Pranayama: The Science of Breath Control

प्राणायाम प्राणायामः

The systematic practice of regulating life energy through conscious control of breath, forming the bridge between physical postures and meditative states in classical yoga.

THE DEFINITION AND PRINCIPLES OF PRANAYAMA

Classical definitions and fundamental theories of breath control.

Classical Definition
प्राणायाम
prāṇāyāma
Extension and control of life energy.
Prāṇa (life force) + āyāma (extension, control). The conscious regulation of breath through interruption (vicchedaḥ), prolongation (dīrgha), and refinement (sūkṣma) of breathing patterns.
Patañjali's Definition
तस्मिन् सति श्वासप्रश्वासयोर्गतिविच्छेदः प्राणायामः
tasmin sati śvāsa-praśvāsyor gati-vicchedaḥ prāṇāyāmaḥ
When posture is steady, the conscious interruption of the natural flow of inhalation and exhalation is prāṇāyāma.
Yoga Sūtra 2.49. Prāṇāyāma begins only after āsana is stabilized. It involves conscious intervention in the automatic breathing process.
The Three Modulations
बाह्याभ्यन्तरस्तम्भवृत्तिः देशकालसंख्याभिः परिदृष्टो दीर्घसूक्ष्मः
bāhyābhyantarastambhavṛttiḥ deśakālasaṃkhyābhiḥ paridṛṣṭo dīrghasūkṣmaḥ
Prāṇāyāma has external (exhalation), internal (inhalation), and suspended (retention) movements. Regulated by place, time, and count, they become prolonged and subtle.
Yoga Sūtra 2.50. The three components are regulated progressively through spatial awareness (deśa), timing (kāla), and numerical count (saṃkhyā).
The Four Components
छेदनं पूरकं कुम्भकं रेचकं प्राणायामः
chhedanaṃ pūrakaṃ kumbhakaṃ recakaṃ prāṇāyāmaḥ
Purification, inhalation, retention, and exhalation constitute prāṇāyāma.
Haṭha Yoga Pradīpikā 2.1. The complete process includes preparatory cleansing, followed by the three main phases of breath control.