Question

Pressure between the inside chest wall and the outside of the lungs normally remains negative. Explain how pressure inside the lungs can become positive (to cause exhalation) without muscle action.

Answer 1

Answer:

by doing rapid shallow breathing and pursed lip breathing  

Explanation:

Pressure with in the chest wall and the outside of the lungs remains negative because the intrapleural pressure is always lesser than the intra-alveolar pressure or atmospheric pressure. In general forced expiration leads to an increasing positive pressure in pleura. This happens because the pleura airway gets compressed and the size of airway reduces thereby forcing expiration.  

People who are able to resist airway can increase airflow by doing rapid shallow breathing and pursed lip breathing