include:

• Slow, deep breathing — particularly longer exhales than inhales
• Cold exposure — even something as simple as a cool splash of water on your face, or if you’re feeling braver – a cold shower for 30 seconds before turning the heat on, or jumping in your pool or the ocean for 2 mins in winter!
• Humming or singing — the vagus nerve runs close to your vocal cords
• Social connection — genuine face-to-face interaction has a measurable calming effect

Where Chiropractic Fits In

From a vitalistic perspective, we care about this because the nervous system is the foundation everything else runs on. Our focus when we adjust your spine is on making sure your nervous system is communicating clearly and functioning without interference, so your body has the best possible platform to regulate itself — whether that’s digestion, immunity, sleep, or your ability to handle stress.

We see this as complementary to the simple daily habits above, not a replacement for them. A well-supported nervous system responds to breathing exercises, cold exposure and connection more effectively — it’s all part of the same picture.

If you’d like to talk through how this fits into your own care, we’re always happy to chat at your next visit.

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