Holding Your Breath Under normal circumstances (with a good gulp of air and not performing strenuous feats), a character can hold his breath up to '/3 his Constitution score in rounds (rounded up). If the character is exerting himself, this time is halved (again rounded up). Characters reduced to Ys or less of their normal movement because of encumbrance are always considered to be exerting themselves. If unable to get a good gulp of air, these times are reduced by 1/2. All characters are able to hold their breath for one round, regardless of circumstances. While attempting to hold his breath beyond this time, the character must roll a Constitution check each round. The first check has no modifiers, but each subsequent check suffers a —2 cumulative penalty. Once a check is failed, the character must breathe (if he cannot reach the surface, he drowns).