Pranayama _B.K.S Iyengar
“Prana means energy. Cosmic energy, individual energy, sexual energy intellectual energy, all are prana.It is even said that prana causes sun and the rain to come.Prana is universal. It permeates each individual as well as the universe at all levels. All that vibrates is prana-heat, light, gravity, magnetism, vigour, power, vitality, electricity, life, breath, spirit, all are forms of prana.Prana is the hub of the well of life. All beings are born through it and live by it, and when they die, their individual breath dissolves into the cosmic breath. It is potent in all beings and is a prime mover of all activity.”
Prana and consciousness are in constant contact with each other.They are like twin brothers. It is said in yoga texts that as long as the breath is still, prana is still, and hence the mind is still.All types of vibrations and fluctuations come to a standstill when prana and consciousness are quiet, steady and silent.Knowing this connection between breath and consciousness, the wise yogis of India advocated the practice of pranayama, which is the very heart of yoga.