Editing Open4E:Hit Points (section)

=Hit Points=

Hit points represent a character’s ability to withstand damage and keep fighting. A character’s base hit points are equal to twice their Constitution score, plus any points gained from their character class. A character gains a certain number of hit points per level (including first level); these are added to their base hit points to determine their total hit points. 

Attacks which would harm your character are normally subtracted from your hit points. A character who has lost half their total hit points is bloodied; certain actions and effects only affect a bloodied character. Once your hit points are depleted, you are dying - a dying character must make an Endurance save each turn to stabilize, with a DC equal to the amount of damage they have taken in excess of their hit points.