Prana is not merely a philosophical concept; it is in every sense a physical substance. Just as radioactive or electromagnetic waves exist even though we can’t see them, in the same way, in this physical body, there are pranic waves and a pranic field. Now, each of us has a certain quantity of Prana in our physical body and we utilize this in the course of our day to day activities throughout life. When our Prana diminishes, sickness sets in, and when we have plenty of Prana, every part of the body is in perfect health. If we have an excess of Prana, it can be transmitted to others for healing or magnetism. The inner Prana can be stimulated by the practice of Pranayama and thereby increased to a greater quantum

One should not think that just by practicing a little Pranayama one can send a lot of Prana to the brain. The process of supply and assimilation of Prana into the brain is very complicated. The brain is a subtle instrument and it can only be enriched by the subtle form of Prana and not the gross form. Therefore, while practicing Pranayama, one has to convert the Prana into a subtle force. Deep breathing alone is not enough to stimulate Prana. By breathing deeply, respiratory system and the blood circulation are stimulated but if the brain is examined at that time, it would be seen that it is least affected. However, practicing Pranayama with concentration, as shown by scientific studies, the brainwaves undergo a significant change and the limbic system is also positively influenced.

The brain can be split into two parts- the frontal brain and the posterior brain. The posterior brain is the instinctive brain which we have inherited. The frontal brain is the seat of total consciousness. When you breathe without awareness, the breath is registered in the posterior brain, but when you are aware that you are breathing and you are consciously witnessing the whole process, then it is registered by the conscious brain, the frontal brain. This difference seems to be very simple, but its effect is very great. Throughout life, you breathe unconsciously, just like animals, children and most other people do, excepting for the few who have started practicing yoga. Now, in every case, the pranic flow is being registered in the posterior brain as if in a computer. The moment you become aware of your breathing and you begin to conduct and control the breath in a particular fashion, immediately the frontal brain registers the influence.