Practicing the Breathing Technique
The Hatha Yoga Pradipika uses the name Nadi Shodhana for Anulom Vilom Pranayama and describes it in the following way:
The Yogi seated in Padmasana should draw in the Prana through the moon Nadi (left nostril) and having retained it according to his capacity, should release it through the sun Nadi (right nostril).
The above verse tells us to inhale through the left nostril, hold to our capacity, then exhale through the right nostril.
Again, drawing in the Prana through the sun Nadi, he should inhale to his capacity and hold the Prana in the abdomen. Having systematically and correctly performed Kumbhaka (breath retention), he should release it through the moon Nadi.
Here we are told to repeat the Anulom Vilom sequence going the other way, and we learn more about the inhalation and holding. The text says to inhale to our capacity, which means inhale fully enough to feel a stretch in the belly. Our holding must be systematic, which means we must be able to repeat it again and again. If you hold your breath too long on one side, your retention will be shorter on the other side. Holding to capacity, then, is the longest you can hold without compromising the sequence on the other side.
Through that particular Nadi which Prana is released, draw in the Prana again. Retaining it with much effort, he should slowly release the Prana using the other nadi. He should not release forcefully or quickly.
Here the Anulom Vilom Pranayama technique is summarized, and we learn that we are to hold with “much effort.” The effort comes from finding the fine line between holding as long as we can and maintaining the length of the holding on the other side. This requires incredible discernment. This verse also tells us we must be able to exhale slowly and with control. This helps ensure that we don’t hold too long, in which case we’d need to exhale sharply. Through the alternate nostril breath, we are building strong energy and challenging the mind to stay present so that releasing the breath is a conscious choice, not a reaction.
If one draws in the Prana through the moon Nadi, one should release the restrained Prana through the sun Nadi. If the Prana was drawn in by means of the sun Nadi, after the holding, the Prana should be released by means of the moon Nadi. As a result of the regular practice of this process, the mass of many Nadis becomes unified within three months.