From pranayama (q.v.) arises laghava (lightness).

All beings say the ajapa Gayatri, which is the expulsion of the breath by Hangkara, and its inspiration by Sahkara, 21,600 times a day. Ordinarily, the breath goes forth a distance of 12 finger's breadth, but in singing, eating, walking, sleeping, coition, the distances are 16, 20, 24, 30, and 36 breadths respectively. In violent exercise these distances are exceeded, the greatest distance being 96 breadths. Where the breathing is under the normal distance, life is prolonged. Where it is above that, it is shortened. Puraka is inspiration, and rechaka expira-tion. Kumbhaka is the retention of breath between these two movements. Kumbhaka is, according to the Gheranda Sanghita of eight kinds: sahita, suryyabheda, ujjayi, shitali, bhastrika, bhramari, murchchha, and kevali. Pranayama similarly varies. Pranayama is the control of the breath and other vital airs. It awakens shakti, frees from disease, produces detachment from the world, and bliss. It is of varying values, being the best (uttama) where the measure is 20; middling (madhyama) when at 16 it produces spinal tremor; and inferior (adhama) when at 12 it induces perspiration. It is necessary that the nadi should be cleansed, for air does not enter those which are impure. The cleansing of the nadi (nadi-shuddhi) is either samau« or nirmanu, that is, with or without, the use of vija. According to the first form, the yogi in padmasana does gurunyasa according to the directions of the guru. Meditating on "yang," he does japa through Ida of the vija 16 times, kumbhaka with japa of vija 64 times, and then exhalation through the solar nadi and japa of vija 32 times. Fire is raised from manipura and united with prithivi. Then follows inhalation by the solar nadu with the vahni vija 16 times, kumbhaka with 64 japa of the vija, followed by exhalation through the lunar nadi and japa of the vija 32 times. He then meditates on the lunar brilliance, gazing at the tip of the nose. and inhales by Ida with japa of the vija "thang" 16 times. Kumbhaka is done with the vija vang 64 times. He then thinks of himself as flooded by nectar, and considers that the nadi have been washed. He exhales by Pingala with 32 japa of the vija lang, and considers himself thereby as strengthened. He then takes his seat on a mat of kusha grass, a deerskin, etc., and, facing east or north, does pranayama. For its exercise there must be, in addition to nadi shuddhi, consideration of proper place, time, and food. Thus, the place should not be so distant as to induce anxiety, nor in an unprotected place, such as a forest, nor in a city or crowded locality, which induces distraction. The food should be pure, and of a vegetarian character. It should not be too hot or too cold, pungent, sour, salt, or bitter. Fasting, the taking of one meal a day, and the like, are prohibited. On the contrary, the Yogi should not remain without food for more than one yama (three hours). The food taken should be light and strengthening. Long walks and other violent exercise should be avoided, as also, cer-tainly in the case of beginners, sexual intercourse. The stomach should only be half filled. Yoga should be commenced, it is said, in spring or autumn. As stated, the forms of pranayama vary. Thus, sahita, which is either with (sagarbha) or without (nirgarbha) vija, is, according to the former form, as follows: The sadhaka meditates on Vidhi (Brahma), who is full of rajoguna, red in colour, and the image of akara. He inhales by Ida in six measures (matra). Before kumbhaka he does the uddiyanabandha mudra. Meditating on Hari (Vishnu) as sattvamaya and the black vija ukara, he does kumbhaka with 64 japa of the vija; then, meditating on Shiva as tamomaya and his white vija makara, he exhales through Pingala with 32 japa of the vija; then, inhaling by Pingala, he does kumbhaka, and exhales by Ida with the same vija. The process is repeated in the normal and reversed order.