Why do people faint when they’ve had a shock or scare?


Is there something in their brain that gets overloaded or something?

In: Biology

Women used to do it more because the corsets they were wearing a restricted their breathing so much. So any time the wearer exerted themselves or had a shock they fainted from lack of oxygen. It can still happen today, but it happens much less frequently because we do not dress like that anymore and can breath more easily.

It’s actually the opposite.

Your sympathetic system is this “fight or flight response”, which increases your blood pressure when you are very shocked or scared.

After the scare has passed, your parasympathetic nervous system tries to calm the body down by lowering the blood pressure.

However, when blood pressure changes too quickly (BP drops), not enough oxygen is delivered to the brain quickly enough and it starts to shut down.

From my understanding, your brain thinks it’s something that your body is in danger from, so your brain shuts your body down momentarily to prevent you from doing whatever it is that might hurt you. Like if you see blood, your brain may think you are bleeding, so to reduce your heart rate and slow bleeding down (even if it’s not you bleeding), it’ll knock you out to do so. It’s also why you can’t hold your breath till you die, your brain will shut you down to let it take over and reset everything to favorable conditions, making you breath again.