Last night, I was listening to Sleepy Science on YouTube, like I often do. The episode focused on deep breathing and why it works. Because I’m a long-time practitioner of deep breathing and mediation, this subject piqued my interest. We all know deep breathing relaxes us. We’ve discussed the benefits a few times on TKZ.

For example, deep breathing:

• Reduces stress: Slow breaths trigger the parasympathetic nervous system, lowering stress hormone levels like cortisol.
• Eases anxiety: Controlled breathing calms panic and depressive symptoms by promoting a sense of safety and calm.
• Improves focus: Better oxygen flow to the brain clears brain fog and sharpens concentration.
• Promotes sleep: Deep relaxation before bed helps quiet the mind and supports restorative sleep cycles. This works, by the way. I do it every night before bed.
• Lowers blood pressure: Deep, rhythmic breathing relaxes blood vessels to ease the heart’s workload.
• Optimizes oxygen exchange: Belly breathing helps your lungs trade incoming oxygen for outgoing carbon dioxide more efficiently.
• Relieves pain and tension: Deep breathing releases muscle tension and minimizes pain. Speaking as a chronic pain sufferer, I know this to be true.
• Strengthens respiratory muscles: Diaphragmatic breathing trains your respiratory system to function with greater endurance and ease.

All those health benefits stem from triggering a single nerve in our body. Seems unfathomable, doesn’t it? But it’s true.

What is this nerve and its function?

The Vagus Nerve

The vagus nerve is the body’s main communication cable connecting the brain to major internal organs. It carries signals from your organs back to your brain, and from your brain out to your organs.

Vagus means “wandering” in Latin, and that’s exactly what it does. Actually, we have two, one for the left-side of our body, one for the right.

The vagus nerve starts at the base of the brain in an area called the medulla oblongata, which controls survival instincts, like breathing. The vagus nerve leaves the brain through a tiny hole in the bottom of the skull — called the jugular foramen — and runs down both sides of the neck, tucked inside a protective bundle of tissue beside major blood vessels, like the carotid artery and jugular vein.

On its way, it sends out small branches to the throat, voice box (larynx), and pharynx, helping us to swallow and speak.

From there, the vagus nerve passes behind the collarbone and enters the chest cavity, where it plugs into the heart to act as a natural brake system to slow our heart rate at rest. The vagus nerve then branches out into the lungs to manage breathing and contract airways.

The left and right vagus nerves merge as they pass through the diaphragm, located at the base of the ribcage below the lungs, and enters the abdominal cavity.

This is where the nerve spreads like a massive spider web, connecting to almost every part of the digestive tract, including the stomach, liver, pancreas, gallbladder, small intestine, and most of the large intestine. It tells these organs to release digestive fluids to move food along.

What an incredible journey!

According to the Poly Vagal Institute, that’s not all it does.

• Through its coordination with facial nerves, the vagus supports expressive communication.
• As a key component of the parasympathetic nervous system, the vagus modulates the body’s stress response.
• The vagus nerve contributes to speech by modulating vocal cord function and coordinating with respiratory rhythms, in concert with other cranial and cortical systems.
• The vagus nerve plays a key role in modulating immune function through what is known as the inflammatory reflex. It inhibits the release of pro-inflammatory cytokines from immune cells.

The science behind deep breathing lies in a biological loop between the heart, the lungs, and the brain.

When we change how we breathe, we manipulate physical pressure inside our chest, which tricks the brain into shifting from “fight-or-flight” to “rest-and-digest” mode. The main action boils down to two main scientific concepts — biomechanical pressure and chemical signals.

In a nutshell, deep breathing causes a chain reaction.

The vagus nerve doesn’t just read thoughts; it responds to physical movement and pressure.

Anyone who practices deep breathing knows the exhale is more beneficial than the inhale.

Do you know why? I thought I did, until I researched the vagus nerve.

When we inhale, our diaphragm moves down to create more space in the chest cavity. This pressure change allows blood to rush into the heart more easily, causing our heart rate to momentarily race.

When we exhale, our diaphragm rises and compresses the chest cavity. This compression shifts blood out of the heart, temporarily raising blood pressure within the local vessels.

Specialized pressure sensors (baroreceptors) on our major arteries detect this sudden pressure shift and send an urgent signal to the brainstem that says, “Blood pressure is too high—slow down!”

In response, the brain fires a signal to the vagus nerve. The vagus releases a neurotransmitter called acetylcholine directly onto the heart. Acetylcholine acts like a physical brake pedal, instantly slowing our heart rate and dropping our blood pressure.

The Secret Sauce

The secret to stimulating the vagus nerve is to prolong the exhale.

Because the vagus nerve is actively applying the “brake” when we exhale, a slower, longer exhale keeps the calming chemical signal flowing.

Ever have a panic attack?

The reason why it feels like you’re dying is because quick, shallow breaths keep your body locked into sympathetic (stress) dominance. The best way out of a panic attack is to inhale deeply, hold for a second or two, then exhale as slow as possible until you’ve completely emptied your lungs. Rinse and repeat.

Other ways to stimulate the vagus nerve:

• Getting restful sleep (deep breathing helps with this)
• Sunlight exposure (please use sunblock)
• Gargling & gag reflex (I’m addicted to mouthwash LOL)
• Daily movement & exercise (writers, you must get up and move!)
• Humming, chanting, and singing (during meditation or household chores)
• Laughter & social connection (as an introvert, I’ll stick to laughter & one close friend)
• Cold exposure (this also promotes anti-aging)
• Yoga & meditation (yes, indeed)

Why share this on a writing blog?

Because I adore you and want you to live your best possible life. <3 Deep breathing also promotes focus, concentration, and creativity.

TKZers, how do you stimulate your vagus nerve daily?