Slow Respiration

A character with this proficiency has the ability to enter a deep trance and reduce the amount of air he needs to stay alive. To induce the trance, he must be in a restful position, either sitting or lying down. After concentrating for one turn, pulse and breathing drop well below normal, so that breathing requires only 10% of the rate when resting. The character emerges from his trance at will, fully aware of anything that has occurred nearby.

[Complete Book of Dwarves]