Board Thread:General Discussion/@comment-31371445-20170222233857/@comment-27136653-20180813195219

As I said above,

(B) HP represents the connections between the soul and the body, all identical and parallel to each other. You will have a harder time communicating with your soul if you have less connections (more current forced to move through the same wire), but you will die only if the connection count reaches 0. In essence, the HP is not the hit points of the soul, but of the thing keeping the body alive.

Also, this HP is still magical. It's the connection between the body and the soul, not literally the stamina of the body. This is how Frisk doesn't get physically damaged much, and it also explains how could the souls of the other humans persist, assuming the mosters attacked them the same way they attacked Frisk.