During which type of breathing is inhalation considered active and exhalation passive?

• A. Controlled breathing
• B. Tidal breathing
• C. Deep breathing
• D. Forced expiration

Answer: (B)

Inhalation during tidal breathing is considered active because it involves the contraction of the diaphragm and intercostal muscles, which increases the volume of the thoracic cavity and allows air to flow into the lungs. This active process requires muscular effort to draw air in. On the other hand, exhalation during tidal breathing is primarily passive, relying on the elastic recoil of the lungs and the relaxation of the diaphragm and intercostal muscles, leading to a decrease in thoracic volume and enabling air to be expelled without the need for muscular effort.

In contrast, controlled breathing often involves a conscious effort to manage both inhalation and exhalation, making both phases more active. Deep breathing, also known as diaphragmatic breathing, actively engages the diaphragm for inhalation but can also involve active control during exhalation. Forced expiration, typically used in activities requiring a strong expulsion of air (like singing or shouting), actively engages the abdominal muscles to push air out, making both inhalation and exhalation active processes. Therefore, tidal breathing is unique in distinguishing inhalation as active and exhalation as passive.