of course what vicvega is saying is grenades give you the combat xp and bleeds give xp to what every form of attack happens after the bleed ( think of bleeds as O type blood, they work for everyone , LOL)
health shot1 (you should have this one by now) and health shot2 bleed the HEALTH pool, there are others for the mind and action pools, but i dont use them so i dont remember their exact names.