Bhastrika is an important pranayama. A large amount of prana vayu is supplied to the body by this pranayama and at the same time impure air (carbon dioxide) is driven off the body and blood is purified.

Bhastrika means bellows. Its working is similar to that of the bellows of the blaksmith. Hence the name. Ida, pingala and sushumna, all the three nadis are influenced by it.

Caution: Those sufferings from high and low blood pressure and the ailments of the heart and the lungs should not do it.

Technique

Sit in Padmasana and make the body erect. Make the mind thought-free and relaxed. Now close the right nostril with your right thumb, inhale and exhale with full force. First do this slowly, then increase your speed and do it quickly for about 20 times. In the end, inhale fully, close the left nostril with your third finger, and perform all the three Bandhas. increase the Kumbkaha according to your capacity. Now open the Bandhas slowly, lift the thumb from the right nostril and exhale through it slowly. Relax for a moment. 

Repeat this process by closing the left nostril.

Now place your hands on your knees and do Bhastrika with both nostrils simultaneously. Do it slowly; increase your speed with practice.

It should be remembered that in this Pranayama, the rhythm in exhaling and inhaling should be maintained ,and the time of inhaling should be equal to the time of exhaling .the Pooraka and rechaka ,both are done with full and equal force and no pressure is exerted on the openings of the nostrils in both the state.

Before doing Bhastrika the practice in contracting and expanding the belly without moving any other limb is necessary. Such as a practice brings efficiency in this pranayama. bhastrika, when done through the left nostril, influence the Ida.When done through the right nostril, it affects the Pingala and when done through both the nostrils,it effects the sushumna.These are respectively called Chandrang Bhastrika,Suryang Bhastrika and Sampoornang Bhastrika, helps to strengthen the central nervous system, the memory power. 

By doing Bhastrika correctly, the Prana gets stability, the mind is brought under control, indolence is removed and Dhayana becomes easier.