In this post I want to propose a preparatory exercise to Pranayama: Utthita LOLASANA ( standing position swing ). The position is upright and your feet are separated by about a meter. Before you begin you must search for the roots to the ground.
Lift arms up while keeping your elbows straight, bend your wrist forward so your hands hang freely.
bends forward swing, leaving the trunk from the hips, letting his arms and his head between his legs wobble. 
Trying to be free of tension, like a rag doll.
oscillation upwards, lifting the torso parallel to the floor; oscillation down as much as possible bring your hands back over your feet.
After 5 complete oscillations return to an upright position with arms raised, then lower your arms sideways.
Repeat 5 times.
breathing: inspiration through the nose as you raise your arms and when you return to standing position. Exhale forcefully through your mouth with every swing downwards making sure that all the stale air is expelled from the lower lobes of the lungs.
While you swing upward slightly inspiration is only a slight reflex action, but the main objective is to completely empty the lungs downward oscillation.
asana practice is an excellent pre-pranayama as it opens all the alveoli and rebalances the exchange ventilation-perfusion in the lungs.
But here's the video ...
