Vagus Nerve — The Gut–Brain Hotline
A wandering nerve that carries more gossip from your organs to your brain than the other way around.
The vagus nerve is the main nerve of the gut–brain axis. It leaves your brainstem, dives down through your neck and chest, and branches across the heart, lungs and digestive tract. Around 80–90% of its fibres are afferent — meaning they send information from body to brain. Your brain is less the CEO barking orders and more the group chat moderator, constantly reading incoming messages from the organs.
From the gut’s side, the vagus nerve reports on stretch (how full things are), motility (how waves of contraction are moving), and chemical signals from nutrients and microbes. When your stomach is pleasantly stretched after a fibre‑rich meal, the vagus sends “we’re good” messages that support calm parasympathetic tone. When the gut is irritated or inflamed, the tone of those signals shifts — part of why gut distress can feel like anxiety, and anxiety can loop back to make the gut twitchier.
The vagus nerve also carries outgoing commands that slow the heart rate, support digestion, and dampen inflammatory responses — this is the parasympathetic, “rest‑and‑digest” side of your nervous system. Techniques like slow breathing, humming, singing, or cold water on the face play with this circuitry, nudging vagal activity upward and helping some people feel more grounded in both body and mind.
In gut health research, the vagus shows up everywhere: from how certain probiotics seem to affect mood in animals (vagus intact vs. cut) to how chronic stress can reduce vagal tone and change gut motility. You don’t need to obsess over it, but it’s a helpful reminder that your nervous system, your gut, and your microbes are literally wired together.
Why It Matters
The vagus nerve turns abstract ideas like “mind–body connection” into anatomy — a tangible route by which breath, food, and feelings talk to each other all day long.
Closing Line
Every calm breath, every unhurried meal is a tiny love note sent along the vagus — a reminder to your brain that, at least for this moment, you’re safe enough to digest.