In contemporary life, when most people hear the word "yoga" they think only of the physical poses and exercises of Vinyasa, the physical practice of Yoga. The physical poses and movements of Yoga are, however, only one small part of Yoga, the total mind-body system first delineated by Maharishi Patanjali over a thousand years ago.
Yoga, as a total system, has many components, many practices. There are practices that work with the conscious mind (inquiry, discrimination, study), practices that work with the emotions (pranayama and bhakti or devotion), practices that work with the awareness, that train the attention (mantra meditation) ethical practices (yama), behavioral practices (seva) and so on. All these practices are designed to work together to bring all parts of the person into alignment, into harmony, into well-being.
Pranayama, the fourth limb of Yoga, is a series of practices designed to support emotional equanimity and well-being, beginning with breathing exercises that soothe restlessness and anxiety.
The next set of practices take Pranayama to a deeper level, working directly with the emotions to harmonize them, resolving the habitual negative emotions (fear, anger, sadness) that block the full expression of life and spirit. This is what Patanjali called "the harmonizing of polarities."
On a more advanced level, Pranayama is a way of working directly and intentionally with the energy systems of the body (shaktipat), systematically releasing (nirodhah) interference patterns (vritti) that inhibit and limit the flow of life energies (chitta, prana) throughout the entire mind/body system.
We begin with the breathing. That's the first place to start. Soothe the breathing and the whole system comes more into alignment.
As a side-note, anti-anxiety breathing exercises, like deep belly breathing or the breathing exercises of the Lamaze Method of prepared childbirth are western practices that work in the same or similar way as ancient Yogic breathing techniques like ujjayi, nadi shuddhi and bastrika. The Chinese have Qigong breathing exercises as well. Every culture seems to have found it's own version of pranayama.
A couple of relevant quotes:
"The elegant shapes and impressive contortions of the asanas may be the most eye-catching element of hatha yoga, but yoga masters will tell you they're hardly the point of practice. According to yoga philosophy, the postures are merely preludes to deeper states of meditation that lead us toward enlightenment, where our minds grow perfectly still and our lives grow infinitely big. But just how do we make the leap from Downward Dog to samadhi? Ancient yoga texts give us a clear answer: Breathe like a yogi.
"Pranayama, the formal practice of controlling the breath, lies at the heart of yoga. It has a mysterious power to soothe and revitalize a tired body, a flagging spirit, or a wild mind. The ancient sages taught that prana, the vital force circulating through us, can be cultivated and channeled through a panoply of breathing exercises. In the process, the mind is calmed, rejuvenated, and uplifted. Pranayama serves as an important bridge between the outward, active practices of yoga--like asana--and the internal, surrendering practices that lead us into deeper states of meditation.
"My first American yoga teacher, a guy named Brad Ramsey, used to say that doing an asana practice without a pranayama practice developed what he called the Baby Huey syndrome," says Ashtanga teacher Tim Miller. "Baby Huey was this big cartoon duck who was very strong but kind of stupid. He wore a diaper. Basically what Brad was trying to say was that asana will develop your body but pranayama will develop your mind."
--Claudia Cummins, Prescriptions for Pranayama, Yoga Journal
"Pranayama is derived fron two Sanskrit words - prana (life-energy) 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-Prakriti (pure Nature), immanent energy or force which is derived from the infinite Spirit, and which permeates and sustains the universe."
"Yoga works primarily with this energy in the body, through the science of Pranayama, or energy control. Prana means also "breath." Yoga teaches how, through breath control, to still the mind and attain higher states of awareness. The higher teaching of yoga take one beyond techniques, and show the yogi, or yoga practitioner, how to direct his or her concentration in such a way as not only to harmonize human with divine consciousness, but to merge his or her consciousness into the infinite."
--Paramahansa Yogananda (1893 - 1952) Source: God Talks with Arjuna: The Bhagavad Gita
All of the “limbs” of Yoga — all of the precepts and practices of Yoga work together to bring all aspects of ourselves into harmony and alignment.
Yama and Niyama support right understanding, right lifestyle. Asana and Vinyasa focus on the physical practice of yoga, working with the body to produce a stable physical platform. Pranayama, the fourth limb of yoga, works with the breath, and also with the mind and emotions to produce a state of equanimity, serenity amid loss or gain (samapatti). Pratyahara clarifies the relationship of the mind to experience, and helps us learn to manage the undue influences of the world around us.
The practice of Yoga begins with an understanding which becomes a physical practice which becomes a mental and emotional practice which eventually becomes an energy practice, and all these levels of practice work toward reconciling the fundamental polarities of experience and existence.
Energy work is about balancing polarities -- yin/yang, positive/negative, here/there, sadness/joy, self/other, tension/flow, and this is the ultimate focus of yoga. As the sutra says, the yogi is unperturbed by the play of opposites. All duality is reconciled in yoga.
Pranayama, the fourth limb of Yoga, deals with energy beginning in the most obvious way: we work with the basic cycle of intake and outflow of breath -- and in harmonizing and balancing the breath, we "tune" the basic polarity of mind and body, inside and outside. Pratyahara, the next and fifth limb of yoga, has to do with removing the innappropriate influence of the outer world -- it lessens the intrusion of outer influences on us, and restores us to a balanced sense of subjectivity.
The term "pranayama" is used in the Sutras to describe both the practice of pranayama (the process: breathing exercises) and the state of pranayama (the goal: balanced energies).
The first three sutras, YS II:46, YS II:47, YS II:48 describe the prelimary conditions necessary for the successful practice of pranayama. The remaining four describe, in general terms, the practice of pranyama itself.
First, one's asana, or physical foundation, must be steady and comfortable. The body should be made to be as comfortable and as steady as possible. The mind should be, again, as much as possible, one-pointed -- free of distraction and conflict. The emotional state should be one of calmness and well-being. The practice of Yama, Niyama, and Asana, all work together to produce this stable platform, allowing the yogi to begin the practice of yogic breathing with a sense of stability and well-being.
Second, one needs to understand how to relax unceasingly -- physically, mentally and emotionally -- to continuously surrender all effort, all struggle, let go of and release all tension and strain. This is to be done until one is utterly relaxed and free from all sense of duality, all sense of struggle and effort. When we let go of all physical, then mental, then emotional tension and resistance, our sense of being expands. We "open up" and recover a profound sense of security and well being.
Ahimsa, non-aggression, the first precept of Yoga, becomes our way of being -- in fact all of the yamas and niyamas begin to arise in us spontaneously.
Then breathing becomes free and effortless, relaxed and comfortable. There is a sense of "breath taking place." The various types of pranayama, alternate nostril breathing for instance, allow us to focus on the breath in a gentle, natural ways, observing its movement in and out, becoming more aware of where the breathing takes place (abdomen or chest), the duration of the breath, and in the mind observing the breath in this way the breath naturally becomes more subtle, more peaceful, more extended.
This, in turn, gives rise to a deeper, broader perspective, a spaciousness of mind: thoughts become more soft, subtle, less conflicted, less compelling. We grow calmer, unperturbable. And our sense of conflict, struggle is reduced greatly. With the calming of the mind, the barriers to the shining of awareness diminish, and consciousness expands.
The mind grows steady, capable of focus and deliberate thought.
From the Yoga Sutras of Patanjali:
YS II.46 sthira-sukham-asanam
Asana is steady, comfortable.
YS II.47 prayatna-saithilya-ananta-samapattibhyam
And unceasing relaxing of effort renders the arising of non-dual, comprehensive awareness.
YS II.48 tato-dvandva-anabhighatah
As a result, one is unperturbed by the play of opposites.
YS II.49 tasmin-sati-svasa-prasvasayor-gati-vicchedah-pranayamah
(from this)(state)(breathing in and out)(flow)(cutting off)(energy-control)
To abide in this state of unceasing flow, throughout inhalation and exhalation, (is the state of) pranayama.
YS II.51 bahya-abhyantara-visaya-aksepi-caturthah
(The sense of) outer/inner, subject/object is transcended. This is the fourth limb of yoga.
YS II.52 tatah-ksiyate-prakasha-avanaram
Thus, that which obscured the shining of inner awareness diminishes.
YS II.53 dharanasu-ca-yogyata-manasah
And the mind gains the capability of steady focus.
And who wouldn't want that? A clear mind, a steady mind, a balanced mind that is able to focus. This is the gift, the benefit of the practice of pranayama.