The Vagus Nerve

This week I'm delving back into our mental health and talking you through some of the specifics of the vagus nerve. I have posted about this nerve on instagram before and even made a little info graph to showcase some of it's functions - but there are oh so many and I thought it was deserving of it's own space over here on the website. With that thought, please note I am still going to be focussing in on the digestive and mental health related functions -  and how you may be able to use this knowledge to look and feel your best self.

This post is divided up into the what (some anatomy and physiology of the nerve), the why (functions) and the how (literally how you can stimulate this nerve and use it to your advantage !)

The Vagus Nerve - Structure:

The vagus nerve or cranial nerve X runs all the way from your brain (extending through your brainstem) down your neck and through to your abdomen. Within the neck the nerve is responsible for functions such as vocalisation and swallowing. Down in your chest, the nerve sends parasympathetic signals to your heart (your parasympathetic nervous system is the one responsible for your 'rest and digest' functions, and in this case slows your heart rate). From the chest it continues down into your abdominal area - where your digestive organs are located. It wanders from your stomach, to small intestines, liver and pancreas.

 Functions:

The vagus nerve is essentially responsible for most of your parasympathetic nervous system (again, your rest and digest - opposite to your fight or flight responses). The primary role of the nerve within these reactions is to bring information from the organs it runs through; to your brain.

Focussing in on digestive health, the vagus nerve forms part of what is known as the gut - brain axis. Essentially there are a large amount of neurons (nerve cells) within your gut; it is estimated that there are around 100 - 500 million neurons here - which is actually the largest group in your body ! For this reason your gut is often described as the 'second brain' and is known as the Enteric nervous system.

In regards to your gut - brain axis this is part of the anatomy ( the neurons in your gut contacting the vagus nerve which lead up to your Central nervous system ) This connection allows for two way communication between your brain and digestive system. This axis is responsible for connecting cognitive and emotional areas of the brain with a number of intestinal functions, as well as for monitoring the balance or homeostasis of these (for example immune function, intestinal permeability).

The gut brain axis encompasses the brain, spinal cord, hypothalamic pituitary adrenal (HPA) axis, and the autonomic nervous system (which includes sympathetic, parasympathetic and enteric nervous system)

Your brain sends messages down to your gut along this axis (however only 10 - 20% of messages are going this way). Most of the communication is actually going up from your gut to your brain ! This pathway is involved in the activation and regulation of your  HPA axis - which is essentially responsible for how your body reacts to stress.

 Your gut's microbiome (which I have discussed over on this article) plays an important role in regards to influencing the cells within the gut (which are communicated to via by the gut - brain axis ) for example your smooth muscle cells, epithelial cells (skin) the enteric neurons and even your immune cells ! You want to keep your gut microbiome in a healthy state in order for this communication to be positive.

Stimulating the Vagus Nerve:

Stimulation of this nerve may be useful for a number of conditions, including helping to ease anxiety, depression, even epilepsy and general digestion - why ? Stimulation of this pathway is helping to activate your parasympathetic nervous system ( the rest and digest ) so quite literally helps you to calm down and switch out of fight or flight mode - which most humans find themselves in a lot of the time. How can you simulate this nerve? Remember it begins in the brain and travels all the way down through your throat and into the abdomen. Certain things you do anyway may actually be activating this pathway - such as singing, gargling, humming. You can intentionally activate it by doing big deep belly breaths (look up the Wim Hoff method if you have't heard of it already), also cold showers / swims. 

That's it for today - I hope you found this post insightful and hopefully also useful ! If you did be sure to share with your friends and family and leave a comment :)