Prana is the universal principle of energy or force. It is the sum total of all energy that is manifest in the universe, all the forces in nature and powers which are hidden in men and which lie everywhere around us. This prana remains in a subtle, motionless, unmanifested, undifferentiated state during the cosmic pralaya, dissolution. When the vibration is set up, prana moves and acts upon akasha, space, and brings forth the various forms. The macrocosm, brahmanda, and microcosm, pindanda, are combinations of prana and akasha.
All forces, all powers and prana spring from the fountain or common source, known as atman. Heat, light, electricity, magnetism are manifestations of prana. It may be in either a static or a dynamic state. It is found in all forms from the highest to the lowest, from the ant to the elephant, the unicellular amoebae to man, from the elementary forms of plant life to the developed forms of animal life.
Whatever moves or has life is but an expression or manifestation of prana. It is prana that shines in your eyes. It is through the power of prana that the ear hears, the eye sees, the skin feels, the tongue tastes, the nose smells and the brain and the intellect perform their functions. The smile of a young lady, the melody in music, the power in the emphatic words of an orator, the charm in the speech of ones beloved are all due to prana. Whatever you behold in this sense-world, whatever moves or works or has life, is but an expression or manifestation of prana.
Prana is force, magnetism and electricity. Radio waves travel through prana. That which moves the steam engine of a train and a steamer, which causes the motion of breath in lungs, that which is the very life of this breath itself, is prana. It is prana that pumps the blood from the heart into the arteries or blood vessels. Through prana digestion, excretion and secretion take place. Prana digests the food, turns it into chyle and blood, and sends it into the brain and mind. The mind is then able to think and enquire into the nature of Brahman.
Prana is the link between the astral and physical body. When the slender thread-link of prana is cut, the astral body separates from the physical body. Death takes place. The prana that was working in the physical body is withdrawn into the astral body.
Hatha yogins consider that the prana tattwa, the energy-principle is superior to manas tattwa, the mind-principle. Prana is present even when the mind is absent during sleep and therefore, prana plays a more vital part than the mind. If you go through the parables in Kaushitaki and Chhandogya Upanishads, when all the indriyas, senses, mind and prana fight amongst themselves as to their superiority, you will find that prana is regarded as the highest tattwa of all. Prana is the oldest, for it starts its functioning from the very moment a child is conceived, whereas the organs of hearing, etc. begin to function only when their special abodes, viz. the ears, etc. are formed.
Prana is called jyeshtha, oldest, and sreshtha, best, in the Upanishads. Through the vibrations of psychic prana, the mind, and sankalpa or thinking, is maintained and thought is produced. You see, hear, talk, sense, think, feel, will, know, etc. through the help of prana and therefore shrutis declare, Prana is Brahman.
Though the antahkarana, the inner instrument, is one, yet it assumes four forms: i) manas, the thinking mind, ii) buddhi, intellect, iii) chitta, memory or consciousness and iv) ahamkara, ego, according to the different functions it performs. Likewise, though prana is one, it assumes five forms: i) prana, ii) apana, iii) samana, iv) udana and v) vyana according to the different functions it performs this division is termed as vritti bheda.
Of these five, prana and apana are the chief agents. The seat of prana is the heart, its function is respiration; of apana, the lower abdomen to the anus, its function is excretion; samana, in the region of the navel, performs digestion; udana, in the throat, is responsible for swallowing and takes the jiva, the living being, to sleep, and separates the astral body from the physical body at the time of death; while vyana is all-pervading, it moves all over the body and is responsible for the circulation of blood.
Naga, koorma, krikara, devadatta and dhananjaya are the five sub-pranas. Naga is responsible for the functions of eructation and hiccup. Koorma performs the functions of blinking and opening the eyes. Krikara induces hunger and thirst. Devadatta is the prana which causes the action of yawning. Dhananjaya causes decomposition of the body after death.
Prana is said to be of the colour of blood, red gem or coral. Apana is of the colour indragopa (an insect of white or red colour). Samana is of the colour between that of pure milk or crystal and an oily shining colour, that is, something between both prana and apana. Udana is of an apandara, pale white, colour and vyana resembles the colour of archis, a ray of light.
Prana is expended by thinking, willing, acting, moving, talking and writing. A healthy strong person has an abundance of prana (or nerve-force or vitality). It is supplied by food, water, air, solar energy, etc. The supply of prana is taken up by the nervous system. The prana in the air is absorbed by breathing. The excess is stored in the brain and nerve centres. When the seminal energy is sublimated or transformed it supplies an abundance of prana to the system. It is stored in the brain in the form of spiritual energy.
The yogi stores a great deal of prana through the regular practice of pranayama, just as the storage battery stores electricity. That yogi who has stored a large supply radiates strength and vitality all around. He is a big power house and those who come in close contact with him imbibe prana from him and receive strength, vigour, vitality and exhilaration of spirits. Just as water flows from one vessel to another, prana actually flows like a steady current from a developed yogi towards weak persons. This can actually be seen by the yogi who has developed his inner yogic vision.
The yogi who becomes an expert in the knowledge of prana, will have no fear of any power, because he has mastery over all the manifestations of powers in the universe. What is commonly known as the power of personality is nothing more than the natural capacity of a person to wield his prana. Some persons are more successful in life, more influential and fascinating than others. It is all due to the power of this prana. Such people manipulate every day, unconsciously of course, the same influence which the yogi uses consciously by the command of his will.
A yogi can withdraw prana from any area of the body. That area gets benumbed, becomes impervious to heat and cold and has no sensation. A yogi can also send prana to any area and make it oversensitive; he can send it to the eyes and see distant objects; he can send it to the nose and experience divine aromas; he can send it to the tongue and experience super-sensuous taste.
By control of prana the yogi can also control the omnipresent manifesting power out of which all energies take their origin, whether concerning magnetism, electricity, gravitation, cohesion, nerve currents, vital forces or thought vibrations; in fact, the total forces of the universe, physical and mental. A comprehensive knowledge of prana and its function is absolutely necessary for pranayama.