Chapter 51, Problem 3.1CT

To determine possible obstruction of the airway, a forced expiratory volume (FEV) may be measured using a spirometer. Under normal circumstances, a healthy adult can expel 75% to 85% of the vital capacity in 1.0 second $\left({\text{FEV}}_{\text{1}}\right)$ . Predict how this would change in a person who has asthma, and explain your reasoning.