In a previous article, I explained the difference between the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). These two systems are the two main divisions of the autonomic nervous system (ANS) and both have an enormous effect on our well-being. Together with the HPA axis, they play a big role in our stress response. And they can either trigger your fight or flight response or help you transition back to the rest and digest response. An imbalanced nervous system can be disastrous, but luckily there are some PSNS-activating techniques at your disposal to calm down an overactive SNS and restore homeostasis.
As you can imagine, knowing how to stimulate the rest and digest response at will offers tremendous benefits. It helps you to be in charge of your own well-being again, even in times of enormous stress. To help you regain this control, I share some of the most effective methods in this article.
What are the SNS and PSNS?
The sympathetic nervous system and the parasympathetic nervous system are the two main divisions of the autonomic nervous system (ANS). They are activated in times of arousal and recovery, respectively.
The best way to explain the difference between the two, is by looking at their nicknames.
The SNS is often called the fight or flight system, whereas the PSNS goes by the name the rest and digest system. In other words, SNS activation helps your body prepare for a perceived threat, and PSNS activation helps you calm down afterward.
For more information on the two systems: Differences between the Sympathetic and Parasympathetic Nervous System >>
Why is a balanced nervous system important?
When our nervous system is imbalanced, our body is not offered the chance to recover. Although we speak of “activation”, in reality, both the SNS and PSNS are always operational. Your body is constantly trying to restore homeostasis and the yin and yang pull of these two systems helps to maintain this balance. But the more time we spend in PSNS the healthier and more relaxed we will be.
The triggering of the fight or flight response leads to several physiological changes. Your pupil size increases, your heart starts beating faster, and a cascade of stress hormones like epinephrine (adrenaline) and norepinephrine (noradrenaline) is set in motion.
Ever noticed how much faster your heart starts beating after a frightening jumpscare? You have your SNS to thank for that.
Of course, this cannot go on forever. and once the stressor has passed it is the PSNS’s time to shine. Its functions are mostly mirror opposites of the SNS’s effects.
Once the scary part is over, you have probably also noticed how your heart rate slowly goes back to normal? That is your PSNS doing its job.
However, besides restoring homeostasis, your PSNS is also in charge of maintaining it. It is the default setting when you are not in danger or stressed. And it is only in this state of relaxation, that your body can recover.
How to reset your nervous system?
You can reset your nervous system with the following PSNS-activating techniques:
- Smile and have fun
Having fun is an incredible stress-relieving method. It sounds simple, but we really do not practice it enough.
Furthermore, when we are having fun, we tend to smile, which in turn causes the brain to release neuropeptides. Neuropeptides are tiny molecules that are designed to fend off stress and help facilitate communication between neurons. Besides these neuropeptides, the typical feel-good neurotransmitters (dopamine, endorphins and serotonin) are also released into the bloodstream.
- Sound healing
Sound therapy can alter your brain waves and induce the brain’s relaxation response by activating the PSNS through the vagus nerve.
The vagus nerve is the most influential cranial nerve in your PSNS and the longest one in the body. Its many branches create a path from the brain to all the organs in the chest and abdomen. This explains where its name comes from as the word vagus means “wandering” in Latin.
Because of its extensive distribution in the body, it comes as no surprise that this “wandering” nerve is in charge of several bodily functions, such as heart rate, respiration, and digestion. Of its many branches, the vagus nerve has one that goes to the tympanic membrane, or eardrum. This is a tin layer of tissue in your ear that vibrates in response to external sounds. And listening to the right sound frequencies can be incredibly calming thanks to this auditory stimulation of the vagus nerve.
- Diaphragmatic breathing
Are you a chest breather or a belly breather? It seems like such an automatic thing, but many of us have, unfortunately, never learned the art of breathing. We rely on chest breathing instead of belly breathing and are breathing incorrectly.
What is the difference between the two?
- Chest breathing is also called shallow breathing. It consists of drawing in shallow breaths through your chest, which means a large amount of oxygen fails to reach the lower lung.
- Belly breathing is also called deep or diaphragmatic breathing. It consists of taking deep breaths through your lower abdomen and diaphragm. The air is pulled in and out of your lungs, but your chest and shoulder blades barely move.
Diaphragmatic breathing, or slow abdominal breathing, forms part of pranayama, the fourth "limb" of the eight limbs of Ashtanga Yoga. Prana is a Sanskrit word that means “life force” and ayama means “extending” or “stretching”. In other words, by learning how to breathe properly, you can extend your breath, or life force, to every cell in your body.
Furthermore, each time you take a slow, controlled, diaphragmatic breath, specific neurons that detect blood pressure are activated. These neurons signal to your wandering nerve that your blood pressure is rising, and the vagus nerve in turn responds by lowering your heart rate. Diaphragmatic breathing thus helps you to relax by stimulating the vagus nerve, indirectly and instantly.
Other methods to hack and reset your nervous system
- Mindfulness and meditation
The SNS and PSNS play a big role in your stress response, and they can either trigger your fight or flight response or help you transition back to the rest and digest response.
Understanding the difference between the two allows you to purposely stimulate your PSNS and restore homeostasis.
article by Eline Stone