Kriya Yoga

Kriya Yoga is a discipline involving purification of the body-mind through breath control techniques to aid health and spiritual evolution. From the ancient master called Mahavatar babaji (a himalayan yogi , still believed to be living and more than 1,800 years old), Buddha, to current masters like Sri Sri ravi Shankar (Sudarshana Kriya) , Kriya Yoga and importance of breath techniques has always been given importance.

1. Lex Hixon in his book GreatSwan, Chapter :Advaita Vedanta also quotes Sri Ramakrishna teachings of chanting SoHAM (Iam that) accompanied with rhythymic inhalation/exhalation breathing techniques.

2. in Ananda Sutta or Anaspasati Sutta (Mindfullness of breathing) , Buddha sermons to Ananda on importance of having to focus on in and out breathing.

3. In the book "Strength of Stillness" by Aurobindo he mentions as follows "The greatest exertions are made with the breath held in; the faster the breathing, the more the dissipation of energy. He who in action can cease from breathing,--naturally, spontaneously,--is the master of Prana, the energy that acts and creates throughout the universe. It is a common experience of the Yogin that when thought ceases, breathing ceases,--the entire kumbhak effected by the Hathayogin with infinite trouble and gigantic effort, establishes itself easily and happily,--but when thought begins again, the breath resumes its activity. But when the thought flows without the resumption of the inbreathing and outbreathing, then the Prana is truly conquered. This is a law of Nature"
4. Svetashvatara Upanishad , Shankara quotes Yagnavalkya after explainign the postures and ambience of the meditation as "Then should be practiced Pranayama composed of Rechaka (exhalation), Kumbhaka (retention), and Puraka (inhalation). Joining the Prâna with the Apâna is Pranayama. In sixteen Matras filling the body from the head to the feet, in thirty-two Matras the Prana is to be thrown out, and with sixty-four the Kurnbhaka should be made...."