Holding your breath

You may declare you are holding your breath at the start your turn, or as an immediate action, in order to avoid the effects of an environmental hazard or creature ability which is triggered by being inhaled. Holding your breath costs a standard action each round you wish to maintain it. (This is not because the act of holding your breath is time-consuming, but because you are avoiding vigorous activity. You are forgoing your standard action in order to move around less and thereby reduce your need to breathe.) At any time, as a free action (even outside of your turn), you may stop holding your breath, but you do not recover any standard actions you have already sacrificed.