Sectional breathing is a yogic practice

Abdominal breathing or adhama svasa: Sit in comfortable position with spinal cord erect. Vajrasa is the recommended posture. Exhale and inhale completely, slowly and continuously. Now, breath in, this is called puraka. The abdomen is made to bulge continuously with air entering especially into the lower sections of the lungs. Before exhaling stop the breath(Antarya kumbhaka) for a few seconds without any force. While exhaling (Recaka) the abdomen is drawn inwards continuously and slowly. Before the breath is reversed, stop the breath(bahya kumbhaka) effortlessly for few seconds and then inhale. Repeat the breathing cycle. The lower lobes of lungs are opened up fully by this type of breathing.

Chest breathing or Madhyama Svasa: This sectional breathing is also similar to the above and to be performed by sitting erect in Vajrasana. Inhalation and exhalation is performed by expanding and contracting the chest only. Air flows through both the nostrils slowly and continuously. The abdomen is controlled to avoid bulging out. The middle lobes are opened up fully by this type of breathing.

Clavicular breathing or Adya Svasa: This is also a repetation of the above. Sit erect in Vajrasana. Raise the collar bones while inhaling and move the shoulder backwards slightly while exhaling. Keep the abdominal muscles contracted. The air is forced into the uppermost regions of the lungs thus ventilating the upper lobe while exhaling bring down the collar bones and shoulders forward to normalcy. This exercise requires only half the number of times the other two exercises are performed.