What is the Vagus Nerve?
Roles and Functions
In people with fatigue, food sensitivities, anxiety, gut problems, brain fog, and depersonalization, the vagus nerve is almost always at play. These people have lower vagal tone, which means it has a lower ability to perform its functions.
The only question is which aspect of the vagus nerve is malfunctioning and to what extent it is the problem vs. other aspects of your biology.
The vagus nerve is part of the parasympathetic nervous system, referred to as the rest-and-digest system. It’s not the only nerve in the parasympathetic system, but it’s by far the most important one because it has the most far-reaching effects.
The word vagus means “wanderer,” because it wanders all over the body to various important organs.
The vagus nerve affects the brain, gut (intestines, stomach), heart, liver, pancreas, gallbladder, kidney, ureter, spleen, lungs, reproductive organs (female), neck (pharynx, larynx, and esophagus), ears, and tongue.
Given the importance of the vagus nerve to the gut (and other organs), when it’s not working properly, it will cause digestive disorders including dyspepsia, gastroparesis, GERD, ulcerative colitis, anorexia, and bulimia, to name a few.
How It Affects Your Body
In the brain, the vagus nerve helps mood and controls anxiety and depression.
The vagus nerve is largely responsible for the mind-body connection since it goes to all the major organs (except the adrenal and thyroid glands).
It’s intimately tied to how we connect with one another – it links directly to nerves that tune our ears to human speech, coordinate eye contact, and regulate emotional expressions. It influences the release of oxytocin, a hormone that is important in social bonding .
Studies have found that higher vagal tone is associated with greater closeness to others and more altruistic behavior .
Vagus activity of a child can be affected by their mother. Infants had lower vagus activity with mothers who were depressed, angry, or anxious during pregnancy .
Some studies suggested that the vagus nerve is important for getting in the mental state of “flow”. It’s believed that the combination of sympathetic (fight-or-flight) and vagus activation creates the right environment for a flow state .
Vagus nerve stimulation might increase wakefulness (by increasing orexin in the prefrontal cortex). It has been shown to decrease the amounts of daytime sleep and rapid eye movement in epilepsy patients with traumatic brain injury and also promoted the recovery of consciousness in comatose rats after traumatic brain injury .
However, the vagus nerve also might cause ‘sickness behavior’ (fatigue, sleepiness, depression, anxiety, appetite loss, pain, lowered motivation, and failure to concentrate) in an inflammatory state (IL-1b) .
In the gut, it increases stomach acidity, digestive juice secretion, and gut flow. Since the vagus nerve is important for increasing gut flow (motility), having less vagus activation will increase your IBS risk, which is a result of slower flow .
Stimulating the vagus nerve increases the release of histamine by stomach cells, which helps release stomach acid . So, low stomach acidity is usually, in part, a vagus nerve problem. By releasing the intrinsic factor, the vagus nerve is important to help you absorb vitamin B12.
Satiety and relaxation following a meal are in part caused by activation of the vagus nerve’s transmission to the brain in response to food intake .
The vagus nerve is important in conditions like GERD, not only because it controls stomach acidity, but also because it controls the esophagus.
Liver, Pancreas, and Gallbladder
In the liver and pancreas, it helps control blood glucose balance.
In the gallbladder, it helps release bile, which can help you get rid of toxins and break down fat.
In the heart, it controls heart rate and blood pressure. Vagus activation will lower the risk of heart disease, among other lethal diseases .
Kidney and Bladder
The vagus nerve promotes general kidney function. It helps with glucose control and increases blood flow, which improves blood filtration. Vagus activation also releases dopamine in the kidneys, which helps excrete sodium and, thereby, lower blood pressure [10, 11].
The vagus nerve also goes to the bladder. A side effect of its stimulation is urinary retention, which means that less vagus stimulation can cause you to urinate frequently. Indeed, many of my clients complain about frequent urination (also due to low vasopressin, low aldosterone, and high cortisol) [12, 13].
In the spleen, it can reduce inflammation. Note that vagus activation will reduce inflammation in all target organs (by releasing acetylcholine), but when it activates in the spleen the response will probably be more systemic .
It helps control fertility and orgasms in women by connecting to the cervix, uterus, and vagina. Women can actually experience orgasms simply from the vagus nerve.
Mouth and Ears
In the tongue, it helps control taste and saliva; while in the eyes, it helps release tears.
The vagus nerve explains why a person may cough when tickled on the ear, such as when trying to remove ear wax with a cotton swab.
Vagus nerve stimulation helps people with tinnitus because of its connection to the ear.
30 Ways to Stimulate the Vagus Nerve
Studies show that when your body adjusts to cold, your fight-or-flight (sympathetic) system declines and your rest-and-digest (parasympathetic) system increases, which is mediated by the vagus nerve .
Any kind of acute cold exposure will increase vagus nerve activation .
You can dip your face in cold water to start. I’ve graduated and now take fully cold showers, expose myself to cold, and drink cold water.
2) Singing or Chanting
Singing increases Heart Rate Variability (HRV) .
Humming, mantra chanting, hymn singing, and upbeat energetic singing all increase HRV in slightly different ways .
I do Om chanting in my infrared sauna.
Singing initiates the work of a vagal pump, sending relaxing waves through the choir .
Singing at the top of your lungs works the muscles in the back of the throat to activate the vagus.
Energetic singing activates both your sympathetic nervous system and vagus nerve, which helps to get into a flow state .
Singing in unison, which is often done in churches and synagogues, also increases HRV and vagus function .
Singing has been found to increase oxytocin .
A 12-week yoga intervention was associated with greater improvements in mood and anxiety than a control group who did walking exercises. The study found increased thalamic GABA levels, which are associated with improved mood and decreased anxiety .
There are two types of meditation that can stimulate the vagus nerve.
Loving-kindness meditation increases vagal tone, as measured by heart rate variability, and Om chanting .
5) Positive Social Relationships
In a study, participants were instructed to sit and think compassionately about others by silently repeating phrases like “May you feel safe, may you feel happy, may you feel healthy, may you live with ease,” and keep returning to these thoughts when their minds wandered.
Compared to the controls, the meditators showed an overall increase in positive emotions, like joy, interest, amusement, serenity, and hope after the class. These emotional and psychological changes were correlated with a greater sense of connectedness to others and to an improvement in vagal function, as seen by heart-rate variability.
Simply meditating, however, didn’t always result in a more toned vagus nerve. The change only occurred in meditators who became happier and felt more socially connected. Those who meditated just as much but didn’t report feeling any closer to others showed no change in the tone of the vagus nerve.
6) Deep and Slow Breathing
Deep and slow breathing stimulates the vagus nerve.
Your heart and neck contain neurons that have receptors called “baroreceptors.”
These specialized neurons detect your blood pressure and transmit the neuronal signal to your brain (NTS), which goes on to activate your vagus nerve that connects to your heart to lower blood pressure and heart rate. The result is a lower fight-or-flight activation (sympathetic) and more rest-and-digest (parasympathetic).
Baroreceptors can be variably sensitive. The more sensitive they are, the more likely they are going to fire and tell your brain that the blood pressure is too high and it’s time to activate the vagus nerve to lower it.
Slow breathing, with a roughly equal amount of time breathing in and out, increases the sensitivity of baroreceptors and vagal activation, which lowers blood pressure and reduces anxiety by reducing your sympathetic nervous system and increasing your parasympathetic system .
For an average adult, breathing around 5-6 breaths per minute can be very helpful.
Tip: You need to breathe from your belly and slowly. That means when you breathe in, your belly should expand or go out. When you breathe out your belly should cave in. The more your belly expands and the more it caves in, the deeper you’re breathing.
As the saying goes, laughter is the best medicine. Many studies show the health benefits of laughing .
It seems like laughter is capable of stimulating the vagus nerve.
A study done on yoga laughter found increased HRV (heart rate variability) in the laughter group .
There are various case reports of people fainting from laughter, which may be from the vagus nerve/parasympathetic system being stimulated too much.
For example, fainting can come after laughter, urination, coughing, swallowing, or bowel movements, all of which are helped along by vagus activation .
Laughter is also sometimes a side effect of vagus nerve stimulation .
Studies have shown that reciting the rosary prayer increases vagus activation. Specifically, it enhances cardiovascular rhythms such as diastolic blood pressure and HRV .
Studies also found that the reading of one cycle of the rosary takes approximately 10 seconds and thus causes readers to breathe at 10-second intervals (includes both in and out breath), which increases HRV and therefore vagus function .
Magnetic fields are capable of stimulating the vagus nerve. Studies have found that Pulsed Electromagnetic Field (PEMF) therapy can increase heart rate variability and increase vagus stimulation .
I use a pulsed magnetic stimulator called ICES in my gut and brain, which stimulates my vagus nerve increasing my appetite and stimulating me.
I recommend using this in your gut, brain, and side of your neck. My gut flow increases and inflammation is reduced everywhere when I put this on my gut.
At first, I didn’t understand how it can have systemic effects if I placed it on my gut, but the vagus nerve must be the main reason.
10) Breathing Exercises
Breathing in and out with resistance will likely stimulate your vagus nerve better—kind of like jogging with a backpack.
A breathing exercise is to breathe out as hard as you can until it’s really uncomfortable and until you notice how awake you are. I haven’t seen studies on this, but I suspect it will help with your vagus nerve.
The guts nervous system connects to the brain through the vagus nerve. There is increasing evidence pointing to an effect of the gut microbiota on the brain.
Massaging certain areas like your carotid sinus (located on your neck) can stimulate the vagus nerve. This helps reduce seizures .
Foot massages can also increase vagal activity and heart rate variability while lowering your heart rate and blood pressure .
All of these decrease the risk of heart disease.
Indeed, many anecdotal reports show that intermittent fasting benefits heart rate variability.
When you fast, part of the decrease in metabolism is mediated by the vagus nerve.
Specifically, the vagus detects a decline in blood glucose and a decrease of mechanical and chemical stimuli from the gut. This increases the vagus impulses from the liver to the brain (NTS), which slows the metabolic rate .
When we eat, the opposite happens. Satiety-related stimulatory signals from the gut contribute to increased sympathetic activity and stress-responsiveness (higher CRH, CCK, and lower NPY) .
The vagus nerve may make you more sensitive to estrogen. In female rats, fasting increases the number of estrogen receptors in certain parts of the brain (NTS and PVN), mediated by the vagus nerve .
15) Sleeping or Laying on Your Right Side
Studies have found that laying on your right side increases heart rate variability and vagal activation more than being on other sides. Laying on your back leads to the lowest vagus activation .
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16) Tai Chi
Tai chi increases heart rate variability and, therefore, very likely vagus activation .
The vagus nerve activates the muscles in the back of the throat that allow you to gargle.
Gargling contracts these muscles, which activates the vagus nerve and stimulates the gastrointestinal tract.
Before you swallow water, gargle it first.
18) Seafood (EPA and DHA)
I’m a big proponent of fish in the lectin avoidance diet.
I’ve taken 10 pills of fish oil as a megadosing experiment and my heart rate went from 60 to 40. So, in my self-experiments, fish oil does indeed lower heart rate, which is probably mediated, in part, by the vagus nerve.
Mice who had their vagus taken out didn’t exhibit the appetite-reducing effects of oxytocin .
21) Tongue Depressors
Tongue depressors stimulate the gag reflex.
Some say that gag reflexes are like doing push-ups for the vagus nerve while gargling and singing loudly are like doing sprints.
Acupuncture is so powerful that a man died after vagus nerve stimulation from too low of a heart rate .
So, serotonin has some mixed effects, but overall it should stimulate the vagus nerve. You can take 5-HTP to increase serotonin.
24) Chewing Gum
The ability of CCK to reduce food intake and appetite is dependent on the vagus nerve impulse to and from the brain .
Chewing gum helps increase CCK release.
25) Eating Fiber
Fiber is a good way to increase GLP-1 .
Expanding the bowel increases vagus nerve activation, as is done with enemas.
27) Coughing or Tensing the Stomach Muscles
When you bear down (as if to make a bowel movement), you stimulate your vagus nerve. That’s why you might feel relaxed after a bowel movement.
So, if you use the bowel movement muscles, it will stimulate your vagus nerve.
28) Thyroid Hormones
29) Sun Exposure
Alpha-MSH injection in the brain (DMV) moderately excites the vagus nerve in some conditions .
Sun exposure naturally boosts alpha-MSH .
30) Alpha-GPC (Acetylcholine)
While I haven’t seen any studies that alpha-GPC stimulates the vagus nerve itself, acetylcholine is the main vagal neurotransmitter. This means that it will have many of the effects of vagal stimulation.
Alpha-GPC is a good way to increase acetylcholine, but it’s not clear whether it will stimulate your vagus nerve.
Vagus Nerve Disorders
Your vagus nerve system can be messed up in 3 main ways:
- Communication from an organ to the brain.
- Communication within the brain.
- Communication from the brain to other areas of the body like the heart, liver, and gut.
1) Carbohydrates (Insulin)
Capsaicin is the most potent way to inhibit the vagus nerve.
- Obesity and weight gain .
- Brain problems
- Chronic fatigue
- High or low heart rate
- Difficulty swallowing
- Gastroparesis, also known as delayed gastric emptying,
- B12 deficiency
- Chronic inflammation
Conditions That Can Improve From Vagus Activation
Since the vagus nerve is associated with many different functions and brain regions, research shows the positive effects of vagal stimulation on a variety of conditions, including but not limited to:
- Anxiety Disorders
- Heart disease
- Alcohol addiction
- Multiple sclerosis
- Chronic heart failure
- Memory disorders
- Mood disorders
- Cancer .
- Bad blood circulation .
- Leaky Gut
- Severe mental diseases
The Vagus Nerve and Hormones
Orexin stimulates the vagus nerve from the brain, which promotes gut flow. It can stimulate the pancreas, too .
Orexin is capable of increasing glucose tolerance or insulin sensitivity via the liver vagus nerve .
Ghrelin stimulates the pancreas from the brain via the vagus .
Leptin-resistant animals were hungrier since the vagus nerve became less sensitive to CCK .
However, another study found that leptin effect on the vagus signal doesn’t play a major role in food intake .
CRH has variable effects on the vagus nerve. It decreases its activity from the brain to the heart. Vagus nerve activation will slow the heart rate, but CRH inhibits this and increases heart rate .
CRH stimulates the vagus impulse from the brain to the colon (by activating the dorsal nucleus of vagi, via cholinergic transmission) .
Vagus nerve stimulation normalizes an overactive nervous system (HPA axis) .
The vagus nerve can help reduce pain, and this is the mechanism by which estradiol reduces pain in certain circumstances .
Besides influencing the release of oxytocin, the vagus nerve is important for releasing testosterone. If it’s not working well, it could be the cause of low testosterone .
Testosterone can make people more aggressive, but this is not the case when the vagus nerve is functioning right .
The vagus nerve can stimulate other hormones such as parathyroid hormone, which is important for the conversion of vitamin D3 to active vitamin D (1,25) .
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Additional Vagus Nerve Resources
You can stimulate or inhibit the vagus nerve in two ways. First, the vagus nerve impulse (activation) can flow from the brain to the rest of the body or from the body to the brain.
When it flows from the brain it’s called a “vagal efferent.” When it flows from other parts of the body to the brain, it’s called a “vagal afferent.” I don’t use these terms for simplicity.
The low-frequency HRV is associated with both sympathetic (fight or flight) and parasympathetic (rest and digest) activation.
Genetic Testing for Vagus Activity
You can upload your genetic data to SelfDecode, and see if you have the version of the gene associated with low activity.
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The vagus nerve plays a central role in your rest-and-digest (parasympathetic) nervous system. Optimal vagus nerve activity supports digestion, metabolism, mental health, and cognition.
Countless health disorders such as IBS, leaky gut, IBD, GERD, brain fog, anxiety, and depression may have their roots in impaired vagal tone. Digestive and metabolic hormones, sex hormones, and growth factors require vagus nerve stimulation to work.
You can stimulate the vagus nerve naturally with yoga, meditation, prayer, cold exposure, singing, fasting, and massage.
Nutrients and supplements that may boost your vagus nerve activity include probiotics, fiber, zinc, omega-3 fatty acids, and 5-HTP.
On the other hand, carb-rich meals, ginger, and chili pepper may suppress your vagus nerve.