Bhastrika (bellows breath) is a heating and stimulating pranayama that involves moving the diaphragm similar to when pumping bellows to stoke a fire. The technique involves quick abdominal (diaphragmatic) breathing so the student should be familiar with this type of breathing before they start.
In contrast to kapalbhati (another abdominal breathing technique), which uses passive inhalation and active exhalation, bhastrika has both active inhalation and active exhalation. Also, in contrast to kapalbhati, which does not include breath holding, bhastrika (when performed fully) includes breath holding as well as bandhas (body locks).
When doing bhastrika pranayama, it is important to take your time and not to rush.
Technique
The following bhastrika technique overview is for beginners and so does not involve breath holding or bandhas.
Sit comfortably with your back straight. Rest the hands on the knees with palms facing down or up and, if you wish, you can touch the index fingers and thumbs on each hand (Jnana mudra).
Close your eyes. All breathing is through the nose.
Take two full and complete yogic breaths. On the third inhale, breathe in to the abdomen by pushing the diaphragm down and expanding the abdomen – don’t inhale to the chest/thoracic region. Once the abdomen is full, exhale by pulling in the diaphragm up and the abdomen inwards. Both inhalation and exhalation should be forceful but you should not strain. Only the abdomen should be moving. The rest of the body should be still and relaxed.
To begin with, do 10 breaths (1 breath every 2 seconds) and then relax and breathe normally for 30 seconds or so.
Do another 4 rounds of 10 breaths.
If during the practice you feel faint, sick, or start sweating excessively you should stop.
Contraindications
You should not practice bhastrika pranayama if you have high blood pressure, heart disease, hernia, vertigo, glaucoma, retinal problems, epilepsy, gastric ulcer, or have had a stroke.