It really depends on the type of shock but say anaphylaxis causes blood vessels to dilate, resulting in lower blood pressure. A lower blood pressure will eventually lead to not enough blood reaching vital organs in time which is bad for you.

Shock is a medical term used to describe any hindrance of regular blood flow. It's not the same as being 'shocked', like if something traumatic happened to you.

[–] LadyButterfly@piefed.blahaj.zone 3 points 2 days ago (1 children)

OK so it's like the blood is going more slowly? So does shock only happen when someone has a problem with their blood?

[–] Bigfish@lemmynsfw.com 7 points 2 days ago

Not slowly per se. More like not enough to go around. Heart rates spike when blood pressure drops to try to move the lower volume around faster, but even that emergency autonomic response can lead to other problems.

Does it only happen with problems with blood (like bleeding): no. Other responses to trauma, both physical and mental, can lead to a person's body pushing blood to the surface muscles, which can deprive the vital things like organs and brains of sufficient blood. In normal cases this is just fight or flight systems kicking on. More blood to muscles is good there. But it can go too far and lead to these problems. Bodies overcorrect all the time - think dangerous fevers, or dangerous allergic reactions.