Kapalabhati is a yogic breathing technique. Kapala means the skull. Bha in Sanskrit ‘means to shine.’ Kapalabhati is a breathing technique but not a variant of pranayama. It is counted as one among the six cleansing acts (Shuddhi Kriyas) of hatha yoga. It is sometimes mistakenly called bhastrika, due to its resemblance to a bellow’s action, which is called bhasra in Sanskrit. Bhastrika is actually a variant of pranayama, which includes, in addition to kapalabhati, deep breathing and holding of the breath (kumbhaka).
Kapalabhati consists of rapid incessant breathing in a sitting position. The lotus pose (padmasana) is preferred, as the foot-lock in it is quite tight and strong enough to sustain the incessant movements of the abdominal wall. Air is expelled through both the nostrils, 100 to 120 times per minute. Unlike normal breathing, kapalabhati has an active expiration and passive inspiration. By a sudden contraction and backward thrust of the abdominal wall just below the navel, which pushes the thoracic diaphragm upward, the lungs are squeezed slightly, expelling large amount of air. Soon afterwards the abdomen is relaxed, the diaphragm goes down and the lungs are passively filled with large amounts of air. There is no holding of breath in kapalabhati.
In one round of kapalabhati, twenty to two hundred incessant expirations may be performed, increasing the number with practice. Later on, a second and a third round may be had with a few normal respirations in between for rest. This increases the lung ventilation per minute by expelling additional carbon-dioxide from the blood. One can do kumbhaka for a longer time after kapalabhati.