The Vagus Nerve: The “Gut Brain”
Ever used the following sayings?
“I’m sick to my stomach with worry”
“I’m so nervous , i’ve got butterflies in my belly”
“I’m bricking it with fear”
Ever wonder why stress affects our gut? I’ve been intrigued with the “gut brain” and the vagus nerve for some time now. I think that my curiosity has blossomed into love though; sparked by this book by Dr Navaz Habib and numerous articles that have come my way in the last couple of months. The most recent was published by Neuroscience News and reveals a relationship between Parkinson’s disease and the vagus nerve.
This study suggests there may be a link between constipation, the vagus nerve and Parkinson’s disease (note this is not to scare anyone - there are many reasons for constipation and more research is clearly needed). If it is true that chronic constipation and other digestive issues are early markers for Parkinson’s disease, then it make sense to take steps early in life to ensue a properly functioning gastrointestinal tract.
Researches have shown that chronic constipation/IBS is the second leading ailment that brings people to seek out reflexology. I can certainly agree with that - it’s been one of the top reasons people have sought out sessions from me.
The Vagabond Nerve
The wandering vagus nerve (vagus is Latin for “wandering”) is the most important nerve of the parasympathetic nervous system (the one responsible for the rest-and-digest mode). It’s also known as cranial nerve X - the tenth and longest of the cranial nerves to emerge from the posterior skull. It has approximately 1000 single nerve fibres and over 100 million nerve cells.
It starts in the brainstem, just behind the ears and travels down each side of the neck, across the chest and down through the abdomen, with stops along the way at the heart, lungs, spleen, liver and kidneys. Branching nerves are involved in speech, eye contact, facial expressions and even your ability to recognise other people’s voices.
A couple of points that that have really grabbed my attention are:
Ninety percent of serotonin produced by the body is found in the digestive track, not the brain, as previously believed. Serotonin is often prescribed for reasons of psychological health, but interestingly, also for digestive distress. That makes sense now. In addition, dozens of other neurotransmitters and hormones we thought only to exist in the brain and spinal cord are now known to also live in the intestines.
One of the more fascinating facts about the vagus nerve is that 20% of these nerve communicate to the organs in the gut, while an astounding 80% communicate back to the brain. That certainly explains why in traditional Chinese medicine (TCM), the gut is referred to as the second brain. Maybe it should be the first?
Vagal Tone
The strength of your vagus response is known as your vagal tone and it can be determined by using an electrocardiogram to measure heart rate. Every time you breathe in, your heart beats faster in order to speed the flow of oxygenated blood around your body. Breathe out and your heart rate slows. This heart rate variability (HRV) is one of many things regulated by the vagus nerve, which is active when you breathe out but suppressed when you breathe in, so the bigger your difference in heart rate when breathing in and out, the higher your vagal tone.
Research shows that a high vagal tone makes your body better at regulating blood glucose levels, reducing the likelihood of diabetes, stroke and cardiovascular disease. Low vagal tone, however, has been associated with chronic inflammation.
Inflammation
As part of the immune system, inflammation has a useful role helping the body to heal after an injury, for example, but it can damage organs and blood vessels if it persists when it’s not needed. One of the vagus nerve’s jobs is to reset the immune system and switch off production of proteins that fuel inflammation. Low vagal tone means this regulation is less effective and inflammation can become excessive.
“The vagus nerve works as a two-way messenger, passing electrochemical signals between the organs and the brain.”
In chronic inflammatory disease, it’s been found that signals from the brain telling the organs to switch off production of a particular inflammatory protein, tumour necrosis factor (TNF), aren’t being sent. Stimulating the vagus nerve might be the answer by switching off production of TNF. Perhaps the signals could be boosted?
Vagal nerve stimulation (VNS) is already being used for treating inflammatory diseases such as epilepsy, depression, Parkinson’s (and potentially Rheumatoid Arthritis) - via an implanted device that emits electric pulses directly on to the vagus nerve.
Having an electrical device surgically implanted into your neck for the rest of your life is a serious procedure. But the technique has proved so successful – and so appealing to patients who would otherwise be dependant on strong anti-inflammatory drugs – that other researchers are now looking into using vagal nerve stimulation for a range of other chronic debilitating conditions, including inflammatory bowel disease, asthma, diabetes, chronic fatigue syndrome and obesity.
Natural ways to improve Vagal Tone
Low vagal tone is associated with a range of health risks, whereas people with high vagal tone aren’t just healthier, they’re also socially and psychologically stronger – better able to concentrate and remember things, happier and less likely to be depressed, more empathetic and more likely to have close friendships.
Twin studies show that to a certain extent, vagal tone is genetically predetermined – some people are born luckier than others. But low vagal tone is more prevalent in those with certain lifestyles – people who do little exercise, for example.
Here are some natural ways to naturally improve your vagal tone:
Exposure to cold. Exposing your body to acute cold conditions, such as outdoor swimming, taking a cold shower or splashing cold water on your face and neck, increases stimulation of the vagus nerve. While your body adjusts to the cold, sympathetic (fight or flight) activity declines, while parasympathetic (rest-and-digest) activity increases.
Deep breathing. You can indirectly stimulate the vagus nerve by taking deep, deliberate breaths from your belly instead of your chest. Deep breathing activates specific neurons that detect blood pressure. These neurons signal to the vagus nerve that blood pressure is becoming too high, and the vagus nerve in turn responds by lowering your heart rate.
Exercise. Namely yoga - particularly of the Pranayama variety of yoga which focuses on the diaphragmatic or resilience breathing as explained above.
Meditation. Meditating is another great way to increase parasympathetic activity. It will bring your body in a state of calm, telling your vagus nerve that there is no need for a fight-or-flight response, thereby increasing vagal tone.
Singing. It’s less about hitting notes, it’s more about vibration and using your diaphragm. You can also use humming, and gargling to activate your vocal cords and the muscles in the back of your throat, which are connected to the vagus nerve. Incorporating these activities into your daily routine can help increase your vagal tone.
Complementary/Holistic Therapies. Acupuncture and Reflexology can stimulate the vagus nerve by working on the corresponding reflexes on the body and feet respectively. These treatments induce a deep state of relaxation, helping maintain homeostasis aka balance within the body and mind.
It’s become increasingly clear that we can’t continue to see organ systems in isolation anymore. The human is one entity: mind and body are one. It sounds logical but it’s not how modern medicine has looked at it before. We didn’t have the science to agree with what may seem intuitive. Now we have new data and new insights.
Who knows with more research into bioelectronic medicine, HRV and vagal tone could one day be used by GP’s as a diagnostic tool…
Are you stressed as hell? My Calm & Reset Package is focused on the central nervous system, where we induce regular states of deep relaxation to help mitigate the effects of stress and inflammation on the body and mind.
