Inhalation and exhalation are both done through the nose. The "ocean sound" is created by moving the glottis as air passes in and out. As the throat passage is narrowed so, too, is the airway, the passage of air through which creates a "rushing" sound. The length and speed of the breath is controlled by the diaphragm, the strengthening of which is, in part, the purpose of ujjayi. The inhalations and exhalations are equal in duration, and are controlled in a manner that causes no distress to the practitioner.