Do vagus nerve stimulators work for anxiety?

If you’ve been searching for new ways to get better slumber, you may have heard of vagus nerve stimulation (VNS) and, because you’ve tried a lot of things in vain, dismissed it.

But non-invasive vagus nerve stimulation (nVNS) is proving helpful for certain types of sleep disturbance. It’s not a universal cure, though. Details matter.

Here’s what the science says.

Why the vagus nerve affects sleep

The vagus nerve is the main arm of your parasympathetic nervous system — the system responsible for rest, recovery, and downregulation. It helps you shift out of fight-or-flight, slows your heart rate, reduces alertness and mental overactivity, and stabilizes breathing — all things you need to get good sleep.

If your nervous system stays subtly activated at night, if you go to bed in even a low-grade fight-or-flight state, you may feel that familiar tired-but-wired feeling.

One of the vagus nerve’s primary functions is to keep you coming back to rest-and-digest all through the day, especially before bed.

By stimulating the vagus nerve, you can enhance your body’s natural ability to find rest.

While vagus nerve stimulation has been studied for decades, the focus for a long time was on implanted stimulators. More recently, non-invasive vagus nerve stimulation (nVNS) — stimulation that happens through the skin — is growing in popularity as a promising tool to improve sleep quality.

Let’s explore what research shows about nVNS for sleep.

taVNS for post-stroke insomnia

One published case study using transcutaneous auricular VNS (taVNS) treated a patient with post-stroke insomnia.

After two weeks of receiving stimulation twice a day, not only did the patient’s sleep improve significantly but the patient was still getting better sleep at their three-month follow-up.

Brain imaging (fMRI) showed decreased activity in the default mode network (DMN) — a brain network often hyperactive in insomnia and rumination.

While this was only a single case, it supports the idea that vagus nerve stimulation may calm overactive brain networks linked to poor sleep.

Migraine-related sleep disturbance

People with migraines report more trouble sleeping than others.

A prospective observational study found that nVNS helped:

• Prevent migraines
• Treat acute attacks
• Improve migraine-associated sleep disturbance

This suggests vagus nerve stimulation may be particularly helpful when sleep issues are tied to nervous system dysregulation.

Ear stimulation and insomnia

Cranial electrotherapy stimulation (CES) — low-intensity electrical stimulation applied to the earlobes — is FDA-approved for insomnia, anxiety, and depression.

Although the earlobe has limited vagal innervation, brain scans show CES produces activation patterns similar to vagus nerve stimulation. The concha, cymba concha, and tragus are innervated by sensory branches of the vagus nerve.

These sensory nerve fibers carry the electrical signals of the stimulation into the brain, particularly the nucleus ambiguus, dorsal motor nucleus, hypothalamus, amygdala, and cortex. The hypothalamus controls your shifting between sleep and wakefulness.

The brain may be more receptive during sleep

Animal research shows that the brain’s response to vagus nerve stimulation changes across sleep stages.

Vagal-evoked brain responses are largest during non-REM sleep, suggesting the brain may be especially receptive to vagal input during deeper sleep phases.

We also know that vagal regulation differs across sleep states in newborns, highlighting the vagus nerve’s natural role in sleep architecture.

Are there risks?

Non-invasive VNS is generally considered safe.

However, implanted VNS devices (used for epilepsy and depression) have been associated with sleep-disordered breathing, increased obstructive apnea, snoring, and rare reports of insomnia.

These effects likely relate to stimulation intensity and influence on upper airway muscles.

Importantly, these findings do not automatically apply to modern non-invasive devices like your yōjō — but they do show that stimulation parameters matter.

So, can vagus nerve help me sleep?

Sleep isn’t just about melatonin levels. It’s about nervous system regulation.

Because the vagus nerve influences heart rate, inflammation, breathing, and brain network activity, stimulating it may help the body shift into a recovery state more effectively, beckoning sleep.

For people whose sleepless nights feel like a stress-response problem, vagal modulation could represent an important emerging option.

Vagal tone describes how responsive the vagus nerve is, particularly in regulating heart rate and stress responses, and how effectively the nervous system can return to balance after activation.

In simple terms, vagal tone reflects how easily your body can calm itself after stress.

The vagus nerve is the main nerve of the parasympathetic nervous system — the branch responsible for rest, digestion, recovery, and repair. Vagal tone reflects how strongly, and how flexibly, this system can influence the body to maintain internal balance, also known as homeostasis.

At a physiological level, vagal tone affects heart rate, breathing, digestion, inflammation, and emotional regulation. When vagal tone is high, the body can respond to stress and return to baseline efficiently. When it’s low, the nervous system is more likely to remain in a heightened state of activation.

The vagus nerve acts as a two-way communication pathway between the brain and the body, continuously carrying information about internal conditions and environmental demands. Vagal tone tells us how well that communication supports regulation.

In research and clinical settings, vagal tone is most often discussed in relation to stress resilience, emotional regulation, and cardiovascular health.

Why ‘tone’?

In physiology, ‘tone’ refers to baseline activity.

Muscle tone, for example, describes a muscle’s constant, low-level readiness to contract and relax. A muscle with healthy tone is responsive, not tense or rigid.

Vagal tone follows the same principle. It describes the ongoing influence of the vagus nerve at rest, and how easily that influence can increase or decrease as conditions change.

High vagal tone doesn’t mean the vagus nerve is constantly active. It means the nervous system has a strong capacity for regulation — the ability to slow things down when needed, and to release that influence when action is required.

How vagal tone works

One of the most important features of vagal tone is known as the vagal brake.

The vagus nerve contains fast, myelinated fibres that connect directly to the heart’s pacemaker (the sinoatrial node). These fibres act as a brake on heart rate.

When vagal influence is high, the brake is applied, slowing the heart and supporting calm, restorative states. When reduced, the brake is released, allowing heart rate to rise and support attention, movement, or mobilization.

This braking and releasing happens continuously. A well-functioning vagal brake allows the body to respond to changing demands without becoming stuck in a prolonged stress response.

How vagal tone is measured

Vagal tone isn’t measured directly. Instead, it’s inferred from patterns in heart rate — most commonly through respiratory sinus arrhythmia (RSA).

RSA refers to the breath-by-breath changes in heart rate that occur naturally as you breathe. Heart rate increases slightly during inhalation and slows during exhalation.

The size of this breath-linked change in heart rate reflects how strongly the vagus nerve is influencing the heart.

• Higher RSA is associated with stronger cardiac vagal tone
• Lower RSA suggests reduced vagal regulation

RSA is widely used in research as a marker of autonomic flexibility: the nervous system’s ability to adapt to stress and return to baseline.

Vagus nerve stimulation (VNS) and vagal tone

Vagal tone is shaped by repeated signals to the nervous system, particularly signals that support parasympathetic activity and recovery.

Both invasive and non-invasive forms of VNS influence vagal activity, often reflected as increases in heart rate variability and improvements in autonomic balance. By directly stimulating vagal pathways, VNS can engage the same regulatory circuits involved in slowing heart rate, reducing inflammation, and supporting recovery.

Far from forcing relaxation, regular VNS changes how efficiently the nervous system can apply and release vagal influence over time, which is a core feature of healthy vagal tone.

Why vagal tone matters

Vagal tone is widely considered a physiological marker of stress vulnerability and resilience.

Lower vagal tone is associated with poorer emotional regulation, chronic low-grade inflammation, cardiovascular disease, depression, and stress-related disorders.

Higher vagal tone supports emotional stability, physiological calm, and the processes involved in growth, restoration, and repair.

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If you’re wellness aware, you’ve probably heard of the vagus nerve. And, if you’re smart enough to be skeptical of praises and promises in the wellness space, you’re probably looking to know more about the “body’s calm switch” and why this one nerve can do so much.

What is it? Where is it in the body? What information does it carry? How does it help the body to regulate?

Simple answers to these questions will help you better understand the vagus nerve’s influence on stress, digestion, inflammation, mood, and social connection. It will become clear why this particular nerve is becoming more prominent for well-being and why vagus nerve-based therapies and interventions often produce broad effects, rather than isolated symptom changes.

Let’s take a quick wander around what has been called “The Wanderer”.

The vagus nerve and its connections

The vagus nerve — 10th cranial nerve — is the longest of the cranial nerves and the primary component of the parasympathetic nervous system. Its name comes from the Latin vagus, meaning “wandering,” reflecting its path from the brainstem through the neck, chest, and abdomen, connecting your brain to your heart, lungs, gut, liver, spleen, and kidneys.

It was first described in the second century by Galen of Pergamon, a prominent Roman physician. He recognized the vagus nerve’s importance for vitality and linked it to life force.

Despite being talked about as a single nerve, the vagus nerve is actually a pair of nerves running down the sides of your body. And despite being spoken of as a motor nerve, the vagus nerve is mostly sensory.

Roughly 80% of its nerve fibres are afferent, carrying sensory information from the body to the brain. The other 20% send signals from the brain to the organs.

This makes the vagus nerve less of a command system and more of an information superhighway coordinating multiple systems to help maintain homeostasis — the body’s internal balance, especially when it comes to stress, recovery, digestion, and feeling safe.

It is involved in heart rate, blood pressure, breathing, digestion, immunity, mood, speech, and even taste.

In practical terms, the vagus nerve helps your body do three key things:

Calm down after stress

The vagus nerve is a core part of the parasympathetic “rest-and-digest” system. It counterbalances the fight-or-flight response and helps bring the body back into balance once a challenge has passed.

One of its roles is acting as a “vagal brake” on the heart, gently slowing the heart rate and supporting a state of calm, flexible alertness rather than constant tension.

It’s also a major pathway in the microbiome–brain–gut axis, enabling gut activity and microbial signals to influence mood, cognition, and emotional regulation.

This helps explain why chronic stress often shows up as digestive issues — and why improving nervous system regulation can change how the body responds to stress overall.

Manage inflammation

The vagus nerve helps keep inflammation in check.

Through a built-in inflammatory reflex, it can signal the immune system to reduce excessive inflammatory responses, helping protect the body from chronic, stress-related inflammation.

When inflammation rises in the body, afferent vagal fibers signal the brain. In response, efferent vagal pathways help dial down excessive immune activity through a mechanism called the cholinergic anti-inflammatory pathway — CAP for short.

CAP is a loop involving the vagus nerve and acetylcholine, a neurotransmitter.

1. Your body detects inflammation and lets your brain know by sending signals up the vagus nerve.
2. The brain sends a signal back down the vagus nerve, calling for the release of acetylcholine.
3. Acetylcholine, once released, finds immune cells called macrophages and attaches to specific receptors on the cells.
4. The cells stop releasing inflammatory chemicals.

It may seem like immune suppression, but this regulatory process is essential for long-term resilience because it prevents overreactive immune responses.

Feel safe

The polyvagal theory suggests that for mammals, being social is a biological necessity for regulating our bodies and surviving. We use social cues (like a soothing voice or a smile) to tell each other's nervous systems that we are safe, which turns off the defensive, inflammatory systems. And the vagus nerve is central to this sociality.

Through its connections with muscles of the face, throat, and ears, the vagus nerve helps regulate facial expression, vocal tone, listening, and speech.

This, according to the theory, is why a sense of calm, and its opposite, can spread around a room.

Balance is key

The vagus nerve isn’t really a switch you flip. That has been a handy analogy, but it doesn’t explain how complex and nuanced the vagus nerve’s work is.

It’s more like a learning pathway, continuously updating the brain about internal states and shaping how the body responds to stress, connection, recovery, and challenge.

Lasting calm emerges when regulatory systems are trained, consistently and gently, to identify threats, recognize safety, and adapt quickly but never too much of one and not enough of the others. Homeostasis is the final and most vital goal.

And that’s why working with the vagus nerve tends to change more than one thing at a time.

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