Now let us come down from the philosophical to the practical. Yoga, as popularly understood, is of the physical body and is very much a technical subject. We have to study the anatomy of the body in relation to the mind in its psychological terms.
The three states of mind, as described in the last paragraph, are the qualities of the mind that influence it. Here, in HATHA YOGA, or yoga in practice, we deal with the three elements of the body, its three main channels, the NADIS, or the nerves, known as the IDA, the PINGALA and the SUSHUMNA.
The ‘ida naadi’, is the carrier of mental energy, the ‘pingala’, the ‘pranic’ or life’s energy, while the ‘sushumna’ is the channel of spiritual consciousness of the self, that is the ATMAN. Our spinal column (or the spine) is the frame-work for the flow of energy through these three channels, the nadis, or nerves.
In this indoctrinal system, the Ida’ flows through the left nostril, and the ‘pingala’ through the right. ‘Ida’ is temperate and cooler than ‘pingala’.
When ‘ida’ is functioning, the right side of our brain is operating and when ‘pingala’ functions, the left side of the brain operates and when the ‘sushumna’ awakens, the whole brain goes into operation.
The flow of ‘ida’ and ‘pingala’ goes through the spinal column to the entire body, controlling the different organs, such as the kidneys, the bladder, the stomach, the lungs, the heart, etc. Some organs are fed by ‘ida’, the others by ‘pingala, and some by the both.
Through the frame-work of these nadis, or nerves, the body receives both the ‘prank’ (life’s) and also the mental energies. Hatha Yoga aims at creating a balance between ‘ida’ and ‘pingala’ that is, between the ‘pranas’ (life’s) and the ‘chitta’ (mental) energies.
When that state of balance happens, the ‘sushumna nadi’ wakes up and then is revealed or released the hidden potential of the mind.
The ‘prana’, that is, the life force and the ‘chitta’, that is, the thought force are the two responsible factors of our existence. The ‘pranas’ feed the ‘karmendriyas’ (action nerves) and the ‘chitta’ feeds the ‘gyanendriyas’ (sensory nerves).
In the system of our body, it is the ‘chitta’ that makes us see, smell, hear, taste, or feel through the ‘pranas’.
When the ‘prana’ energy, or the flow in the ‘pingala’ is predominant, the consciousness of the external is more than normal and when ‘chitta’ or the flow of ‘ida’ predominates, the person thinks, deals in fantasies and plans.
It is only a balanced working of both, that is considered healthy and for this is advised the practice of Hatha Yoga—the practice of asanas, etc.—supported by PRANAYAMA and DHYANA YOGA.