How do I heal outside of battle in Hunted: The Demon's Forge?

I may have missed this part during the tutorial and now I can't figure out how to use a potion outside of battle. I'm usually at pretty low health after a fight (I favor melee to ranged) so I'm dying at the very beginning of the next enemy encounter.

Is there a button to heal outside of battle? Also, do I have to wait for my partner to heal me during combat or can I do it myself?

Using health potions is done by R key,worked for me no matter the combat status.Plus the health potion capacity and health points are increases by overall kills(you+partner).

Restoration potions(potions around players waist) can only be used to revive other player,done by space.After you have revived or been revived enough times the capacity of the bottle increases to maximum of 3 (11 revives needed).