system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do babies in the womb not get head rushes even though they are suspended upside down?
gpt
The head rush comes from how much pressure is exerted by gravity pulling all that blood into your head. The amount of pressure the blood exerts is proportional to the weight of the blood that’s directly over your height; which is proportional to your height. Babies are really short, so not a lot of blood directly overhead, so not a lot of pressure, so no (or very little) head rush.