There's a number of tabletop RPGs that use the double of your health points to determine how close you are to actual dying or something similar.  I remember a case in D&D where our sorceror was currently a polymorphed sheep with an exploding potion strapped to him as he was tossed at a very strong assailant as a projectile.  There was a large chance of him being mulch in the aftermath, but he was like 4 HP shy of double his full health count, so he was considered very thrashed, but recoverable.