Bastrika is one of pranayamas (breathing exercises) in Hatha Yoga. Bastrika means belows breath in Sanskrit. If you do Bastrika very vigorous and intensive, you will have no stress in just 3 minutes. But be careful, it’s very powerful and it’s better to increase intensity gradually starting from 30 seconds. Here is the description by Svami Sivanada:
Inhale and exhale quickly ten times like the bellows of the blacksmith. Constantly dilate and contract. When you practise this Pranayama a hissing sound is produced. The practitioner should start with rapid expulsions of breath following one another in rapid succession. When the required number of expulsions, say ten for a round, is finished, the final expulsion is followed by a deepest possible inhalation. The breath is suspended as long as it could be done with comfort. Then deepest possible exhalation is done very slowly. The end of this deep exhalation completes one round of Bhastrika.
Benefits: Bhastrika Pranayama refreshes body and mind. It has a regenerating and rejuvenating influence upon the whole body and improves memory. The increased blood supply to the head improves eyesight and hearing. The lungs are strengthened and it is beneficial for bronchitis, as the respiratory system is quickly and deeply purified. Digestive function is stimulated, improving metabolism.
Contraindications: Do not practice Bhastrika if you’re pregnant, have uncontrolled hypertension, epilepsy, seizures, or panic disorder. You should also avoid practicing bellows breath on a full stomach. Wait at least two hours after eating.