I'm completely guessing here, but are you trying to make your monsters stronger? Look in my sig for my "hardcore channels" release as it does exactly that.
Hmm i guess he want to stop mobs from regenerating hp when they are not in a fight... well you can`t do that, unless you got the source codes and you code it!
Well there is the HPRechagR column in mobs.scp and i know it controls the HP recharge rate but i can't remember if that is when in combat with the mob or all the time. Try reducing it to 0 and test.