The vagus nerve is a very long nerve that carries signals back and forth to your brain, heart, lungs and digestive system. It is the longest cranial nerve in your body. It is said to run from the brain all the way to the large intestines. It also has branches that reach all of our major organs.
I tell clients that the vagus nerve is what people consider to be the “lizard brain” of the body. It is responsible for fight or flight responses and also freeze and hide. It controls involuntary sensory and motor functions like your heart rate, speech, mood and urine output. It is a very complex system of communication with our entire body but it has a very important role in how we respond to stress. The role it plays is regulating the way the body switches from the rational brain (the parasympathetic nervous system – relaxed state) to a fight or flight response (sympathetic nervous system – alert state).
Apparently the vagus nerve can lose its ability to switch back easily to the parasympathetic mode due to factors like stress or age. Also Known as vagal dysfunction, this can put a person at risk for high blood pressure, heart disease, Type 2 diabetes, depression and anxiety.
Professionals say that stimulating the vagus nerve will help our body to switch more quickly to a relaxed state. They recommend a variety of things to do to “stimulate” the vagus nerve. These include: 1) meditation, 2) exercise, 3) music, 4)massage, 5)cold exposure and also through 6) a medical intervention, applying an implanted or transcutaneous vagus nerve stimulation, VNS/tVNSSo “stimulation”.
These activities create a cascade of events in our body that lead to activating the parasympathetic nervous system. Sensory signals initiate when we participate in one of the above activities. This signal then travels up to the brain stem from the lower part of the body that is participating in the activity/sensation. The brain stem then sends signals to activate certain parts of the parasympathetic nervous system, which in turn, decreases cortisol, heart rate, and increases metabolism. This mechanism triggers the release of chemicals like serotonin and anti-inflammatory related chemicals that help our body feel calm and less pain. This series of events isn’t just for experiencing relaxation — it’s a multi-system communication event linking the nervous, endocrine, and immune systems. It affects not just an emotional state but the entire body.
The reason that the above activities trigger a response that activates the parasympathetic nervous system is the need for our body to seek balance and recovery. When we shock it with cold our body wants homeostasis, so it activates a series of events to calm us down. This idea of trying to return back to its original state and achieve homeostasis is also at work with activities like massage/yoga/exercise. These activities create specific changes in our body systems that makes the body want to return to it’s original state. Our body registers the sensations and our vagus nerve sends out messages to release chemicals to balance excitement or other changes. These chemicals make us feel calm and “okay”. Breathing/humming/music can also do the same thing. Basically any sensory activity that is not overly stressful or perceived as actual danger, can stimulate the vagus nerve in a healthy manner. The more we do these activities, the more training we do for our system to be stronger and recover quickly from changes and imbalances, ie stress in our environment.
On a side note, a big chemical messenger that is responsible in this process is Acetylcholine (Ach). It’s a little bit more technical for me to explain so for further information on this process, go to this link.
Also for more info on polyvagal theory, click here.
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