The ancient scriptures of yoga define and mention many different pranayama techniques.
Patanjali Yoga Sutra 2.49 defines pranayama as:
तस्मिन् सति श्वासप्रश्वासयोर्गतिविच्छेदः प्राणायामः॥४९॥
“Tasminsati shwasaprashwasayorgativicchedaha pranayamaha” (II. Sutra 49)
“In that state of being in asana or posture, breaking the (usual) movement of inhalation or exhalation is regulation of breath.”
Simply put, ‘prana’ refers to the universal life force and ‘ayama’ means to regulate or lengthen.
In ancient Indian system of yoga prana is identified as the universal life force or energy which distinguishes the living from the dead. This life force energy flows through thousands of subtle energy channels called ‘nadis’ and energy centers called ‘chakras.’
It was discovered that the quantity and quality of prana and the way it flows through the nadis (subtle energy channels) determines one’s state of mind.When the prana level is high and its flow is continuous, smooth, and steady, then the mind is calm, happy, positive, and enthusiastic.
Pranayama is not just breath control as commonly perceived but it is the control of prana through the breath. These techniques involve breathing through the nostrils in a specific pattern of inhalation, breath retention, exhalation. Practiced correctly, under the right supervision, pranayama brings harmony between the body, mind, and spirit, making one physically, mentally, and spiritually strong.