I wasn't thinking of "converting" 5E to this- but rather an (imaginary) new edition of D&D that would utilize the concept. And obviously there would have to be some tweaks/rules so players wouldn't game the system.
I would indeed say you should burn your attribute scores and recovering them requires a doctor/cleric or extensive rest. That way there's no need need for another resource in the game. I'm inclined to say this might work better if you merge strength and constitution into a single body attribute, though.Or maybe you burn CON points to roll death saves/last gasp spells/actions and getting them back is not easily done.