What is the vagus nerve?
The vagus nerve is cranial nerve X, a paired nerve (left and right) that leaves the brainstem, exits the skull beside the jugular vein and runs down the neck and chest into the abdomen. It connects the brain to the throat, heart, lungs and most of the digestive tract, carrying signals in both directions.
Its name comes from the Latin vagus, “wandering”, because no other cranial nerve travels so far from the head. Along the way it gives off branches to the larynx (your voice box), the heart, the airways, the oesophagus, the stomach, the liver, the pancreas and the intestines as far as roughly the middle of the large bowel. A small branch even reaches the skin of the outer ear, which is why touching the ear canal can occasionally trigger a cough.
Inside the brainstem, three areas do most of the work. The nucleus tractus solitarius receives incoming information from the organs. The dorsal motor nucleus sends outgoing signals mainly to the gut. The nucleus ambiguus sends signals to the heart, throat and voice box.1
The most useful thing to know is the direction of traffic. Roughly 80% of vagal fibres are sensory: they report what is happening in the body (stretch in the stomach, blood pressure, inflammation, gut contents) up to the brain. Only around 20% carry commands back down.1 So the vagus is less a switch the brain flips and more a continuous conversation between brain and body.
What does the vagus nerve do?
The vagus nerve is the main pathway of the parasympathetic nervous system, the “rest and digest” side that balances the “fight or flight” stress response. It slows the heart, drives digestion, controls swallowing and voice, helps regulate inflammation and carries gut-to-brain signals that shape appetite and mood.
| Fight or flight | Rest and digest | |
|---|---|---|
| Main driver | Sympathetic nerves, adrenaline | Parasympathetic nerves, mostly the vagus |
| Heart | Faster, harder beats | Slower, more variable beats |
| Breathing | Faster, upper chest | Slower, lower, longer out-breath |
| Digestion | Slowed, deprioritised | Acid, enzymes and gut movement switched on |
| Built for | Short bursts of action | Recovery, repair and sleep |
Applies the brake
Vagal fibres to the heart's pacemaker slow the resting heart rate. Without them, the heart would beat at around 100 beats a minute.
Runs rest-and-digest
Stimulates stomach acid and enzyme release, relaxes the stomach to receive food, and coordinates the muscle waves that move it along.
Swallowing and speech
Branches supply the muscles of the soft palate, pharynx and larynx, including the gag reflex and the vocal cords.
The inflammatory reflex
The vagus senses inflammation and can signal to dampen it, a circuit first described in 2002 and called the inflammatory reflex.2
Reports from the gut
Sensory fibres relay fullness, nutrients and signals linked to gut microbes up to the brain: the core of the gut–brain axis.3
Airways and reflexes
Controls airway tone and mucus, and carries stretch signals from the lungs that help set the rhythm of breathing.
The vagus nerve can also overreact. Vasovagal syncope, the most common cause of fainting, happens when a trigger such as pain, the sight of blood or standing for a long time causes a sudden surge of vagal activity that drops heart rate and blood pressure. So the goal is not “more vagus” but a system that responds flexibly.
What is vagal tone, and how is it measured?
“Vagal tone” describes how much steady influence the vagus nerve has over the body at rest, especially over the heart. It cannot be measured directly, so researchers estimate it from heart rate variability (HRV): the small beat-to-beat changes in timing between heartbeats. Higher resting HRV generally reflects stronger vagal influence.
Your heart does not beat like a metronome. When you breathe in, vagal braking eases and your heart speeds up slightly. When you breathe out, the brake comes back on and it slows. This rhythm is called respiratory sinus arrhythmia, and its size is one of the clearest windows onto vagal activity.4
Two cautions matter here. First, HRV depends heavily on age, fitness, breathing rate, posture, time of day and medication, so a single reading from a watch is a rough signal rather than a verdict. Second, “vagal tone” is shorthand for a pattern, not one fixed number. Lower resting HRV is consistently associated with psychological stress,5 but that link runs both ways and does not by itself diagnose anything.
How is the vagus nerve connected to the gut?
The vagus nerve is the main direct nerve link between the digestive system and the brain. It signals the stomach to relax and secrete acid, coordinates the muscle waves that move food through the gut, and sends information about fullness, nutrients and inflammation back up to the brain, which is why stress so often shows up as digestive symptoms.
The gut has its own nervous system of hundreds of millions of neurons, the enteric nervous system, which can run digestion on its own. The vagus acts as the line between that system and the brain: it adjusts the pace and tells the brain what is going on.3
This two-way link explains a familiar experience. Under stress, the fight-or-flight system takes priority, parasympathetic activity falls, and digestion is deprioritised: appetite drops, the stomach empties differently, and some people get bloating, urgency or discomfort. The reverse also happens: signals from an irritated or inflamed gut travel up the vagus and can affect mood and alertness.
Researchers are also studying how gut microbes talk to the brain through the vagus. In one well-known study, a Lactobacillus strain changed anxiety-like behaviour in mice, and the effect disappeared when the vagus nerve was cut.6 That is animal research and does not show the same happens in people, but it is a big reason the vagus sits at the centre of gut–brain science.
Between meals, the small intestine also runs a housekeeping wave called the migrating motor complex, which depends on the same acetylcholine signalling the vagus uses. We cover this properly, from stress and bloating to the cleaning wave and the nutrients behind it, in the vagus nerve and digestion.
What are the signs your rest-and-digest system is struggling?
There is no validated list of “low vagal tone symptoms”. What people commonly describe is a body that switches on easily but struggles to switch off: feeling tired but wired, digestion that reacts to stress, slow recovery after a stressful moment, and sleep that doesn't feel restorative. These patterns are non-specific and have many possible causes.
With that caveat, these are the patterns that tend to cluster together when the balance tips toward stress and away from recovery:
- Exhausted but wired. Tired all day, then alert the moment your head hits the pillow.
- Stress-reactive digestion. Appetite, bloating or bowel habits that shift with how stressed you are.
- Slow to come down. Heart still racing, or thoughts still spinning, long after the stressful thing has passed.
- Sleep that doesn't restore. Enough hours, but waking unrefreshed.
- Shallow, upper-chest breathing and frequent sighing, especially when concentrating.
- A consistently low HRV for your age on a wearable, taken over weeks rather than a single night.
We go deeper on each of these, and on what lowers vagal tone, in signs of low vagal tone. If several sound familiar, our free vagus pattern assessment takes two minutes and points you to where to start.
- Fainting, or dizziness when you stand up
- Difficulty swallowing, or a hoarse voice lasting more than three weeks
- Persistent vomiting, feeling full after a few mouthfuls, or unexplained weight loss
- A very slow, very fast or irregular heartbeat, chest pain or breathlessness
- Blood in your stool or vomit, or a change in bowel habit lasting more than a few weeks
These need a proper medical assessment and are not something to manage with habits or supplements.
What happens if the vagus nerve is damaged?
Damage to the vagus nerve (vagal neuropathy) can slow stomach emptying (gastroparesis), causing nausea, early fullness and vomiting. It can also cause hoarseness or difficulty swallowing, an abnormal heart rate and dizziness. Common causes include long-standing diabetes, surgery in the neck, chest or abdomen, and some viral infections.
Diabetes is the most common cause of gastroparesis linked to nerve damage: years of high blood sugar can injure the autonomic nerves, including the vagus. Surgery is another. Before modern ulcer drugs, surgeons deliberately cut branches of the vagus (a vagotomy) to reduce stomach acid, and slower stomach emptying was a known side effect.
These are medical conditions diagnosed with tests such as gastric emptying studies, and they are managed by doctors. They are quite different from the everyday stress–recovery patterns in the section above.
How can you support your vagus nerve naturally?
The best-supported way to increase vagal activity is slow breathing at around six breaths a minute with a longer out-breath, which reliably raises heart rate variability. Exercise, good sleep and cold water on the face also have evidence behind them, and nutrition supplies what the nerve’s messenger is built from. Humming, gargling and similar “hacks” have little direct research.
Here is how the most popular approaches compare, graded twice: Science (how well established the biology is) and Trials (controlled studies measuring vagal activity).
| Approach | What it does | Science | Trials |
|---|---|---|---|
| Slow breathing (~6 per minute) | Longer out-breaths strengthen the vagal brake on the heart and raise HRV, with consistent effects on relaxation measures.78 | Strong | Strong |
| Regular aerobic exercise | Fitter people tend to have higher resting HRV. Training over weeks raises it, although the session itself briefly lowers it. | Strong | Good |
| Cold water on the face | Triggers the diving reflex, a vagal slowing of the heart. A cold stimulus to the neck raised vagal activity in a randomised trial.9 | Strong | Good |
| Nutrition: the acetylcholine nutrients | The vagus nerve’s messenger is built from choline and acetyl-CoA, which depends on B1, B2, B5 and magnesium. Omega-3 DHA slows resting heart rate in trials. More below. | Strong | Moderate |
| Consistent sleep | Vagal activity normally rises during deep sleep. Short or broken sleep is linked to lower HRV the next day. | Good | Good |
| Social connection & positive emotion | Higher baseline vagal tone predicted greater gains in social connectedness and positive emotion, which in turn raised vagal tone.10 | Moderate | Moderate |
| Humming, singing, gargling | These use muscles supplied by vagal branches, so the idea is plausible, but there is very little direct research. | Moderate | Early |
| Ear (auricular) stimulation devices | Target the vagal branch in the outer ear. It is an active research field, but results are mixed and devices vary widely. | Good | Early |
For every method in detail, including yoga, gut health, nutrition and what the device research actually found, see how to stimulate your vagus nerve: 11 methods compared.
Breathe in through your nose for 4 seconds, then out slowly for 6. That works out at six breaths a minute. Keep the breath low and quiet, into the belly rather than the upper chest. Five minutes is enough to feel the shift, and a daily habit is where the benefit builds. Our free guided breathing timer paces it for you.
Where to start, by pattern
Pick the one that sounds most like you and start there. Doing one thing daily beats doing five occasionally.
Slow breathing for five minutes before bed, screens off 30 minutes earlier, and the same wake time every day, weekends included.
Three slow breaths before each meal, eat sitting down without a screen, and a ten-minute walk after your largest meal.
Morning daylight within an hour of waking, exercise earlier in the day, and a cool, dark bedroom. Track HRV as a weekly trend, not a nightly score.
Not sure which fits? The two-minute vagus pattern assessment will tell you.
What about vagus nerve stimulation (VNS)?
Medical VNS uses a device implanted in the chest, wired to the vagus nerve in the neck. It is an established treatment for some cases of drug-resistant epilepsy and, in some countries, treatment-resistant depression.11 It is a specialist medical therapy, and quite different from the consumer gadgets and wellness trends that borrow its name.
Can you “reset” your vagus nerve?
Not in the way social media suggests. There is no single exercise that resets the nerve. What you can do is repeatedly practise the conditions under which the rest-and-digest system engages (slow breathing, recovery, sleep, safe connection), so the switch back down happens more easily over time.
Do vagus nerve supplements work?
Supplements don’t stimulate the vagus nerve; they supply it. The nerve’s messenger, acetylcholine, is built from choline and acetyl-CoA, which depends on thiamine, riboflavin, pantothenic acid and magnesium. That science is strong. Trials of top-ups in healthy people are fewer, with omega-3 DHA the best studied for slowing resting heart rate.
Every signal the vagus nerve sends to your heart and gut is delivered as acetylcholine, and your body rebuilds it from nutrients each time.12 Severe thiamine deficiency is a classic cause of nerve damage: beriberi affects peripheral and autonomic nerves, including those serving the gut.12 So the science question, whether the vagus nerve needs these nutrients, has a clear answer: yes.
The trial question is newer. Across 51 randomised trials, omega-3 supplements slowed resting heart rate, with DHA driving the effect.13 High-dose omega-3 also raised resting HRV in adults with raised triglycerides,14 and a small 2025 trial reported improved measures of vagal function after a multi-species probiotic.15 Large trials of the B1 and choline pathway in people who aren’t deficient are still to come.
So treat nutrition as the foundation everything else runs on: cover the nutrients your vagus nerve depends on every day, then build the habits above on top. Intake can run low with heavy alcohol use, very restrictive diets, some medications and after weight-loss surgery.
Which nutrients does the vagus nerve depend on?
Each one in depth, with food sources, daily needs and who tends to run low: vitamins for the vagus nerve. For thiamine specifically, see thiamine and digestive health.
Vagus One: the nutrition half of vagus nerve health
Breathing, movement, sleep and connection ask your vagus nerve to fire. Vagus One supplies what it fires with. It’s built around the acetylcholine pathway: citicoline for the choline half, and thiamine with benfotiamine, pantothenic acid, riboflavin-5-phosphate, magnesium bisglycinate and acetyl-L-carnitine for the acetyl-CoA half, plus L-theanine and saffron. No fillers or binders.
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Vagus nerve FAQs
Where is the vagus nerve located?
The vagus nerve starts in the brainstem at the base of the skull, runs down each side of the neck alongside the carotid artery and jugular vein, passes through the chest behind the heart and lungs, and goes through the diaphragm into the abdomen, where it branches to the stomach, liver, pancreas and intestines.
Which side is the vagus nerve on, left or right?
Both. There is a left and a right vagus nerve. The right mainly influences the heart's pacemaker (the sinoatrial node), and the left mainly influences the atrioventricular node. In the abdomen they form the front and back vagal trunks that supply the stomach and gut.
Can anxiety affect the vagus nerve?
Stress and anxiety shift the nervous system toward fight or flight, and studies consistently link psychological stress with lower heart rate variability, a marker of vagal activity. The relationship runs both ways, which is why slow breathing, which increases vagal activity, is widely used to help settle anxious states.
Does deep breathing stimulate the vagus nerve?
Slow breathing does, more than deep breathing as such. Breathing at around six breaths a minute with a longer out-breath increases the vagal brake on the heart and raises heart rate variability. Fast, deep breathing does not have the same effect and can make you feel lightheaded.
How long does it take to improve vagal activity?
A single session of slow breathing changes heart rate variability within minutes, but the effect fades afterwards. Lasting changes in resting heart rate variability from regular breathing practice or aerobic exercise are usually seen over several weeks of consistent practice.
What does a vagus nerve problem feel like?
True vagus nerve damage tends to cause nausea, early fullness and vomiting from slow stomach emptying, a hoarse voice, difficulty swallowing, dizziness or an abnormal heart rate. These need medical assessment. Everyday stress patterns such as feeling tired but wired, or stress-reactive digestion, are different and far more common.
What vitamins are good for the vagus nerve?
No vitamin has been shown to stimulate the vagus nerve directly. Thiamine (B1), riboflavin (B2) and magnesium contribute to the normal functioning of the nervous system, and pantothenic acid (B5) contributes to the normal synthesis of some neurotransmitters, so an adequate intake supports normal nerve function.
What is the best supplement for the vagus nerve?
Look for one that covers both halves of acetylcholine, the vagus nerve’s messenger: a choline source such as citicoline, plus thiamine (ideally with benfotiamine), pantothenic acid, riboflavin and magnesium, at printed doses. Yona’s Vagus One is built around exactly this pathway. Add omega-3 DHA from oily fish, and keep slow breathing and sleep as the base.
Is vagus nerve stimulation safe?
Implanted vagus nerve stimulation is an established medical treatment for some drug-resistant epilepsy and depression, used under specialist care, with side effects such as hoarseness and coughing. Non-invasive ear and neck devices are generally well tolerated in studies, but the evidence for everyday wellness use is still limited. Speak to your doctor first if you have a heart condition.
References
- Breit S, Kupferberg A, Rogler G, Hasler G. Vagus nerve as modulator of the brain–gut axis in psychiatric and inflammatory disorders. Front Psychiatry. 2018;9:44. doi:10.3389/fpsyt.2018.00044
- Tracey KJ. The inflammatory reflex. Nature. 2002;420:853–859. doi:10.1038/nature01321
- Bonaz B, Bazin T, Pellissier S. The vagus nerve at the interface of the microbiota–gut–brain axis. Front Neurosci. 2018;12:49. doi:10.3389/fnins.2018.00049
- Laborde S, Mosley E, Thayer JF. Heart rate variability and cardiac vagal tone in psychophysiological research. Front Psychol. 2017;8:213. doi:10.3389/fpsyg.2017.00213
- Kim HG, Cheon EJ, Bai DS, Lee YH, Koo BH. Stress and heart rate variability: a meta-analysis and review of the literature. Psychiatry Investig. 2018;15(3):235–245. doi:10.30773/pi.2017.08.17
- Bravo JA, Forsythe P, Chew MV, et al. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. PNAS. 2011;108(38):16050–16055. doi:10.1073/pnas.1102999108
- Zaccaro A, Piarulli A, Laurino M, et al. How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Front Hum Neurosci. 2018;12:353. doi:10.3389/fnhum.2018.00353
- Lehrer PM, Gevirtz R. Heart rate variability biofeedback: how and why does it work? Front Psychol. 2014;5:756. doi:10.3389/fpsyg.2014.00756
- Jungmann M, Vencatachellum S, Van Ryckeghem D, Vögele C. Effects of cold stimulation on cardiac-vagal activation in healthy participants: randomized controlled trial. JMIR Form Res. 2018;2(2):e10257. doi:10.2196/10257
- Kok BE, Fredrickson BL. Upward spirals of the heart: autonomic flexibility, as indexed by vagal tone, reciprocally and prospectively predicts positive emotions and social connectedness. Biol Psychol. 2010;85(3):432–436. doi:10.1016/j.biopsycho.2010.09.005
- Johnson RL, Wilson CG. A review of vagus nerve stimulation as a therapeutic intervention. J Inflamm Res. 2018;11:203–213. doi:10.2147/JIR.S163248
- Overton E, Emelyanova A, Bunik VI. Thiamine, gastrointestinal beriberi and acetylcholine signaling. Front Nutr. 2025;12:1541054. PMC12014454
- Hidayat K, Yang J, Zhang Z, et al. Effect of omega-3 long-chain polyunsaturated fatty acid supplementation on heart rate: a meta-analysis of randomized controlled trials. Eur J Clin Nutr. 2018;72(6):805–817. doi:10.1038/s41430-017-0052-3
- Sauder KA, Skulas-Ray AC, Campbell TS, Johnson JA, Kris-Etherton PM, West SG. Effects of omega-3 fatty acid supplementation on heart rate variability at rest and during acute stress in adults with moderate hypertriglyceridemia. Psychosom Med. 2013;75(4):382–389. doi:10.1097/PSY.0b013e318290a107
- Mörkl S, et al. Multi-species probiotic supplement enhances vagal nerve function: results of a randomized controlled trial in patients with depression and healthy controls. Gut Microbes. 2025;17(1):2492377. doi:10.1080/19490976.2025.2492377
Last reviewed on 24 September 2026. Every factual claim is linked to published research. Yona makes Vagus One, which is featured in the nutrition section. Spotted something out of date? Email hello@meetyona.co.uk.
This guide is for general information and is not medical advice. Speak to your GP or pharmacist before starting a supplement if you are pregnant, breastfeeding, taking medication or managing a health condition. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.