The vagus nerve… Being a highly visual person with a vivid imagination, when I first heard about the vagus nerve I was instantly transported to Las Vegas and Elvis. What is this exciting shiny rhinestone-covered thing with celebrity status?! Little did I know how close I was to the truth, with the celebrity bit anyway.
Known as the wandering nerve (from the same root as the word vagrant), it is the longest and most branched cranial nerve in the human body. It starts in the brain stem and meanders its way down, connecting with our internal organs and ending up branching out into all parts of our digestive system. It is the primary two-way communication channel for mood, using neurotransmitters.
For those who read my column regularly you may recognise this from the last two issues where I mentioned the gut-brain-axis and the bi-directional communication of the gut and brain. The vagus nerve has a huge impact on our nervous system and plays an important role in the functioning of certain organs using both sensory and motor functions. For example, even before we begin eating the digestive process has started its preparation simply from seeing and smelling the food. The vagus nerve sends a signal to start the production and secretions of stomach acids that help digest food and kill off any unwanted pathogens. Putting it simply, our nervous system has two parts: the central nervous system, consisting of the brain and spine; and the peripheral nervous system made up of the autonomic - with three anatomically distinct divisions: sympathetic, parasympathetic and enteric, and the somatic nervous system.
The vagus nerve represents the main component of the parasympathetic nervous system which controls actions we do unconsciously, such as breathing and digestion, our heart rate and blood pressure and reflex actions such as coughing, sneezing, swallowing and vomiting. The parasympathetic nervous system, known as ‘rest and digest’ or ‘feed and breed’, is the desired state of being, where we are relaxed, calm, happy and ready to procreate! So, you can begin to see why healthy vagal tone is so important.
Sympathetic nervous system dominance ‘fight or flight’ has become an all too familiar chronic state of being for many of us. Designed to kick in when experiencing danger (fleeing a tiger for example), it fires up stress hormones like cortisol, making us hyper-alert, ready to save our skins by fleeing or fighting. This is a useful mechanism and obviously a completely necessary one when considering the importance of our ultimate survival. However, the many stressors or perceived stressors we face in our modern lives turn this acute state of being into a chronic one, leaving us in a continuous state of stress. The impact of this on our overall health is huge, leading to increased risk of acute and chronic illness.
The enteric nervous system operates in our gut. It is finely tuned with the rest of our nervous system receiving input from the parasympathetic and sympathetic nervous systems. However, it plays by its own rules. This autonomy gives it the nickname ‘our second brain’, and it is responsible for decreasing any of the stressful responses we may be experiencing. During the COVID-19 pandemic, many of us experienced a heightened state of fear, stress and anxiety; a sympathetic nervous system dominant state, driving inflammation. These are common symptoms I see in clinic. Therefore, we are often looking at ways to stimulate the vagus nerve and increasing vagal tone. Vagal stimulation is essential, and is a cheap, easy way to help restore a parasympathetic state of being. These are some of the things that stimulate the vagus nerve and can be incorporated into our daily lives:
breath work: slow down your breath, breathe through your nose and exhale longer than you inhale. Just three slow nasal breaths can reset your parasympathetic nervous system;
singing and humming;
gargling with water will stimulate our vocal cords and in turn our vagus nerve;
meditation, yoga and mindfulness;
cold water therapy swimming or showering, even just dunking your head in cold water;
chewing food slowly and on one side;
eating bitter foods (also good for the liver);
getting out in nature, into green spaces, the Japanese practice of ‘Shinrin yoku’.
Now you can see why the vagus nerve commands such celebrity status. If you are interested in any of the above, here are a few ideas you may want to explore further.
Wim Hof aka ‘The Ice Man’ - known for extreme cold-water submersion and breath work: www.wimhofmethod.com
Mindfulness - Ruby Wax has written a couple of highly accessible books on the subject: - ‘A Mindfulness Guide for the Frazzled’ - ‘Sane New World: Taming the Mind’ - ‘A Mindfulness Guide for Survival Breathing’.
James Nestor’s book, ‘Breath’ is a fascinating read and reminds and enlightens us about how breath and mind are interconnected.
'Forest bathing' is a Japanese practice of relaxation by spending quiet reflective time in woodland, to find out more visit www.forestryengland.uk/blog/forest-bathing.