Good vagal nerve function is crucial for optimal health. Emerging research suggests that it might not function well in many chronic disease states. In this post, we will review factors that may increase its tone with stimulation and how this can affect health.
19 Factors that May Stimulate the Vagus Nerve
When to See a Doctor
If your goal is to stimulate your vagus nerve to improve your mood- or extreme stress-related issues – including those of panic disorders or anxiety – it’s important to talk to your doctor, especially stress if it is significantly impacting your daily life.
Major mental changes, such as excessive sadness, panic, persistent low mood, euphoria, or anxiety, are all reasons to see a doctor.
Your doctor should diagnose and treat any underlying conditions causing your symptoms.
Remember that the existing evidence does not suggest that low vagal tone causes anxiety or mood disorders. Complex disorders like anxiety always involve multiple possible factors – including brain chemistry, environment, health status, and genetics – that may vary from one person to another.
Additionally, changes in nerve tone and brain chemistry are not something that people can change on their own with the approaches listed here. Instead, the factors mentioned in this article are meant to reduce daily stress and support overall mental health and well-being. Most are backed up only by limited human or animal studies.
Therefore, you may try the strategies listed below if you and your doctor determine that they could be appropriate. Read through the approaches we bring up and discuss them with your doctor before trying them out. This is particularly important if you plan to take any dietary supplements.
Supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective.
Finally, have in mind that none of these strategies should ever be done in place of what your doctor recommends or prescribes.
1) Cold
According to one study on 10 healthy people, when the body adjusts to cold temperatures, your fight-or-flight (sympathetic) system declines and your rest-and-digest (parasympathetic) system increases, which is mediated by the vagus nerve. In this study, temperatures of 50°F (10°C) were considered cold [1].
Sudden cold exposure (39°F/4°C) also increases vagus nerve activation in rats [2].
Although the effects of cold showers on vagus nerve tone haven’t been studied, many people advocate for this traditional cooling method.
When we think about it, all showers were cold showers before the advent of water-heating techniques. Anecdotally, cold tubs are popular in Japan, while many Northern nations partake in dips in the ocean for special occasions during the winter or early spring.
It usually takes a while to get accustomed to fully cold showers, though. Some people say it’s good to dip your face in cold water for starts.
Remember to consult your healthcare provider first, though. Most doctors recommend against cold showers in people with heart disease or in those at risk. That’s because sudden cold exposure can restrict blood vessels, which may raise heart rate and blood pressure.
2) Singing or Chanting
According to one intriguing study on healthy 18-year-olds, singing increases Heart Rate Variability (HRV) [3].
Heart rate variability has been associated with relaxation, better stress resilience and adaptation, and higher rest-and-digest (parasympathetic) activity [4, 5].
The authors of the mentioned study found that humming, mantra chanting, hymn singing, and upbeat energetic singing all increase HRV in slightly different ways [3].
They hypothesized that singing initiates the work of a vagal pump, sending relaxing waves through the choir [3].
Additionally, singing at “the top of your lungs” might work the muscles in the back of the throat to activate the vagus [3].
On the other hand, the authors of this study think that energetic singing activates both the sympathetic nervous system and vagus nerve, which might help people get into a flow state [3].
Singing in unison, which is often done in churches and synagogues, also increased HRV and vagus function in this study [3].
However, no other similar studies have been carried out. The above-discussed study included only fifteen healthy 18-year-olds. We don’t know how various types of singing and chanting affect the vagus nerve in people of different ages or suffering from mental health problems. Larger studies are needed.
In the only other study dealing with this connection, singing was found to increase oxytocin in both professional and amateur singers [6].
Both groups felt energized after a singing session, but amateur singers said they sense greater well-being and less arousal than professionals. The authors pointed out that this might be because amateurs approached singing as a relaxation and self-realization technique, while the professionals were achievement-oriented [6].
Therefore, you may want to relax and express yourself as much as possible when singing and chanting. Try not to think about how you sound and whether you’ll reach the goals you set for that session.
3) Yoga
Limited studies suggest a link between yoga and increased vagus nerve and parasympathetic system activity in general [7, 8].
A 12-week yoga intervention was more strongly associated with improvements in mood and anxiety than walking exercises, which served as the control group. The study found increased thalamic GABA levels, which are associated with improved mood and decreased anxiety [7].
Yoga is thought to be good for supporting overall mental and physical health [9, 10]. More research is needed on its effects on the vagus nerve tone.
4) Meditation
Studies suggest that at least three types of meditation may stimulate the vagus nerve indirectly. In small studies, loving-kindness meditation, mindfulness meditation, and Om chanting increased heart rate variability, which is linked to vagal tone [11, 12].
Some scientists think that conscious, deep breathing that accompanies meditation and other contemplative practices might underlie this effect. Attentive breathing is hypothesized to directly stimulate the vagus nerve and rest-and-digest nervous activity [12].
Larger studies and more human studies on various types of meditation are needed.
5) Positive Thoughts and Social Connection
In a study of 65 people, half of the 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 [13].
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 [13].
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 [13].
Although more research is needed, these findings suggest that the vagus nerve is tied to how positive emotions and social connections may help people on a path to better health.
6) Deep and Slow Breathing
Deep and slow breathing is also hypothesized to stimulate the vagus nerve, and it’s likely common to various types of meditation, yoga, and relaxation techniques.
Your heart and neck contain neurons that have receptors called “baroreceptors” [14].
These specialized neurons detect blood pressure and transmit the neuronal signal to the brain (NTS). If a person’s blood pressure is high, this signal goes on to activate their vagus nerve, which connects to the heart to lower blood pressure and heart rate. The result is less fight-or-flight activation (sympathetic) and more rest-and-digest (parasympathetic) activity [14].
Baroreceptors can be variably sensitive. Some scientists suspect that the more sensitive they are, the more likely they are going to fire and tell the brain that the blood pressure is too high and it’s time to activate the vagus nerve to lower it [14].
One study tested the effects of yogic slow breathing called ujjayi, which can be performed at various rates of breathing in and out, on 17 healthy people. With a roughly equal amount of time breathing in and out, ujjayi breathing increased the sensitivity of baroreceptors and vagal activation, which lowered blood pressure [15].
This type of slow breathing involved 6 breaths per minute, which would be about 5 seconds per inhale, 5 seconds per exhale [15].
Some researchers think that yogic slow breathing might also reduce anxiety by reducing the sympathetic nervous system and increasing the parasympathetic system, but this hasn’t been confirmed yet [15].
Tip: Yoga practitioners point out that you need to breathe from your belly, slowly. That means when you breathe in, your belly should expand or go outward. 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.
7) Laughter
There may be some truth to the saying “laughter is the best medicine.” A couple of studies suggest the health benefits of laughing [16].
Scientists suggest that laughter might be capable of stimulating the vagus nerve, claiming that laughter therapy is something that may be powerful for health. Yet studies are still few and it’s hard to say exactly how and why laughter makes us feel so good [17]
A study done on yoga laughter found increased HRV (heart rate variability) in the laughter group [17].
However, there are various case reports of people fainting from laughter. Doctors point out that this may be from the vagus nerve/parasympathetic system being stimulated too much.
For example, some research suggests that fainting can come after laughter, urination, coughing, swallowing, or bowel movements, all of which are helped along by vagus activation [18].
There are case reports of people passing out from laughter who have a rare syndrome (Angelman’s) that’s associated with increased vagus stimulation [19, 20].
Laughter is also sometimes a side effect of vagus nerve stimulation that is performed with special devices in children with epilepsy [21].
Some researchers want to know whether a good bout of laughter is good for cognitive function and heart disease protection. Limited studies suggest that laughter increases beta-endorphins and nitric oxide, which theoretically benefit the vascular system [16, 22].
8) Prayer
One small study found that reciting the rosary prayer may increase vagus activation. Specifically, it seemed to enhance cardiovascular rhythms, reducing diastolic blood pressure and increasing HRV [23].
According to one research group, 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 [3].
9) PEMF
Some scientists hypothesize that magnetic fields may be capable of stimulating the vagus nerve. In a study on 30 healthy men, Pulsed Electromagnetic Field (PEMF) therapy increases heart rate variability and vagus stimulation. However, no other studies have replicated these findings [24].
PEMF devices are classified as general wellness products. They have not been approved by the FDA for treating any condition.
10) Probiotics
Emerging evidence points to an effect of the gut microbiota on the brain. The gut’s nervous system connects to the brain through the vagus nerve, which has been described as “at the interface of the microbiota-gut-brain axis” [25].
Some animal studies have looked at the potential effects of probiotics on the vagus nerve, but clinical trials are still lacking.
In an animal study, mice supplemented with the probiotic Lactobacillus rhamnosus experienced various positive changes in GABA receptors that were mediated by the vagus nerve [26].
GABA receptors in the brain are implicated in mood; a potential link between vagus nerve gut stimulation by L. rhamnosus and enhanced GABA activity adds to a body of emerging evidence about the potential health benefits of probiotics [26].
11) Exercise
Mild exercise stimulates gut flow in animals – and vagus nerve activation was needed to initiate this response. Thus, some scientists hypothesize that exercise may stimulate the vagus nerve, though there’s no human evidence to support this theory [27].
12) Massage
Massaging certain areas like the carotid sinus (located on your neck) can stimulate the vagus nerve. Research suggests that it may help reduce seizures [28]. (note: massaging a carotid sinus is not recommended at home due to possible fainting and other risks)
A pressure massage may also activate the vagus nerve. These massages helped infants gain weight by stimulating the gut and this is thought to be largely mediated by vagus nerve activation [29, 30].
Reflexology foot massages are also claimed to increase vagal activity and heart rate variability while lowering heart rate and blood pressure, according to one small study on healthy people and patients with heart disease [31].
13) Fasting
Intermittent fasting and reducing calories both increase heart rate variability in animals, which is thought to be a marker of vagal tone [32].
Some people claim that intermittent fasting improved their heart rate variability, but no clinical trials can attest to this effect.
According to one theory, the vagus nerve might mediate a reduction in metabolism upon fasting. Specifically, the vagus detects a decline in blood glucose and a decrease of mechanical and chemical stimuli from the gut. This seems to increase vagus impulses from the liver to the brain (NTS), which slows the metabolic rate, according to animal data [33].
Animal studies suggest that hormones such as NPY increase while CCK and CRH decrease during fasting [33].
The opposite may happen after eating. Satiety-related stimulatory signals from the gut appear to contribute to increased sympathetic activity and stress-responsiveness (higher CRH, CCK, and lower NPY) [33].
The vagus nerve may make animals more sensitive to estrogen when they are hungry. In female rats, fasting increases the number of estrogen receptors in certain parts of the brain (NTS and PVN), which may be mediated by the vagus nerve [34].
14) Sleeping or Laying on Your Right Side
Limited studies suggest that laying on your right side increases heart rate variability and vagal activation more than being on other sides. Laying on the back led to the lowest vagus activation in one study. More research is needed [35].
15) Tai Chi
In one study on 61 people, tai chi increased heart rate variability and, therefore, likely vagus activation [36].
16) Seafood (EPA and DHA)
According to several scientific reviews, omega-3 fatty acids EPA and DHA increase heart rate variability (HRV) and lower heart rate. HRV is directly linked to vagus nerve stimulation [37, 38].
Some scientists think that vagus nerve activity might explain why omega-3 fatty acids are good for the heart, but more research is needed [37, 38].
Additionally, fish is an important part of the lectin avoidance diet.
17) Zinc
Zinc increased vagus stimulation in rats fed a zinc-deficient diet for 3 days [39]. It’s a very common mineral that some people don’t get enough of.
18) Acupuncture
According to limited research, traditional acupuncture points may stimulate the vagus nerve, especially those on the ears [40, 41].
Acupuncture is not always safe. In one report, a man died after vagus nerve stimulation from too low of a heart rate. Make sure to work with a qualified acupuncture practitioner and let your doctor know if you plan to see an acupuncturist [42].
19) Eating Fiber
GLP-1 is a satiating hormone that stimulates vagus impulses to the brain, slowing the gut movements and making us feel fuller after meals [43].
Animal research suggests that fiber may be a good way to increase GLP-1 [44].
Sun Exposure?
We don’t yet know if sun exposure can stimulate the vagus nerve, though this is theoretically possible.
Alpha-MSH prevents damage from a stroke in rats via activating the vagus nerve, which suppresses inflammation [45, 46].
Alpha-MSH injection in the brain (DMV) moderately excites the vagus nerve in some conditions [47].
Sun exposure is hypothesized to natural boosts alpha-MSH, but it would be a long stretch to say that sun exposure can stimulate the vagus nerve. Future studies would need to look into this[48].
Experimental (Lacking Evidence)
The following factors are theoretical or anecdotal. They aren’t backed up by solid science, and they are not generally associated with well-being. We recommend against them but think that they’re interesting to mention for informational purposes.
Gargling
The vagus nerve activates the muscles in the back of the throat that allow you to gargle.
Theoretically speaking, gargling contracts these muscles, which may activate the vagus nerve and stimulate the gastrointestinal tract.
Tongue Depressors
Tongue depressors stimulate the gag reflex. The vagus nerve is directly connected to the muscles on the back of the throat that control this reflex [49].
Some say that gag reflexes are like doing push-ups for the vagus nerve while gargling and singing loudly are like doing sprints. Unfortunately, there’s no solid science to back this up.
Chewing Gum
CCK (a gut hormone) seems to directly activate vagal impulses in the brain [50].
The ability of CCK to reduce food intake and appetite is dependent on the vagus nerve impulses to and from the brain [51].
Chewing gum might help increase CCK release, but most gum is not healthy and contains artificial sweeteners and other additives [52].
Coughing or Tensing the Stomach Muscles
When you bear down (as if to make a bowel movement), you may manage to mechanically stimulate your vagus nerve. Some even say that this is why people feel relaxed after a bowel movement. Still, science is lacking to suggest that simulating bowel movements will stimulate the vagus nerve.
Alpha-GPC (Acetylcholine)
No studies suggest that alpha-GPC stimulates the vagus nerve. Some people think it might, since it might increase acetylcholine, which is the main vagal neurotransmitter.
This means that it may, in theory, have effects on vagal stimulation, but we don’t know if this actually happens when someone takes alpha-GPC supplements.
Enemas
Expanding the bowel increases vagus nerve activation. Enemas expand the bowel, but they carry many risks when they’re not used under medical supervision. Using enemas at home can be particularly dangerous. Frequent use can cause severe electrolyte imbalances and even death.
Potential Inhibitors
These are all experimental. No human trials are available to determine how these compounds affect the vagus nerve in humans. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts.
1) Carbohydrates (Insulin)
Insulin, which the body releases after meals, seems to suppress the part of the vagus nerve innervating the liver. High insulin levels seen in obesity may compromise the normal function of the vagus nerve and therefore, the liver, but more research is needed [53].
2) Capsaicin
In animal experiments, capsaicin is thought to be the most potent (and spicy) way to inhibit the vagus nerve. There’s no evidence that eating spicy, capsaicin-rich foods blocks the vagus nerve in humans, though [54].
3) Ginger
Ginger is hypothesized to prevent nausea and vomiting by inhibiting the vagus nerve and serotonin function in the digestive tract. We don’t know if eating ginger reduces vagus nerve activity. Ginger, in general, is a healthy spice and there’s no reason to avoid it, unless directed by your doctor [55, 56].
Takeaway
The vagus nerve plays a central role in the rest-and-digest (parasympathetic) nervous system.
Factors that may stimulate the vagus nerve naturally include yoga, meditation, prayer, cold exposure, singing, fasting, and massage. Nutrients and supplements that are being researched for boosting vagus nerve activity include probiotics, fiber, zinc, and omega-3 fatty acids. Research is still limited. Be sure to consult a doctor before taking supplements or making major lifestyle changes.
