What is the Vagus nerve?
The vagus nerve is the tenth cranial nerve that exits the brain stem and descends down the back of the neck, through the chest, and into the abdomen, innervating all the internal organs. It provides the stimulation for swallowing and speaking, for heartrate and respiration and all the functions of the digestive, urinary, and reproductive tracts. It used to be thought that the vagus nerve was a single nerve that was responsible for the parasympathetic nervous system function, which was in opposition to the sympathetic nervous system.
Dr. Porges has proposed a different theory, called the Polyvagal Theory based on the two branches of the vagus nerve- the ventral branch and dorsal branch. (1) When the ventral vagus nerve function is dominant, we are in a state of calm relaxation and the capacity for positive social engagement with others. The dorsal vagus nerve is much older than the ventral branch and is found in all animals. This branch of the vagus nerve is associated with the “freeze” response that animals often have when they are in a severe stress state. When the dorsal vagus nerve is dominant, we are shut down, exhausted, depressed, and lethargic. The sympathetic nervous system is associated with “fight or flight” responses and when this part of the nervous system is dominant, we are stressed and can get overly active, irritable, agitated, even aggressive with increased tension through the body. (1)
The vagus nerve sends information to and from the internal organs and the brain and the enteric (gastrointestinal) nervous system as well as balances the input from the sympathetic nervous system. The main neurotransmitter released by the vagus nerve to accomplish all this is acetylcholine.
The health of the ventral vagus nerve is essential to healing because when we do not feel safe, we cannot heal. For many people with chronic illness, they feel betrayed by their bodies, and may have experienced betrayal or lack of support from family, friends, medical providers, and others in their community. A hypervigilant nervous system will often lead to a hyper-reactive body, which is just as detrimental as an underfunctioning, frozen nervous system and body. Restoring a sense of safety, calm, and rest is a requirement for all healing processes.
There are many ways to stimulate the vagus nerve more directly in addition to reducing stressors and adding treatments focused on calming the sympathetic response.
There is “growing evidence that nutritional components, such as probiotics, gluten, as well as drugs, such as anti-oxidative agents, and antibiotics, have a high impact on vagus nerve activity through the interaction with the gut microbiota.” (2) As such, taking a high quality probiotic may benefit digestion directly and support the vagus nerve. (3,4,6,7) Patients with MCAS or histamine intolerance may need to be aware of probiotic strains that increase or decrease histamine. Some strains that may increase histamine include Lactobacillus casei , bulgaricus , and helveticus, and Strep thermophilus. Stains that may decrease histamine include Bifidobacterium infantis, bifidum, breve, and longum, and Lactobacillus plantarum, rhamnosus, gasseri, and salivarius.
Breathing is well known to affect the state of the nervous system and we can change the way we breathe to influence the way our nervous systems function. Deeper, slower breathing increases vagus nerve tone and shifts the autonomic nervous system into the parasympathetic state. (3,5,6,7) Conscious breathing is a part of the Basic Treatment Guidelines of naturopathic medicine; in conscious breathing, we simply take time to focus on how we are breathing and take more conscious breaths through the day.
In general, you want to “ breathe more slowly, breathe more deeply, from the belly, and exhale longer than you inhale” (4). You also want to exhale through your mouth to make the exhalation a more conscious process. One source specifically recommended breathing in for two counts and holding for one count, then breathing out for four counts and holding for one count and repeating this process through the day. (5) Dr. Rosenberg has a specific exercise (discussed below) that can help open and ease breathing. (1) The Buteyko breathing technique (www.buteykoclinic.com) is another option that has specifically been used for issues associated with nervous system activation, like anxiety, stress, and panic attacks.
Meditation, especially with a focus on positive thoughts and gratitude, may stimulate the vagus nerve. (3,5,6,7) This could easily be combined with deep breathing and/or chanting. Meditation doesn’t have to be sitting cross-legged on the floor; it can be done in any seated, laying, standing, or moving position. People can meditate while doing the dishes, taking a shower, or taking a walk. The goal is calming the mind and reconnecting to life around us. During a walk, really observe the nature all around you and feel your place in it. Gratitude can be a great focusing point for meditation; people experience a real shift in their being when they focus on everyone and everything they love. It can also be helpful to set aside a place or have other sensory inputs (smell, lighting, sound, touch) that help to create the sensory association with a positive experience of meditation.
A search for “laughter therapy” in PudMed gave 629 studies. Studies have shown laughter can reduce blood sugar and complications of type 2 diabetes and change gene expression. Other studies showed laughter created cardiovascular effects similar to exercise and laughter can increase pain tolerance. Laughter may stimulate the vagus nerve and increase its tone. This may be demonstrated by some of the after-effects of too much laughter, including coughing, fainting, and involuntary urination, which are all controlled by the vagus nerve. (5,6,7) Therapeutic efficacy of laughter is mainly derived from spontaneous laughter (triggered by external stimuli or positive emotions) and self-induced laughter (triggered by oneself at will), both occurring with or without humor.
Limited studies have shown that acupuncture may stimulate the vagus nerve, especially points in the ears. (5) This is particularly interesting because the transcutaneous vagus nerve stimulation location (see below) is actually at a specific ear acupuncture point, Point Zero. This is one of the “master points” and “brings the whole body towards a general homeostatic balance, producing a balance of energy, a balance of hormones, and a balance of brain activity…Point Zero serves as the ‘Autonomic Brain’.” (8)
Aroma acu-therapy is another option, especially for patients who may be uncomfortable with needles, and is a very profound therapy for supporting the parasympathetic nervous system as well as working with personal and trans-generational trauma patterns. In aroma acu-therapy, essential oils are used on acupuncture points instead of needles and this allows the characteristics and energy of the plant oil itself to interact with the point in a unique combination.
Unlike other senses, the olfactory nerve doesn’t have to cross blood brain barrier. This means olfactory nerve is actually an extension of the brain and has a direct connection to brain. This may be why smell is the sense that most strongly evokes memories.
There is a class of scents called “euphorics” and this term refers to the experience induced in the person rather than any characteristic of the fragrance. These fragrances ensconce one in a “bliss” bubble, smooths and soothes the energy body, and stabilizes the Heart center and engenders safety. Some common examples include jasmine, rose, ylang ylang, neroli, sandalwood, cacao, and vanilla. This can be very specific to an individual. If you do choose to try aromatherapy, make sure you are using natural-source and high quality oils rather than synthetic ones.
Exposure to cold seems to turn down the sympathetic nervous response and this can be used to turn up the vagal nerve tone. (3,6,7) Studies in PubMed on the effects of cold exposure show it reduces blood sugar and improved insulin sensitivity in type 2 diabetics and healthy people, reduces heartrate, and increases certain proteins that can have anti-inflammatory effect. Studies in rats showed that acute cold exposure activates neurons in the digestive tract that are responsible for GI motility through the vagus nerve. Other rat studies showed prolonged exposure to cold increased pancreatic enzymes and digestive secretions, indicating that cold exposure may increase both GI movement and function.
The shower hydrotherapy that is part of the Basic Treatment Guidelines of naturopathic medicine recommends a cool to cold rinse for 30 seconds at the end of every shower. Cold exposure just to the face has also been recommended. Some sources indicate that the forehead, eyes, and upper 2/3 of cheeks need to be submerged in cold water in a bowl (4). Others indicate splashing cold water on your face as an option. (5) With all of these options, monitor how you feel and what temperature you can tolerate.
Singing can stimulate the muscles in the back of the throat and stimulate the vagus nerve. Some sources indicate this can also be done with humming, chanting, buzzing, or expressing the word “om” on the exhalation (3,4,5,6,7,10) and others indicate that singing must be done vigorously to get enough stimulation. (9) Especially for the buzzing and “om”, it works best if you are able to get into a comfortable position first, take a few deep breaths, make the sound as you slowly exhale, and allow your body to vibrate with the sound. (10)
Strong gargling may serve the same purpose as singing in that it is stimulating the back of the throat, and as such, stimulating the vagus nerve as it descends from the brain stem. (9) You can use plain water, but the gargling must be done vigorously and with the water at the back of the throat.
Stimulating gag reflex
Like singing and gargling, stimulating the gag reflex works to stimulate the back of the throat, which can stimulate the vagus nerve. (9) This is a much less pleasant option, so I generally don’t recommend this unless other methods haven’t worked.
Sleeping/Laying on your right side
Sleeping or laying on your right side seems to increase vagal tone more than laying on your left side or your back. (5,6,7)
Rubbing your belly
You can gently place your hand in the center of your belly and hold it there for a few moments. Rub your belly for several minutes in whatever way feels best to you. (10)
A search for “weighted blanket” in PubMed gave 301 studies. Numerous studies have shown them to be beneficial for anxiety and insomnia, reducing chronic pain, treating symptoms in late-stage dementia. Weighted blankets are thought to increase dopamine and serotonin and reduce cortisol.
Generally, you want weight of blanket to be 10% of body weight; the weight should help you feel safe, not trapped. Children should always be able to get out from under the blanket on their own. If a weighted blanket is too much, try a bag of rice or some other smaller weight that you can move to different parts of your body. You can also try an ice pack underneath to get both cold and weight.
Sit comfortably and allow your body to rock in whatever direction feels best to you at whatever speed feels best. (10) As the goal is to calm the nervous system, slower speeds are generally going to be more calming than faster ones. You can also rock just from your hips or just your head.
Sit comfortably and slowly rotate your right ankle 20 times in either direction within a comfortable range; you can then rotate it in the other direction (10). Then repeat with the other ankle, and then knees, hips, wrists, elbows, shoulders, pausing between rotations and joints. (10) This can be especially good to release trauma held in the joints. (10)
Omega-3 Fatty acids
Omega-3 fatty acids found in fish oil can stimulate vagus activity (5,6,7) and may support brain health and decrease inflammation systemically. Make sure you are using a good quality source that is tested for and free of PCBs, heavy metals, and other chemicals and has not been in a hot environment that would cause the oil to become rancid.
Because the main neurotransmitter of the vagus nerve is acetylcholine, supporting its production may provide some support for the vagus nerve. (5) Interestingly, acetylcholine is also the main neurotransmitter in the regulation of blood pressure and supporting acetylcholine is one of the treatment options for patients with POTS. These patients also often have dysregulation of the vagus nerve, which may also contribute to the POTS symptoms and dysautonomia. Given the choline cycle in the body, it may be more effective to use alpha-GPC or CDP-choline specifically for this purpose than just phosphatidylcholine.
Working with providers with Cranio-Sacral Therapy, Emotional Freedom Technique, or Frequency Specific Microcurrent can also be helpful. Doing T’ai Chi or Qi Gong, especially exercises designed to reduce stress and anxiety or focus on breathing may be best.
Stanley Rosenberg also describes exercises in his book Accessing the Healing Power of the Vagus Nerve: Self-Help Exercises for Anxiety, Depression, Trauma, and Autism, and has a YouTube video demonstrating the exercises. I have attached a handout describing his different exercises.
Trauma Release Exercises (TRE) developed by Dr. Bercelli are based on observations and work of Dr. Peter Levine. More information and instructions on these exercises are attached.
Other ideas I have used in practice or patients have reported to me include:
- Bathing in Epsom salts or bentonite clay (1/2 cup mixed in bath water; clay needs to be mixed with a whisk to get it to dissolve completely)
- Sleeping on an Earthing sheet (www.earthing.com)
- Skin-to-skin contact with someone you trust
- Body brushing with a sensory brush
- Laying on the floor with a small size pool noodle placed under your spine
- Getting outside in nature
- Standing barefoot on the earth
Vagal Nerve Stimulators
The vagus nerve can also be stimulated by direct, invasive nerve stimulation and indirect, transcutaneous stimulation. “Invasive VNS (iVNS) requires the surgical implantation of a small pulse generator subcutaneously in the left thoracic region. Electrodes are attached to the left cervical vagus nerve and are connected to the pulse generator by a lead, which is tunneled under the skin. The generator delivers intermittent electrical impulses through the vagus nerve to the brain.” (2) In transcutaneous nerve stimulation, the stimulator is “attached to the auricular concha via ear clips and delivers electrical impulses at the subcutaneous course of the afferent auricular branch of the vagus nerve.” (2)
There are also two options for DIY transcutaneous vagal nerve stimulators made from TENS units. Instructions can be found at https://www.instructables.com/DIY-Transcutaneous-Vagus-Nerve-Stimulator/ or https://cogenceimmunology.com/clinical-pearls-transcutaneous-vagus-nerve-stimulation/.
There may be even more options to increase vagus nerve tone, including different types of massage or exercise, or different types of electrical stimulation tools, and different methods may work differently for different people. With the exception of the invasive nerve stimulators, these ideas are all low-cost and low-risk options that may be effective in stimulating the vagus nerve.
The limbic system regulates emotion, sensitivity, cognition, energy, and pain; interprets our experiences; and regulates the balance of sympathetic and parasympathetic systems. It is beyond our conscious control and identifies if experiences are safe or not. If the limbic system becomes dysregulated, then it can perceive experiences to be unsafe, when they may in fact, be neutral or safe, which will lead to sympathetic and inflammatory response. Over time, the limbic system can get stuck in this hypervigilant and hyperreactive response, which will then dysregulate the parasympathetic nervous system function and healing.
There are many options programs that can be helpful in retraining the limbic system out of this hyper-reactivity. All brain retraining programs are based around the same research into neuroplasticity, which is the ability of our brain to change constantly. The adaptability and learning of the brain can both create pathways in the brain that can be problematic, which may cause us to get stuck in a fight/flight/freeze state, or we can use this knowledge to create pathways in our brain to support health, positive mood and a parasympathetic rest/digest/social state.
The basic steps include awareness/trigger, interruption, some form of acknowledgment, and visualization or mood elevation. This is a simple structure anyone can follow without a program, however, programs are useful in that they give you that structure, plus more information and support. Some programs require active participation and some are passive, and these programs could be combined. There are some that rely on sound or light may not be best choices for people with sensitivity in those areas. Please see the attached information about different types of limbic system retraining options.
(1) Rosenberg, Stanley. Accessing the Healing Power of the Vagus Nerve: Self-Help Exercises for Anxiety, Depression, Trauma, and Autism. 2017.
(8) Terry Oleson, PhD. Auriculotherapy Manual: Chinese and Western Systems of Ear Acupuncture. Second Edition. 1998.
(9) Mastering Brain Chemistry seminar; Dr. Datis Kharrazian, 2014.
(10) Resmaa Menakem. My Grandmother’s Hands: Racialized Trauma and the Pathway to Mending Our Hearts and Bodies. 2017.