What Triggers ANS Fainting?

Syncope, or fainting, is one of the common symptoms in autonomic dysfunction, a disorder in autonomic nervous system, also called ANS. This type of syncope is called Neurocardiogenic syncope, or neurally mediated syncope (NMS).

The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, urination, and sexual arousal. Most of these actions are involuntary, but some, such as breathing, can also be done consciously.

There will be a drop in blood pressure and the heartbeat and pulse rate will slow down. This causes a temporary interruption in the brain’s blood and oxygen supply.

Possible triggers include:

  • suddenly seeing something that is unpleasant or shocking, such as blood
  • suddenly exposure to an unpleasant sight or experience
  • sudden emotional upset, for example when receiving bad news
  • extreme embarrassment
  • standing still for a long time
  • being in a hot and stuffy place for a long time
* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.