The extended exhalation in this breathing exercise is very good for pregnant women in preparation for labor. This exercise produces a sweet clear voice and is highly recommended for singers. This is also excellent for reducing tension. Instructions for Brahmari Breathing
In this breathing exercise you inhale through both nostrils but you must close your glottis as you do so. The glottis is the part of the larynx made up of the vocal cords and the slit like opening between them. This has the effect of making a snoring sound as you inhale. Then you exhale through both nostrils very slowly humming like a bee. Humming while you exhale allows you to prolong the breath and spin it out. Practice making these sounds then apply them to the breathing exercise.
Should repeat five to ten times.