The main culprit behind these fainting spells is anxiety, which causes a dramatic fluctuation in blood pressure.

Initially, there's a spike in blood pressure, typical of a stress response, but then it sharply drops.

This sudden decrease causes blood to flow away from the brain, resulting in loss of consciousness.

Normally, an increase in blood pressure is a part of our instinctive "fight or flight" reaction to perceived danger.

The problem arises when this reaction overcompensates and then reverses too quickly. This is where the vagus nerve comes into play, linking the brain's nucleus of the solitary tract (NST) to parts that control involuntary actions, including heart rate and breathing.

The NST is like a switch that can flip between the high-alert state of "fight or flight" and a calmer, restorative mode.

Imagine an orchestra trying to play a fast-paced and a slow tune at the same time.

The vagus nerve, acting as the conductor, tries to manage both, resulting in a mixed signal – reducing blood pressure while increasing heart rate. The outcome is a 'fainting orchestra', as blood rapidly leaves the brain.

There's also a theory suggesting the NST switches modes too quickly, leading to a temporary system shutdown. Complicating matters is the disgust response, which the NST also regulates. But why does this confusion occur? One hypothesis is that it might be a primitive survival tactic.

Consider our ancestors: feigning death upon seeing their own blood might have deterred predators.

Imagine encountering a bear, fainting, and the bear losing interest – you survive another day. This scenario is akin to the behavior of fainting goats.

A more plausible theory is that fainting acts as a protective mechanism, potentially preventing further blood loss.

When someone faints, their horizontal position helps to restore blood flow to the brain. By the time they wake up, the situation that caused the bleeding may have been resolved or lessened.

So, if you feel faint at the sight of blood, it might be an odd yet effective survival response, keeping you safe – and far away from metaphorical bears.