Pranayama is the expansion of prana and also the conscious control of breath. It is the most important practice of Yoga, for the breath is the most important source of energy.
It is the most direct path to the awakening of Kundalini energy, the energy which is with no exception given to each and everyone. Yet that energy is waiting to be awaken.
Today it is common to use the term pranayama as breathing techniques but the yogic breathing techniques actually expand the individual vital energy what the meaning of pranayama is.
Thoughts, or mind waves, reflect the breathing. When the mind is unsettled the breathing is irregular, rapid and shallow, when the mind is relaxed the breathing is slow and deep. And vice versa, controlling the breath one can control the mind bringing it to complete stillness. This tranquil state of shakti or life force is called shanta which is a great power full of life, since the power lies in a tranquility and not in a rush.