(Lee Barklam)

A character can hold their breath for a number of combat rounds equal to twice their Strength score. Thereafter, they lose 1 Health Point per combat round until they draw breath. For each full minute of doing nothing but breathe heavily, they recover 1 of these Health Points (but no more than were lost through suffocation). Simply drawing a single breath will refresh the character enough to hold their breath again for a number of combat rounds equal to twice their Strength score, but will not replenish any lost Health Points.

If a character engages in strenuous activity while holding their breath (e.g., combat, running, swimming, etc.), the amount of time they can hold their breath before taking damage is halved to a number of combat rounds equal to their Strength score.