In the Chandogya, Katha, Prashna, Mundaka, and Aitareya Upanishads, life-force is called prāṇa; yet this term, used in the plural, refers to the five vital winds or breaths dwelling in the body—prāṇāpānādi. "As the life-force desires for the self, so too for all beings" (Hitopadesha: 1.11, 1.18); "The sheaths are sheaths for the sheaths; the life-breaths are the life-breaths of the life-breaths, not of the king" (2.91). Within the body, distinguished by location and function, there are five winds: (1) prāṇa—the wind seated in the heart, (2) apāna—in the lower orifice, (3) samāna—at the navel, (4) udāna—in the throat, (5) vyāna—pervading the entire body. Their respective functions are: food-ingestion, elimination of urine and excrement, digestion of food, speech and related acts, and blinking (sleep, inhalation, exhalation, discharge, intake, opening and closing of the eyes) (commentary on the Amarakosh). Some hold that the body contains five other winds: nāga, kūrma, kṛkara, devadatta, and dhanañjaya—responsible respectively for belching, closing the eyes, hunger, yawning, and nourishment. Yet in some schools of thought, these are subsumed within the prāṇādi group (Vedantasara). The word prāṇa, encompassing the collective aggregate of all vital winds, is always employed in the plural.
The five prāṇas indeed—five winds lodged within the body. The wind that resides in the body is called prāṇa. Prāṇa, apāna, samāna, udāna, and vyāna together form the pañcaprāṇa, the fivefold breath. The Amarakosh tells us: "Prāṇa, apāna, samāna, udāna, and vyāna are winds" (Amarakosh). These five prāṇas are stationed throughout the entire body; among them, in the region of the heart dwells the wind called prāṇa, in the lower region or at the anus dwells apāna, at the navel region samāna, in the throat region the wind called udāna, and vyāna pervades and inhabits the entire body.
"In the heart dwells prāṇa; apāna in the lower part;
Samāna dwells at the navel's seat;
Udāna in the throat region, vyāna through all the body spreads."
(Tarkamrta, Jagadish Tarkalankar)
According to Vedantic doctrine, among these five prāṇas, the upward-moving wind stationed at the tip of the nose is called prāṇa; the downward-moving wind dwelling at its source (the anus) is called apāna; the wind moving through all the channels, stationed throughout the entire body, is vyāna. The upward-moving wind of ascent situated in the throat is udāna; and the wind that equalizes ingested food and medicine (anupānādi)—bringing about the transformation of food into juice, blood, semen, excrement and the like—is called samāna. The Samkhya philosophers speak of five additional winds: nāga, kūrma, kṛkara, devadatta, and dhanañjaya. Among these, the wind that causes belching is nāga, the wind that opens the eyes is kūrma, the wind that produces hunger is kṛkara, the wind that causes yawning is devadatta, and the wind that nourishes the body is dhanañjaya. Yet the Vedantic teachers subsume these five subsidiary winds within the principal five—prāṇa and the rest—and speak only of these five prāṇas. This unified fivefold wind arises from the rajas or dynamic quality of the five great elements (earth, water, fire, air, and ether). Rajas is that quality inherent in any substance (nature) or person which activates and governs the functional activity of nature's other aspects—such as action, transformation, modification, emotion, excitement, birth, creation, and procreation. Thus, the prāṇa is divided into ten principal functions: namely, the five prāṇas (prāṇa, apāna, udāna, vyāna, and samāna) and the five subsidiary winds (nāga, kūrma, devadatta, kṛkara, and dhanañjaya).
When this five-fold life force unites with the five organs of action, it is called the vital sheath or the sheath of the living breath (Vedanta Sara). According to Vedantic philosophy, the life force possesses five distinct movements—prana, apana, samana, udana, and vyana. The forward-moving current is called prana; its function is the expression of vital impulses. The downward current is apana; its work is the expulsion of waste and excrement. That which functions at the meeting point of these two is called vyana; its task is to govern all the various functions driven by vital force itself. The upward current is udana; it is the cause of all utterance and actions emanating from the throat. That which functions equally throughout all parts of the body is samana. Through this samana wind, the essence of food, nutriment, blood, and other vital juices are carried and distributed evenly to all the organs of the body.
The nature of these five airs is nothing but the flow of conscious, transcendent power—in short, five distinct currents of the life force itself. The senses of knowledge and action establish connection with external objects. They are engaged in the formation, growth, and dissolution of our gross body; the life force serves as the seat and retention power for all sensations that flow from the outside world into our inner being.
In the region of the heart (the head, lungs, and heart) dwells prana—the internal, mobile power—whose movement is inward and upward. Prana is regarded as the primary air from which all other airs originate.
Vyana pervades the entire body (the distribution of vital energy)—it sustains and upholds life itself, "vyana moves throughout all the body" (Commentary on the Amara Kosha). "The airs are prana, apana, vyana, udana, and samana" (Vedanta Sara). Vyana is connected with the circulatory system, the nervous system, and the cardiac system. A balanced vyana maintains a healthy heart, proper circulation, and harmonious nerve function.
In the region of the throat dwells udana (the energy of the head and throat)—it is the source of capacity in speech and utterance, that by which the upper body is sustained (Commentary on the Amara Kosha); the upward-moving current of vital force centered in the throat region; "udana is that upward-moving air stationed in the throat, the cause of excretion and ascension" (Vedanta Sara). "The udana, that best of winds, rises upward" (Sushruta Samhita). When udana, samana, and vyana are in harmony, there comes restraint (Shyama Sangeet). The upward breath (A Sanskrit-English Dictionary by Monier-Williams). Its movement is upward; it relates to the function of the respiratory system, speech, and brain activity. A balanced udana ensures healthy respiration, clarity of speech, a composed mind, good memory, and creativity.
Below the navel and at the anal region dwells apana (the external, mobile force)—that which moves downward; the air stationed in the rectum; the wind of the lower orifices. "Apana is stationed [thus]" (Commentary on the Amara Kosha). "Apana is that downward-moving air dwelling in the anal and lower regions" (Vedanta Sara). "Making prana and apana equal in the passages of the nostrils"—that is, "the sage arrests the upward and downward motion of the prana and apana winds that move within the nostrils" (Bhagavad Gita, 5.27). That by which waste is made to descend; the path of excretion (Commentary on the Amara Kosha); the rectum, the anus, the path. Its movement is external and downward; it governs excretion, reproduction, and skeletal health through the absorption of nutrients. A balanced apana maintains healthy digestion and proper reproductive function.
In the region of the navel is perceived the dwelling of the air called samana (digestion and assimilation), located before the digestive fire in the stomach and small intestines. The work of samana wind is to digest food, activate the fire further, and separate the nutritious essence, waste, and urine. Its movement is spiral, centered around the navel, churning like the turning of milk into butter; it relates to digestion at all levels. A balanced samana ensures healthy metabolic function.
Let me speak briefly. The work of the vital force is to govern all from the seat of the heart. The function of directing energy-flow is performed by vyan; the separation of waste matter from the nutrient essence is called apan. The abode and sustaining power of bodily essences—the juices and blood and other humours—is named udan; the assimilation of food and drink, that is, the transformation of food and drink into juices, blood, and other essences, is called saman. In the ninth aphorism of the Nishvasatattva Samhita—composed in the sixth to tenth centuries—five subtle vital winds are described. Three of them are named nag, dhananjay, and kurm; the remaining two are mentioned in the Skanda Purana (181.46) and the Vayu Samhita of the Shiva Purana (37.36) as devadatt and krik. In the ninth aphorism of the Nishvasatattva Samhita, the origin and nature of the five vital winds are expounded.
True practitioners understand and know this vital force as the luminous power or as the Guru himself. These five streams of vital winds flowing from the luminous force sustain and preserve the gross body in perfect equilibrium through the power of consciousness itself.
When food is offered to the Guru, to the gods and goddesses, and the first oblation is made, the practitioner chants "To the vital force, hail!" With this utterance the vital force finds satisfaction; and through it, the eyes—the five sense organs contained within the vital force—also become satisfied. When the eyes are satisfied, the twelve Adityas (Aryama, Pusha, Tvashta, Savitri, Bhaga, Dhatri, Mitra, Vishnu, Varuna, Mitra, Ansha, Vivasvan or the Sun) are satisfied. Thus the gods dwelling in the celestial realm and those presiding over the sun are satisfied. As a result, the performer of the sacrifice—the one who makes the offering—obtains offspring, cattle, food, wealth, and the lustre of Brahman. The second oblation is "To vyan, hail!" Through this offering, vyan becomes satisfied, along with the moon, the directions of space, and the deities presiding there. The sacrificer thereby gains the aforementioned enjoyments and liberation, and becomes utterly content. The third is "To apan, hail!" When apan is satisfied, speech, fire, earth, and the beings dwelling in these realms are satisfied; the sacrificer too obtains the aforementioned contentment. The fourth oblation is "To saman, hail!" When saman is satisfied, the mind and the lightning corresponding to it, along with the beings in that sphere, are satisfied; the sacrificer is likewise satisfied as before. The fifth is "To udan, hail!" Through the satisfaction of udan, the skin, air, space, and the beings dwelling therein are satisfied. As a result, the sacrificer becomes worthy of enjoying cattle and other objects, and of attaining the knowledge of Brahman—the ultimate liberation.
These are the five oblations to the vital force. Through these oblations, a person is freed from suffering, poverty, want, complaint, disease, sorrow, and torment. And there is no doubt that as the ultimate fruit, the path to liberation becomes accessible to one.
From the vital force alone do the senses originate—the vital force is their root. Now I shall explain how the vital force, assuming different names and forms, manifests itself through the ten senses—five organs of action and five organs of knowledge—and what their functions are:
The five sense organs: the eye perceives, the ear hears, the nose smells, the tongue tastes, and the skin feels. The five organs of action: the hands, the feet, the anus, the penis, and the bladder. When external objects must be obtained, the hands acquire them—as in taking food, grasping material things, or pursuing learning. The feet travel and bear the body's weight. The anus expels waste and the downward-moving breath. The penis maintains the balance of semen and vital air. The penis discharges the body's liquid waste and serves generation.
These matters, taken together with the ten organs, give rise to the mind's manifestations—what we call the six enemies. The six enemies are: desire (sensory pleasure, craving, and longing), anger (rage, born from desire's frustration), greed (the character's affliction, pointing to any form of lust, avarice, or attachment to sensible objects), delusion (the enemy that confounds), pride (mental restlessness, arrogance, or intoxication with the self), and envy (malice or jealousy—clinging to one's own possessions and material goods even while unable to enjoy them, and unwilling to share with others).