Breath of Fire
Posture: Sit in easy pose with your hands resting on your knees
Eyes: Keep eyes closed, gently focusing up and in at the brow point
Breath: Begin an even inhale and exhale through the nose. The breath should be strong and rapid, but even. Do not overemphasize the exhale or put too much emphasis on the navel.
Time: 3 - 11 min.
Here is a 30 Min Sadhana Set with warm up to breath of fire - you are welcome to use this on a daily basis to help you build up your endurance.