Lasting Breath

This spell increases the amount of time a character can hold his breath. As described in the Player's Handbook, a character can hold his breath for a number of rounds equal to one-third his Constitution score. The effect of this spell is added to that figure.

The duration of the spell is always unknown to the recipient; the DM secretly rolls 1d4 to determine the exact duration. At the end of this time, the character must succeed a Constitution check or be forced to take a breath as per the rules.