Stress and anxiety are the two biggest hurdles to taking your health to the next level. Constant high cortisol states can have negative impacts on virtually every organ system in our bodies. Calming down that sympathetic nervous system, or "fight or flight" response, and allowing our bodies to rest and re-coop is essential to overcoming chronic disease. The vagus nerve plays a HUGE role in our ability to RELAX...
WHAT IS THE VAGUS NERVE?
The vagus nerve, also known as nerve X, is the 10th cranial nerve or set of nerves. It is the main set of nerves of our parasympathetic nervous system - your rest and digest and relaxation. Vagus is latin for wandering, which is appropriate for this set of nerves as they sort of wander throughout our bodies. These nerves exit from the medulla oblongata in the lower brainstem and connect with our neck, chest, heart, lungs and abdomen. This set of nerves controls involuntary functions of our bodies such as heart rate, blood pressure, digestion, immune system regulation, skin and muscle sensations, taste, urine output, coughing, sneezing, swallowing, vomiting, and plays a role in mood. The most important function of the vagus nerve is to bring information from the inner organs like the gut, liver, heart, and lungs to the brain. These organs then are constantly giving information to the brain with the gut being the largest (Breit, S).
VAGUS NERVE AND YOUR MOOD
How do the vagal nerves affect your mood? I am going to try to paint this picture in a way that is easy to understand...periods of high stress are inevitable and our bodies know how to respond to this stress by diverting our rest and digest and relaxation to pumping out cortisol so we can survive. Sort of like running from a hungry, vicous tiger as they did back in the cave man period. It's when a person is under constant, long period stress i.e. running a from tiger for too long due to work, family stressors, and not sleeping etc that the vagus nerve essentially becomes like a faulty electrical wire and misfires. This misfiring decreasing vagal input to areas like the heart, lungs, neck, and gastrointestinal tract leading to symptoms of decreased vagal tone and high cortisol i.e. shallow breathing, rapid heart rate, insomnia, bloating, frequent illness, and brain fog.
THE GUT AS A KEY PLAYER
Inside our guts is something called the enterohepatic nervous system (ENS). The ENS produces more than 30 neurotransmitters and has more neurons than the spine (Carabotti, M). The ENS, combined with the parasympathetic and sympathetic nervous systems, allows for bidirectional communication between the brain and the gut AKA the brain-gut axis. The ENS has similar structure and function to that of the brain and has been called the "second brain" or the "brain within the gut" (Goldstein A). The ENS in the small and large bowel regulates bowel motility, mucosal blood flow and barrier function, regulates the innate and adaptive immune systems and detects nutrients in the gastrointestinal tract. Cell loss in the ENS is associated with symptoms like constipation. The total loss of the ENS could be life threatening, but the loss of vagal tone in this area is not life threatening although it is undesirable due to side effects.
HOW THE VAGAL NERVE CONNECTS THE BRAIN TO THE GUT AND WHY THIS IS IMPORTANT