woman with face in her hands

The Autonomic Nervous System (Sympathetic and Parasympathetic)

Your autonomic nervous system plays a crucial role in keeping your body moving. It is the reason we automatically carry out vital functions such as breathing and digestion, it keeps our heart beating and carries out various other operations that we may not even notice. The autonomic nervous system is further divided into two branches: the sympathetic and parasympathetic. Each branch denotes different involuntary behaviours involved with the fight or flight response.

Our fight or flight response is triggered when we are faced with an event that is stressful, frightening or dangerous. It is an immediate physiological reaction that involves many parts of your body with the intention of readying you to either fight the threat or flee from it. The response was an essential tool for survival for our ancestors, back when they needed to navigate the wild. In modern times, the need to fight or flee a situation is less common, but the ancient physiological instinct still remains and can be triggered during stressful life events, even if there is no actual physical threat present.

Sympathetic Nervous System

The sympathetic nervous system is the system that is triggered when you are faced with a perceived threat. For example, if you suddenly hear a loud, unexpected noise you may ‘jump’ in response. This is your sympathetic nervous system being triggered.

In order to best help you in a threatening situation, your sympathetic nervous system will slow down the less essential autonomous bodily functions – such as digestion – in favour of the functions needed to fight away a threat – such as an increase in heart rate.

The following symptoms are experienced during an acute sympathetic nervous system response:

  • Pupils dilate
  • Salivation is inhibited
  • Heart rate increases
  • Bronchi dilates
  • Digestion is inhibited
  • Contraction of bladder is inhibited
  • Increased sweating

These symptoms are exhibited when you experience anxiety. In fact, anxiety is simply your sympathetic nervous system being triggered. At times this can be a helpful response, but at other times the experience is highly unpleasant and overwhelming. When a sympathetic nervous system response continues to occur despite no threat being present this can be considered an anxiety disorder.

Parasympathetic Nervous System

The other key part of the autonomic nervous system, our parasympathetic nervous system acts in direct response to the triggering of the sympathetic response. Once the perceived threat has passed, your parasympathetic system steps in to help return your body to its normal, resting state. Without it, your body would stay locked in that heightened place, unable to calm down.

The symptoms associated with the parasympathetic nervous system are:

  • Pupils constrict
  • Salivation is stimulated
  • Heart rate slows
  • Bronchi constricts
  • Digestion is stimulated
  • Bladder contracts
  • Sweating decreases

The parasympathetic nervous system works to restore balance within your body. When the parasympathetic nervous system is unable to effectively regulate the body’s functions, this can result in disorders such as chronic stress and anxiety disorders. When both the sympathetic and parasympathetic systems cannot work in tandem with one another to response appropriately to life’s events, the autonomic nervous system is thrown out of balance and can cause long term problems.

Share this post