Why does pain cause one to feel dizzy?

Question

for example, when I got bad diarrhea or period cramps, I start feeling lightheaded and like im going to faint. It also clogs my ability to think and I have to take a while to recall certain things

In: 37

Answer 1

Bearing down like when you have a bowel movement (specifically, exhaling against a closed glottis) can stimulate the vagus nerve, which can cause your blood pressure to drop. It’s called a “Valsalva maneuver”. It has certain medical applications.

Otherwise, pain or emotional distress (e.g. seeing something traumatic) can cause a vasovagal response. Same idea — vagus nerve is stimulated, blood pressure drops. The feeling of lightheadedness and possibly fainting (syncope) can sometimes occur depending on the severity of the reaction.