The diaphragm flattens out and pulls forward, drawing air into the lungs for inhalation. During exhalation the diaphragm expands to force air out of the lungs. Adults normally take 12 to 20 ...

It also looks at lung function and the processes of inhalation and exhalation. Forming the main external opening of the respiratory system, the nose protects the anterior portion of the nasal cavity.

(1:2 ratio) Box breathing: Emphasizes equal duration of inhalation, breath retention, and exhalation. (1:1:1 ratio) Cyclic hyperventilation: Emphasizes robust inhalation, short retention ...