Random vagus nerve facts!
This is a bit of a random post, but it illustrates just how powerful the vagus nerve can be in health!!
My previous post talked about what the vagus nerve is, and how it affects almost every part of the body,
In medical school and hospital medicine, my main knowledge of the vagus nerve was around stimulating it to stop arrthymias (irregular heart rhythm), it's role in vasovagals ( fainting), and how it can complicate surgery on the eyes and the cervix
In some heart arrthymias we use vagal nerve stimulation to try revert the heart to a normal rhythm (mostly in SVT or supra ventricular tachycardia - where the heart short circuits and starts to beat very fast). To do this we'd get people to hold their breath (valsalva) , or would splash cold water on the face /back of the neck - you can see how the heart slows down temporarily, it's pretty cool!!
I also have vivid memories of anaesthetic drs nervously watching the ecg (heart tracing) during eye surgery - the oculocardiac reflex is a weird thing where pressure on the eye stimulates the vagus nerve and can even stop the heart in severe cases - fortunately it's very rare thanks to precautionary measures
The female cervix has strong connections to the vagus nerve - procedures that stimulate the cervix can trigger a major vagal reaction where the heart slows down and people faint - something most doctors will have seen (and never forget)
And even straining too hard to pass a bowel motion can cause a vasovagal (faint) due to pressure on the diaphragm muscles increasing vagal tone. There is a condition called commode cardiac which means sudden cardiac death while sitting on the toilet, which is thought to be due to this (again incredibly rare! )
Vagus nerve stimulation is used for treatment of certain medical conditions including epilepsy and severe depression, and is being trialled to treat rheumatoid arthritis, inflammatory bowel disease, alzheimers, headache, and even obesity
Some studies in humans have shown that people with certain gut disorders (irritable bowel syndrome and inflammatory bowel disease) have reduced vagal tone, suggesting improving this may help to treat it
Gut directed hypnosis has been shown to be as effective as dietary changes in treating IBS, again showing the power of the mind body connection
Our gut bacteria seem to impact on the vagus nerve as well -certain bacterial species in mice alter stress hormone levels, and when the vagus nerve is cut, this effect disappears. We dont know how much of an effect this has on humans as trials are limited, but altered gut biome has been shown to affect mood and inflammation
All of this goes to show just how much impact the vagus nerve can have on health - and why improving vagal nerve function can have such massive benefits!
Its at the very root of the mind body connection