The lung vital capacity (VC) will be unaffected, because vital capacity measurement is not a timed measurement. Vital capacity is basically proportional to the number of lung alveoli possessed by an individual. Forced expiratory volumes (FEV1.0,FEV2.0) will be decreased, because airway narrowing with asthma impedes airflow. The FEV measurements represent the percent of the vital capacity that can be expired forcefully and rapidly in a given period of time, such as 1 second for the FEV1.0 (Figure 23.1)