A being has four divisions - material body, life-force (Prana), mind, and soul (Atman). In fact these four are one. The subtler part of body is Prana, subtler part of Prana is mind, and subtler part of mind is Atman. Only the body is visible and destructible; Prana, mind and Atman are invisible, indestructible, eternal and divine.
The body with its cells and organs remains active and alive for the flow of fluids throughout the body. The flow of fluids goes on relentlessly because there is a life-force (Prana) that flows throughout the body. This flow of Prana is felt easily by the inhalation and exhalation of air across the nostrils. Flow of air is not Prana but flow of Prana moves the air across the nostrils as well as fluids throughout the body.
The subtler part of Prana is mind. So mind has control over Prana and so over the body. For example when mind thinks to do something, both body and Prana move faster to do so. When mind wants to take a rest, both body and Prana slow down and take a rest.
However we can notice that even if we are taking rest and sleeping, breath moves as usual. So Prana moves and supplies energy relentlessly round the clock. From birth till death this Prana is working. Not only in present birth but in countless previous births also this Prana was working relentlessly. So it needs some rest from time to time. As in sleep we give rest to the tired body and after we awake we get a refreshed and energetic body, so by giving rest to Prana, we shall feel refreshed and tremendously energetic. By this we control and conserve Prana.
- Choose posture. First choose either sitting posture (Padmasana) or sleeping posture (Sabasana). Sabasana is better. For this lie on a soft and flat surface by spreading a blanket on the floor. Hands and legs should be stretched with face upwards and eyes closed.
- Relax the body completely. From tip of fingers in hands and legs, move your mind upwards across Chakras or joints, thinking that you are completely relaxed. By this, the wandering mind also remains inside the body.
- Keep your mind on the movement of air across the nostrils. Since body is at rest, metabolism in the body slows down and so inhalation and exhalation goes on very slowly. Since mind is kept on Prana and since movement of Prana has slowed down due to resting of body, everything (i.e. body, Prana and mind) slows down and come to a point. This union of body, Prana and mind is Pranayama. Body, Prana and mind are one and same and so they must come for union.
- Achieve Dhyana. When a practitioner stays in this position for at least fifteen minutes, he proceeds to deep concentration of mind called meditation (Dhyana). However in Pranayama, one gets refreshed and charged with energy. So you can rule over the body and thereby over the material world.
This method by which Prana is given rest is called Pranayama. It is a part of Yoga. Already there are various methods of Pranayama practiced throughout the world. But you should not do that Pranayama by which breath is held forcibly. Inhalation and exhalation should go on without a break. In the body metabolism in cells goes on continuously and so the carbon dioxide generated in cells should leave the body immediately through exhalation. In order to do true and correct Pranayama, you should remember and follow the steps described above.