Pranayama: Controlling the Mind Through The Breath
Pranayama is derived from two Sanskrit words – prana (life) and ayama (control). Pranayama is therefore life control and not “breath control.” The broadest meaning of the word prana is force of energy. In this sense, the universe is filled with prana; all creation is a manifestation of force, a play of force. Everything that was, is, or shall be, is nothing but the different modes of expression of the universal force. The universal prana is thus the Para-Prakiti (pure Nature), immanent energy or force which is derived from the infinite Spirit, and which permeates and sustains the universe.
~Paramahansa Yogananda, God Talks with Arjuna: The Bhagavad Gita, Page: Volume 1, 497

Pranayama Yoga chart Photographic reproduction of an illustration from Yogini Sunita (b. 1941), Pranayama Yoga: The Lotus and the Rose: The Art of Relaxation, Walsall, England, 1965
Prana
Prana is the vital energy that sustains life and is transmitted through the breath; ayama refers to the control, lengthening, or extension of that energy. Also referred to as Chi, Qi, or Ki, this life-sustaining force may be harnessed and directed through breathing techniques used to bridge the connection between the body and mind. Pranayama was developed through ancient yogic practices to create the requisite inner stillness necessary for the meditational practices of the latter three limbs: dharana, dhyana, and samadhi. The breath is manipulated through specific combinations of inhalation, exhalation, and suspension, also known as puraka, rechaka, and kumbhaka. Pranayama aims to control the breath, so we may learn to control the mind.
Prana is said to be distributed through 72,000 tube-like energy circuits called nadis, linking our astral body to the physical body. The three main nadis are located to the left and the right of the spinal column, and within the, shushumna, the spinal fluid of the column itself. The left nadi, Ida, has a cooling effect; the right, Pingala, has a heating effect. The breath is alternatively carried through the right and left nostrils, switching about each hour of the day. Prana is directed through the sushumna when the Kundalini Shakti–the dormant force that is coiled at the base of the spine–has been awakened. When this awakening has occurred, the prana is no longer carried with the breath; our breathing is said to cease at this point, which automatically results in kumbhaka. We must remember that the breath is not prana itself, it is the carrier. Prana is said to sustain life without the breath.
The Five Pranas
Prana moves within and without the body by five directional forces:
- Prana: Enters through inhalation
- Samana: Retains air in the lungs to absorb oxygen
- Vyana: Retains oxygen within the bloodstream and distributes it within the body
- Udana: Exhalation of breath and positive speech
- Apana: Releases carbon dioxide and stale air from the lungs through exhalation
The Five Pranic Breaths
The goal is first to merge the ascending prana, representative of air, with the gravitational pull of descending apana, which causes aging, death and disease (if we allow it to drag us down). If both prana and apana unite at the navel, then the body will be rejuvenated and revitalized. According to Fawley’s Yoga & Ayurveda, optimal health, energy, and awareness it is best brought on by the practice the “Five Pranic Breaths,” which can be found here.