The Vagus Nerve and Breathing
Mary Taylor
The speed and the different pathways with which our bodies talk to themselves is remarkable. Scientists first identified neurotransmitters in 1926; now more than 100 substances have been identified as playing a role in signal transmission between nerves. Nerve impulses travel at speeds of up to 100 meters per-second. In comparison, the fastest flow of blood in the body (in the aorta) is 30 cm per-second (more than 300 times slower than nerve impulses) and elsewhere in the body it is significantly slower.
Three nerve pathways that are very important to our function are the olfactory nerve, the phrenic nerve and the vagus nerve. The olfactory nerve is the shortest of the cranial nerves, running from nose to forebrain. It conveys information relating to smell and is involved in the limbic system.
The phrenic nerve is the main nerve of the respiratory system and can be associated, to some extent, with the sympathetic nervous system. It runs between the neck and the diaphragm, having two branches that pass through the heart and lung. It passes motor information to the diaphragm and receives sensory information from it. It is the phrenic nerve that regulates our breathing. Without a functioning phrenic nerve, then literally there is no life. Breathing is controlled by the phrenic nerve.
The vagus nerve, the main nerve of the parasympathetic nervous system, supplies parasympathetic fibers to all the major organs of the head, neck, chest and abdomen. It runs between the brain and the abdomen. Messages go both ways, though most, about 80%, go from body to brain. Essentially the body informs the brain, and the brain informs the body. It is probable, therefore, that the information that goes from diaphragm to brain has significant importance for our well-being.
In the brain, the vagus nerve helps to control anxiety and depression. In the heart, it controls the heart rate and blood pressure. In the liver and pancreas, the vagus nerve helps to control blood glucose balance. In the gallbladder, it helps release bile, which can help get rid of toxins and break down fat.
The vagus nerve promotes general kidney function. Vagus activation also releases dopamine in the kidneys. In the tongue it helps to control tase and saliva; in the eyes it helps to release tears and influence the release of oxytocin (a hormone that plays a role in social bonding).
The “tone” of the vagus nerve indicates emotional, mental and physical health. Tone is influenced by childhood experiences, genetics and adult life events. This tone can be seen as how resilient we might be. If a person has experienced trauma, their vagel tone will likely be lower. There is some evidence suggesting that lower resilience makes a person more prone to experiencing PTSD, whereas higher resilience means that a person is less likely to exhibit these behaviors.
Psychology professor (Chapel Hill), Barbara Fredrickson, explains how vagal tone can change: “Scientists used to think vagal tone was largely stable, like your height in adulthood. Our data shows that this part of you is plastic and altered by your social habits. Your brain is tied to your heart by your vagus nerve. Subtle variations in your heart rate reveal the strength of this brain-heart connection and, as such, heart-rate variability provides an index of your vagal tone. By and large, the higher your vagal tone, the better. It means your body is better able to regulate the internal systems that keep you healthy, like your cardiovascular, glucose and immune responses”.
By increasing people’s vagal tone, we increase their capacity for connection, friendship and empathy. In short, the more attuned to others you become, the healthier you become and vice versa. This mutual influence also explains how a lack of positive social contact diminishes people. Your heart’s capacity for friendship also obeys the biological law of “use it or lose it.” If you don’t regularly exercise your ability to connect face to face, you may eventually find yourself lacking some of the basic biological capacity to do so.
Indicators of vagal tone include a persons’ body language, their facial expressions and their voice. Researcher Stephen Porges states, “as social human beings, we are much more interested in the intonation of the voice that we are in the content.” What we are experiencing with our face shows what is going on in the body, essentially (in the words of Porges): “are we safe to come close to?”
There are a multitude of moves (often slight and subtle) that we can do with our hands, tongue, face and eyes that significantly change input for the autonomic nervous system. Breathing is one of the key ways we can control our nervous systems and one that is generally easily accessible. When we slow our breathing, it is sometimes in order to slow our heart rate. Those who’ve experienced, physical, emotional and/or psychological trauma are more likely to struggle with practices that involve breath control.
As Fredrickson points out, vagal tone can be indirectly observed by measuring heart rate variability (HRV). A good way of influencing HRV is through coherent breathing. An acronym for this technique is BREATHE (Breathe Rhythmically Evenly At the Heart of the belly Everyday). By breathing more with the belly, we can perhaps shift away from fear states. Though fear is a basic emotion that has played an essential role in our survival, too much fear can be damaging to our health.
The following suggestions may help with anxiety and the pursuit of a happier, more fulfilled and productive approach to daily life:
Breathe slowly
Speak with smiles and changing vocal sounds
Exercise our social relationships (remember social bonds are not only good for you but for others as well) They are generally good for or health
When we feel safer, we are more likely to get physically closer with other people which assists social bonding.
BELLY BREATHING
Breathing from the belly is not always easy, even for experienced yogis. It has been suggested that a difficulty in belly breathing for some yoga practitioners is an over emphasis on (and misunderstanding of) bandhas. Overly strong abdominal tone can impact the pelvic and respiratory diaphragms which move in concert, both moving down on the inhale and up on the exhale. Potentially this diaphragm movement can be disrupted by overly aggressive mulabandha or uddiyanana bandha techniques or overly active abdominal muscles in general. These approaches can make abdominal breathing more challenging.
Richard Brown, MD and Patircia Gerberg, MD (Breath-Body-Mind Foundation) noted that “belly breathing and coherent breathing…shift the nervous system response into a healthier balance by activating the healing, recharging part of the nervous system while quieting the defensive, energy-burning parts.” According to a 2017 research paper, “it is not to be mistaken that slow breathing practice should minimize sympathetic activity, but rather, that it appears capable of achieving optimal sympathovagal balance, and enhancing autonomic reactivity to physical and mental stress…Of great scientific interest is the effect of long-term practice of slow breathing.”
They suggest that our 24/7 culture with its striving for hormonal highs, such as the dopamine (a neurotransmitter that plays a role in how we feel pleasure) hit from social media can mean higher levels of adrenalin (a hormone that can increase blood circulation and breathing and also prepares muscles for exertion). One consequence of this 24/7 culture could be imbalances of the vagus nerve and lowered vagal tone. Brown and Gerberg also note that: “When people are under stress, their breathing becomes shallow and their shoulders tend to go upward.” Given this it follows that a possible path for lessening stress is to consciously avoid sources of intense stimulation. In addition, lessening stress and so increasing connectivity may also be approached by slowing the breath and softening shoulders away from the ears.
Here are seven simple ways to stimulate the vagus nerve and so reap these benefits throughout the body:
Cold studies have shown that when the body adjusts to cold, the sympathetic system increases (as there is constricting of blood vessels). A splashing of face with cold water can be a start; cold showers and cold water swimming can be great.
Singing and chanting: this includes humming, mantra chanting, hymn singing and so on.
Yoga, meditation (particularly loving kindness forms of meditation), mild exercise and movement forms like tai chi.
Positive social relationships and laughter.
Probiotics, quercetin (found in green tea, gingko biolo, apples, etc.), Vitamin C
Gargling: this stimulates muscles of the palate which are fired by the vagus nerve.
Resting and sleeping on your right side. Studies have found that lying on the right side increases HRV and vagel tone activation more than being on the left side.
Norman Blair began practicing yoga in the early 1990s and he has been teaching since 2001. His practice and teaching embrace both Ashtanga yoga and Yin yoga as well as mindfulness meditation.
Norman's own experience has taught him that yoga is an enjoyable way to release and make available energetic potential to enhance our lives. Yoga can help us to become more flexible, physically stronger and improve our stamina, focus and awareness. He believes that yoga is accessible to all of us and through regular practice we can experience profound changes in our mind and body.
Norman teaches Ashtanga and Yin yoga classes and workshops throughout London, as well as leading retreats. He has run yoga teacher mentoring groups for more than ten years and is the author of "Breathing Our Inner Skies: Yin and Yoga."
