Breath in and you will feel how relaxed you become.

Pranayama (Prāṇāyāma) is the practice of breath control in yoga. In modern yoga as exercise, it consists of synchronising the breath with movements between asanas, but is also a distinct breathing exercise on its own, usually practised after asanas.

Kapalabhat, also called breath of fire, is an important Shatkarma, a purification in hatha yoga. The word kapalabhati is made up of two Sanskrit words: kapal meaning 'skull', and bhati meaning 'shining, illuminating'. The organs in and under the skull, mainly the brain, small brain and any of the spaces inside the head that are connected to the back of the nose, are influenced in a good manner.

One should know how to do Kapalabhati Pranayama in a proper manner. It is intended mainly for cleaning the cranial sinuses but has many other effects including curing anemia, according to the Gheranda Samhita and other sources.

The Technique of Kapalabhati involves short and strong forceful exhalations and inhalation happens automatically. There are three forms of Kapalabhati:

Vatakrama kapalabhati, a practice similar to the Pranayama technique of Bhastrika, except that exhalation is active while inhalation is passive, the opposite of normal breathing.
Vyutkrama kapalabhati, a practice similar to Jala neti, it involves sniffing water through the nostrils and letting it flow down into the mouth, and then spitting it out.
Sheetkrama kapalabhati, can be considered the reverse of Vyutkrama kapalabhati, in which water is taken through the mouth and expelled through the nose.