What is tidal volume?

What is tidal volume?

• A. Amount of air exhaled after normal inspiration
• B. Amount of air inhaled after normal exhalation
• C. Total air in lungs
• D. Residual air after exhalation

Answer: (A)

Tidal volume is the amount of air moved during a normal, quiet breath. In a resting adult, this is about 500 mL. Saying it’s the air exhaled after a normal inspiration captures the idea that the same volume of air that is inhaled in a typical breath is then exhaled in that breath’s expiration. It’s not the total air in the lungs (that’s total lung capacity) and not the air left after you exhale (that’s residual volume). It’s the volume you breathe in and then out in a single normal breath.

Tidal volume is the amount of air moved during a normal, quiet breath. In a resting adult, this is about 500 mL. Saying it’s the air exhaled after a normal inspiration captures the idea that the same volume of air that is inhaled in a typical breath is then exhaled in that breath’s expiration. It’s not the total air in the lungs (that’s total lung capacity) and not the air left after you exhale (that’s residual volume). It’s the volume you breathe in and then out in a single normal breath.