4th Limb of Yoga- Prananyama
(refinement of breath/life force)

"Through the steady rhythm of inhalation and exhalation, the air and prana circulate within and between the physical and subtle bodies" p. 233

It is said there are three main energy channels in the body though which prana flows: ida, pingala, and shushumna nadi.  When the first two are balanced, latent energy can travel up through the central channel (shushumna), which leads to deeper states of consciousness.

Refinement of the breath creates an environment for meditation.  Meditation leads to deeper states of consciousness.

Together with asana and relaxation, pranayama is an essential component of Hatha yoga.

"With rhythmical breathing, we align and "comb" the energy; it becomes smoother, calmer, and more focused.  The focused energy then acts like a magnet, attracting like polarities to us" p.235

"Asana steadies the body; pranayama aligns the mental and emotional patterns.  We will then guide the senses through pratyahara, allowing us to focus and dive deep within" p.238

The yoga sutras say pranayama "lifts the veils covering the inner light". Our true selves are revealed as the prana in the body is enhanced/guided/refined.  Things have prana.  The ocean, for example, has a lot of prana.  Prana is life force.

quotes taken from The Secret Power of Yoga, by Nischala Joy Devi