March 25th, 2020
What is the autonomic nervous system and how can you activate it to bring about homeostasis and healing? There are hundreds of ways to do this – I can share some of these with you.
The autonomic nervous system is, in neuroscience, frequently referred to as the involuntary nervous system.
The voluntary nervous system allows us to move our hands, legs and perform self-directed actions like speaking, running, moving etc. using conscious will. It is controlled by the motor cortex in the brain. The motor cortex for right handers is on the left side and on the right for left-handed people.
The autonomic, involuntary system – it can be controlled to a degree so it’s not an entirely involuntary system as I will show – in most people behaves in a consciously uncontrolled way.
The involuntary system is a division of our peripheral nervous system which is beyond the cortex of the brain supplying nerves to various parts of the body including the smooth muscles. These are the muscles in our viscera influencing the internal organs of our body.
It acts largely unconsciously and regulates bodily functions such as heart rate and digestion, respiratory rate, pupil response in the eye, urination etc. Within the brain this system is regulated by parts of the limbic system; the hypothalamus, the pituitary and many other systems which connect our emotions to our bodily function.
The autonomic system is thought to have three divisions. The sympathetic nervous system is responsible for the fight or flight response, which acts under threat, resulting in high blood pressure, speeding up of the heart, sweating, shutting down of digestion and diverting blood to the muscles of the extremities – fight, flight or freeze response. This is very useful in certain situations but if we perceive threat all the time, even a persistent, low grade perception of threat, or indeed more, as is happening right now, we go into sympathetic overdrive which raises the blood pressure etc. and brings about inflammation, raises cortisol levels which suppress immune function, raises adrenal levels in the circulation causing inflammation in the body. In general this sympathetic nervous system overdrive weakens our immune system, making us more susceptible to disease.
The second part of the autonomic system is called the parasympathetic nervous system. Predominantly the most important nerve in this system is the vagus nerve. It has branches to all the organs of our body.
In yogic tradition it is felt to be a healing nerve.
The parasympathetic nervous system gets activated when we are in deep relaxation and through various helpful breathing techniques and is responsible for decreasing activity in our body and giving us more resilience and flexibility. If the parasympathetic nervous system is activated you decrease inflammation, enable heart rate variability, you increase the depth of your breathing, breathing rate slows down and homeostasis and self-regulation kick in.
The highest activation of the parasympathetic nervous system occurs with deepening of the breath and also stillness in the mind.
The experiences we have are sensations, images, feelings, thoughts (interpretation of sensations) and sense perceptions. These are entangled, they all influence each other. They also influence our autonomic nervous system.
If you want to immediately activate the parasympathetic system you need to quieten the mind. The quiet mind is the healing mind. You need to deepen the breathing and there are other techniques too.
The third part of the autonomic nervous system which is being talked about now – it is referred to as the enteric nervous system – the nervous system which is present in your gut, your digestive system and your colon etc. It is part of our visceral system and influenced by the microbiome i.e. the bacterial genes that live in our gut. These genes are very influenced by diet and emotions.
Your diet can influence the activity of your autonomic nervous system, can cause inflammation and also trigger the healing response mentioned earlier by shifting the microbiome from being inflammatory to non-inflammatory.
So, even though the autonomic nervous system is beyond our awareness mostly it is influenced by our emotions. Emotions can trigger the healing response or immunal compromise.
The simplest way to activate the parasympathetic nervous system , the vegus nerve, self-regulation and healing response activation through breathing is often called the yogic breath. An easy form of pranayama, as it is called, involves lying on the floor or a mat.
Lie down and relax your body with your hands slightly away from your sides. Allow yourself to be comfortable. The right hand goes on the abdomen just above the naval, and the left hand over the centre of the chest. Observe your natural breath.
Now focus on abdominal breathing. Breathe through the nose. Feel as though you are drawing the energy and breath in and out through the naval. The right hand will move up with inhalation and down with exhalation. The left hand remains almost still. Do not expand the chest. Inhale whilst expanding the abdomen comfortably without expanding the rib-cage much. At the end of the inhalation the diaphragm will be compressing the abdomen and the naval will be expanded upward. At the end of the exhalation the abdomen will be contracted and the naval will be compressed downward toward the spine.
Do this for a few minutes. Afterwards bring the awareness to the physical body as a whole and then to your surroundings before gently rolling over to rest and gently sitting up.
This will have activated your parasympathetic nervous system and invoked the calm response which will strengthen your immune system.
Yoga and meditation are both key practices for health at all times but particularly now in the Covid-19 pandemic.