If you are like me, you certainly want a scientific explanation for how things work. After years of having read up on the benefits of yoga, I am convinced that our brain is nurtured by yoga, as the rest of our body. Nevertheless, I could not help getting excited when I read scientific explanations of “Why yoga works”. I recently came across an article by Dr.Angela Wilson, a Kripalu Yoga center faculty member, about how yoga nourishes the Vagus nerve, a key factor in our mental and physical health. The Vagus nerve is the longest nerve in the body (actually it’s a pair of nerves) and travels from the base of the skull downward, connecting with all the organs below. It is the lifeline of nervous impulses.
In this blog I am sharing that exciting information with my readers to give you a bird’s eye view of the power of the Vagus nerve and how yoga can be used to activate it. I am not a physiologist and therefore my explanation is rudimentary and commonsensical. For those of you who want more detail, I have provided a link to Dr. Wilson’s article, below .
Vagus means “wandering” in Latin. This nerve connects with the brain at the base of the skull and the meanders all over the body connecting to all the key organs of the body (see figure below). It is like a river that nourishes various cities with its water, feeding the flora and fauna wherever it flows. Blockage anywhere collects debris or results in an overflow – both of which are harmful. Similarly, when nourished, the Vagus nerve is the primary transmitter of nervous impulses which keeps the body active and energized. Hence it is known as a superconductor as it controls the motor and sensory neurons that connect the brain, ears, heart, lungs, tongue, esophagus, stomach, intestines, liver, pancreas, gallbladder, kidney, ureter and female fertility organs! An undernourished or weak Vagus nerve can lead to several ailments caused primarily by inflammation of these organs. The Vagus nerve is also responsible for the voluntary muscles that control speech and expression. Darwin called it the nerve of emotion. It is also associated with digestion and relaxation of the GI tract. In short it is a powerhouse of nervous impulses.
The Vagus nerve has four primary functions –
 Parasympathetic: Responsible for the operation of the digestive tract, heart rate, and respiration.
 Special sensory: Provides the sensations of taste from behind the back of the tongue.
 Sensory: Operating specific mechanisms of the abdomen, heart, lung, and throat.
 Motor: Enabling the movement of neck muscles, enabling speech and swallowing.
The Vagus nerve is responsible for the Parasympathetic nervous system functions. I can see you go Aha! It promotes the rest and digest functions, especially the digestive, immune and respiratory systems. It helps to balance out the flight or fight responses triggered by the Sympathetic nervous system. A very effective way to nourish it is through the breath. Deep breathing practices with slow and long breaths activate the PNS, which in turn sends the body into rest and digest mode. It is in this mode that the body recovers and rejuvenates from the stresses caused by the Sympathetic nervous system. In the Fight or flight mode body is geared for action necessary to address physical or mental threats, requiring it to be alert and at work. Breath regulation whether it is during Asana(pose), Pranayama (breathing practices) or meditation induces relaxation – both physical and mental. This activity reduces the symptoms of anxiety, fear, and stress.
There is also enough evidence that slow breath reduces the heart rate which is necessary for arresting inflammation. Inflammation is the primary cause of many illnesses. A well-functioning Vagus nerve prevents inflammation and even serves to reduce existing inflammation. Multiple research studies have proved that many mental illnesses can be treated by contemplative practices because breath control slows or even hampers the advance of inflammation, alleviating the symptoms of medical conditions such as arthritis, depression, epilepsy, inflammatory bowel disease (IBD), migraine headaches and others.
What makes this information more fascinating is the theory that the chakras or metaphysical energy centers lie along the spine. These energy centers are fueled by the nervous impulses of the Vagus nerve. Read more on the connection between the chakras and the Vagus nerve by following the link below.
Need I say any more?
The breath is key to an effective yoga practice, whether you are holding a pose during which time you are focusing on your body and breath or doing pranayama or yogic breathing techniques or meditating. Yoga promotes mindfulness no matter which practice you are following. The act of mindfulness calms the PNS.
Very simply , people with high vagal tone or where the vagus is nourished and functioning optimally are well adjusted and recover quickly from stress. Needless to say, those with low vagal tone will be harder hit by stress and will take a longer time to recover. Looking at this from the perspective of psychology, people who are SNS dominant or who get into the fight or flight mode easily and take longer to recover and will be more susceptible to mental illness – be it PTSD, Anxiety, Depression. Oftentimes the stress response leaves a residual in these people and the next stress incident adds on to this load. It goes on until there is a situation which finally breaks the camels back. That is when the individual has a complete breakdown. This is a simplistic explanation. It is sufficient to help us understand what happens to our body because of continuous stress when our nervous system is weak and vulnerable. There are both physical and mental repercussions. It therefore critical that we keep our CNS nurtured by natural methods. Yoga is the key here.
I know of people who have cured themselves of various ailments including cancer and auto immune diseases by consistent and prolonged practice of Yoga, primarily pranayama and meditation. I am now convinced that anyone can take charge of their health by a deep and wholehearted pursuit of yoga. I used the term wholehearted because I have know several people who practice yoga for a few weeks and give up because they do not see miracles happening or there are those who have been practicing yoga for years but are still anxious and stressed out. Yoga is not a short-term cure. Its benefits are displayed incrementally and not miraculously. Committed practice will slowly chip away at the accumulated debris from stress and eventually detox the body and the mind. The outcome will be a happier and healthier person who takes stresses in stride. This does not mean that they are not affected by stress at all. It means that they manage stressful situations better and recover completely from the aftereffects.