Dirgha Pranayama or the Complete Breath 

Dirgha breath is also known as the "three part breath." This pranayama focuses on the three chambers of the lungs. The first is the lower level of the abdominal area just under the floating ribs . This is the area that allows you to inflate like a balloon. The second area is the middle chest, or thoracic region just under the sternum. Breathing into this area lifts your rib cage and expands and contracts the intercostal muscles. The third section, or upper chamber, is in the clavicle region, located in the area of the upper chest and shoulders, up to the collar bone.

Technique:

Begin sitting in a comfortable cross legged position. Or, lying on your back in Savasana, corpse pose. Relax the body, yet keep it active and alive. If sitting keep the spine straight. Close the eyes and begin to focus on the breath. With each inhalation lift the torso. Expand the rib cage. If you like, you can begin with Ujjayi Pranayama. Place the hands on your abdomen. With each inhalation, notice how much you expand. With each exhalation, become aware of the rib cage contracting. Release tension with each exhalation, allowing the belly to drop further into your hands.
Once you feel comfortable, move your hands to the middle abdomen. On your next inhale, fill the first chamber. Then the middle chamber. Again notice your middle area expanding and contracting. And notice any restrictions in the muscles or breath. Now incorporate the last step which is to breath into the final chamber of the lungs. To see if you are fully breathing into the third chamber, place your fingers on one side of your clavicle bone, your thumb on the other side, cupping around your neck.

Begin to breath into the lower chamber, then the middle chamber then the third chamber. Feel your fingers rise up. Keep the breath smooth by synchronizing the inhalation and exhalation. On the exhales, let the breath spill out from the top to the bottom like a pitcher of water pouring out. On the inhalation fill the pitcher up. At all times keep the breath smooth, effortless, and rhytmic. Be aware of any tension in the body and release it through the exhalation.

Like Ujjayi Pranayama, Dirgha pranayama is a wonderful tool for stimulating more internal awareness, calming the mind through the breath, and preparing you for deeper meditation.

Some of the effects:

Dirgha pranayama calms the mind and relaxes the body, revitalizes the entire nervous system, delivers oxygen rich blood to the furthest area of the lungs, breaks irregular breathing patterns, and habitual shallow breathing, improves digestion and elimination, helps relieve constipation, strengthens the abdominal muscles, diaphragm, heart and lungs, and soothes discomfort during menstruation.

Precautions:

If you feel dizzy or light-headed stop for a few minutes then resume. Perhaps spend shorter amounts of time practicing this breath.