|Ida, Pingla and Sushumna|
Swar Yog is knowledge of cerebral respiration.Air is useful outwardly as well as inwardly in a subtle way. By its inward use one is spiritually uplifted, enjoy worldly pleasure and good health. The science of Swar is like Pranayama in which subtle use of air element is made.
The science of Swar or control of Swar is a branch of Yoga. The science of Swar is based upon the passage of air through our nostrils. We breathe day and night, but air does not pass equally through both our nostrils. It is seen that we breathe through one nostril for a certain period and then through the other nostril. When breathing or swar stops through one nostril and starts through the other, it is called Swarodaya.
When we breathe through the left nostril it is known as Ida or Chandra Swar or Moon Swar, and when we breathe through the right nostril it is known as Pingla or Surya Swar or Sun Swar. When we breathe equally through both nostrils it is known as Sushumna.
Left Swar (Ida)
When the left swar is running, it is time when any stable, peaceful and good work is undertaken, such as to make friends, to sing the praise of God, to beautify oneself, to start medical treatment, to give alms, to perform yagya, to start the construction of house, to start a journey, to buy or sell, to sow the fields or to start education etc.
Right Swar (Pingla)
When the right swar is running it is time to undertake hard and difficult tasks, such as horse riding, starting a journey, exercise, climbing a mountain, sexual enjoyment, taking bath or food.
When equal swar is running through both nostrils, it is time to do yoga, meditation or thinking. Things which are to be done when left or right swar are running should not be done during Sushumna, otherwise it will have bad effect.