What is forced expiratory volume?

What is forced expiratory volume?

• A. Volume of air exhaled during forced expiration.
• B. Volume of air expired per second during forced expiration.
• C. The total air exhaled during a forced expiration.
• D. The amount of air exhaled in one breath during quiet breathing.

Answer: (B)

Forced expiratory volume measures how much air you can blow out in a specific interval during a forced expiration. In spirometry, you take a maximal inhale and then exhale as forcefully and quickly as possible; the key value is the amount you exhale in the first second, which is the usual measure of forced expiratory volume. This per-second rate is what makes it distinct from the total air expelled during the entire forced maneuver, which is called the forced vital capacity. The other option describes tidal volume—air exhaled in a normal breath during quiet breathing. So the best answer captures the amount of air expelled per unit time (per second) during a forced expiration.

Forced expiratory volume measures how much air you can blow out in a specific interval during a forced expiration. In spirometry, you take a maximal inhale and then exhale as forcefully and quickly as possible; the key value is the amount you exhale in the first second, which is the usual measure of forced expiratory volume. This per-second rate is what makes it distinct from the total air expelled during the entire forced maneuver, which is called the forced vital capacity. The other option describes tidal volume—air exhaled in a normal breath during quiet breathing.

So the best answer captures the amount of air expelled per unit time (per second) during a forced expiration.