Kriya Yoga procedure cannot be fully explained theoretically but the science beyond Kriya yoga can be explained. Kriya yoga is a simple, psychophysical method by which the human blood is decarbonized and recharged with oxygen. The atoms of this extra oxygen are transmuted into life current to rejuvenate the brain and the spinal centers. The Yogi is able to lessen or prevent the decay of the tissues by stopping the accumulation of the venous blood. The advanced Yogis have the ability to transmute their cells into pure energy.
Kriya Yoga is an ancient science. Lahiri Mahasaya received the technique from his guru, Babaji, who rediscovered and clarified the techniques of Kriya Yoga. In this technique Yogi is able to neutralize both inhaling breath and outgoing breath. He thus releases the life force from his heart and brings it under his control. The yogi arrests the decay of body by addition of this life force and arrests the mutations or changes of body by 'Apan' or eliminating current. Thus by neutralizing decay and growth and by tranquilizing the heart, the Yogi learns the way of controlling the life.
Patanjali refers a second time to the life-control or Kriya technique thus: "Liberation can be accomplished by that pranayama which is attained by disjoining the course of inspiration and expiration."
In the initial state of God- contact or the Saibakalpa Samadhi, the devotee's consciousness merges with the cosmic spirit, his life force is withdrawn from the body and thus the body appears dead or motionless and rigid. The Yogi is full aware of his bodily condition and suspended movement. Then he progresses to the higher spiritual state or the Nirbikalpa Samadhi. However he communes with God without material body and in his ordinary awakening consciousness. The Yogi can achieve this state even in the midst of worldly duties.
Kriya Yoga is an instrument through which human evolution can be quickened. "The ancient yogis discovered that the secret of cosmic consciousness is intimately linked with breath mastery. This is India's unique and deathless contribution to the world's treasury of knowledge. The life force, which is ordinarily absorbed in maintaining the heart-pump, must be freed for higher activities by a method of calming and stilling the ceaseless demands of the breath."
Kriya Yoga is an instrument to quicken human evolution. The ancient Yogis discovered that the secrecy of cosmic consciousness lies within breath mastery. This is India's unique contribution to the knowledge of being immortal. The life force, which is ordinarily absorbed in maintaining heart pump, must be freed from higher activities by calming the breath rate.
The Kriya Yogi directs his mental life energy to revolve in upward and downward motions around the six spinal centers viz. medullary, cervical and coccygeal plexuses or Chakras. This corresponds to the twelve astral signs of the zodiac. There is an astral system within the human body; with six inner constellations revolving around the sun of the omniscient spiritual eye and the whole system is interconnected with twelve zodiac signs and the physical sun. All the mankind is affected by inner and outer universe in this way. The ancient sages discovered man's earthly and heavenly environment in twelve years cycles. One thousand Kriya practiced in eight hours is equivalent to one thousand years of natural evolution thus three hundred and sixty five thousand years of evolution is achieved within one year. Thus in three years a Kriya Yogi can accomplish the same result which nature brings in a million of years by the self-effort. With the guidance of the Guru, the Yogis have carefully prepared their bodies and brains to receive the power generated by the intensive practice of Kriya Yoga.
The beginner of Kriya Yoga practice employs his yogic exercise only fourteen to twenty eight times, twice daily. Thus they achieve liberations in six, twelve, twenty-four or forty-eight years. A yogi who dies before achieving full realization carries with him the good Karma of his past Kriya Yoga and the new life he attains harmoniously propelled toward the Infinite Goal. Through gradual and regular practice of the simple and foolproof methods man's body becomes astrally transformed day by day, which is finally fitted to express the infinite potential of cosmic energy, which will in turn express the materially active spirit.
Kriya Yoga is not forceful control of breath. It is the accession of peace and soothing sensations of regenerative effect in the spine. The ancient Yogic techniques are able to convert the breath into mind.
Mathematical relationship could be drawn between man's respiratory rate and the variations in the state of consciousness. A person whose attention is fully engrossed, his/ her breath becomes automatically slow. Sureness of attention depends on slow breathing while quick or uneven breaths are an inevitable indication of harmful emotional states like fear lust and anger. There is also evident in animal world. The animals whose longevity is higher than Man, like elephants, tortoises etc have much slower breathing rate.
The sleep has a rejuvenating effect on human being as the temporary unawareness of body and breathing is very important. The sleeping man becomes yogi as the sleeper is dipped unconsciously in the vast ocean of cosmic energy, which sustains all life. The voluntary Yogi performs a Yogic rite in a simple natural process consciously, not unconsciously like the slow-paced sleeper. The Kriya Yogi uses his technique to saturate and feed all his physical cells with a light and keep them in magnetized state. He makes the breath scientifically unnecessary, without producing the states of subconscious sleep or unconsciousness.
During Kriya Yoga the Yogi's body and brain cells are electrified with a spiritual current. It needs twelve years of normal healthful living to effect the slight perceptible change in brain structure. Kriya unties the cord of breath which binds the soul to the body, Kriya serves a prolong life and enlarges the consciousness to the infinity. This yogic method frees the devotee to reinherit the eternal kingdom. Introspection or 'sitting in the silence' is an unscientific way to force apart the mind and the senses, tied together by life force. The contemplative mind, attempting in return to divinity constantly dragged back towards the senses of life currents. Kriya is the easiest method, which controls the mind directly through the life force. It is also the most effective and most scientific avenue of approaching the Infinite.
The Science of Kriya Yoga is based on an empirical consideration of all forms of concentration and meditation exercises. Yogi is able to switch off or on the life current at his own will to the five senses of sight, sound, smell, taste and touch. The Yogi can unite the mind with the divine realms or with the world of matter. Even the Kriya Yogi is able to win over his last enemy, the death.
The Kriya Yoga practitioner always avoids the path of good and bad, the egoistic work of a common life. The superior method of soul living frees the Yogi, who is no more bound in the ego prison and tastes the deep air of the omnipresent. In an ordinary life the man is a puppet of his past actions (karma) and of nature and his surroundings. The Kriya yogi passes beyond all the illusions into his unfettered being. All ancient scriptures describe man not as the corruptible body but a living soul. The Bhagavat Gita describes Kriya Yoga as the real 'fire rite'. The purifying fires of Yoga bring eternal illumination, and thus differ much from the outward and little-effective religious fire ceremonies.
The advanced Yogi withholds his entire mind, will and feeling from the false identification with bodily desires, uniting his mind with super conscious forces in the spinal area, not impelled by the impulses from the past. Such a Yogi receives fulfillment of his supreme desires, which is the final harbor of the blissful spirit.
The advanced Yogi withholds his entire mind, will and feeling and offers his labyrinthine human longings to the unparallel god. This is indeed the true Yogic fire ceremony, in which all past and present desires are burnt for Divine Lord. The ultimate flame is the symbol of sacrifice of human insanity and man is free from the longings. Lord Krishna praises the technological yogi in the following words: "The yogi is greater than body-disciplining ascetics, greater even than the followers of the path of wisdom (Jnana Yoga), or of the path of action (Karma Yoga)"