Kapalabhati Pranayama, the “Skull Shining” or “Skull Polishing” breath,
also known as Vatakrama, energizes the cranium and abdomino-pelvic cavity, increasing pranic pressure in both, reducing mucus and reducing discursive thoughts, improving focus and wakefulness in meditation and meditative absorption, improving dedication to intentional living and practice, and allowing for longer periods of meditation without drowsiness. It is often done at the beginning of practice, after warming kriyas, eye exercises, and nostril clearing, and before or after Suryanamaskar, and before longer asana holds and more coplete kriya practices.
The practice of Vatakrama / Kapalabhati Pranayama is typically done in 3 rounds of 21 to 108 exhalations, followed by a full slow exhalation and retention without breath, followed by a full yogic complete breath.
Uddiyana Bandha and/or Nauli Kriya can be performed during the retention without breath.