ujjayi pranayama

Is one of the 8 types of pranayama described in the Hatha Pradipika by Svatmaram (2:51-53):

• (2:51) Having close the opening of the Nadi (larynx),  the air should be drawn in such a way that it goes touching from the throat to the chest, and making noise while passing.
• (2:52) It should be restrained, as before, and then let out through Ida (left nostril). This removes slesma (phlegm) in the throat and increases the appetite.
• (2:53) It destroys the defects of the nadis, dropsy and disorders of Dhatu (humours). Ujjayi should be performed in all conditions of life, even while walking or sitting.

Due to the partial closure of the glottis during puraka and during rechaka, Ujjayi has the characteristic of produce an audible hissing sound.

At the beginning the practitioner can resort to only puraka and rechaka phases in the ratio of 1:2 along with the distinctive sound; then with the practice the kumbhaka is introduced gradually in the form of a short pause between puraka and rechaka. 

A practice of Ujjayi pranayama without kumbhaka has been found to relieve depression. The practitioner feels energetic and vitalized immediately after doing this pranayama (Gore M. M., 2005, Anatomy and Physiology of Yogic Practices).