In Kapalabhati, Rechaka is done with full force. The attention of the practitioner should be fixed on Rechaka during the process. When the breath is exhaled with full force, the stomach should be squeezed inwards, so that the abdominal gas is thrown out with a jerk. In the Pooraka state, the belly regains its original position.
Sit comfortably in Padmasana or Siddhasana and normalise your breath. try to throe your breath out through your nose with force. First do it slowly and then increase your speed . Do not make any effort to inhale. It is to be stressed that the breath has only to be thrown out and all effort should be directed towards that end. At the start, do it for 15 to 20 times. The practice can be increased to 50-60 times, but should be increased gradually. Also increase your practice according to your capacity. After doing the pranayama, perform the three bandhas(the moola bandha, the jalandhar bandha and the uddiyan bandha)for a few moments while doing bahya kumbhaka. After that, remove the bandhas and normalise your breath.
Kambhaka increase the power of concentration by removing impurities from the nerves of the skull region. Those who sit in dhyana should first do kapalabhati. This helps to control the sense organs and keeps the mind at rest.