The authors assessed airway impedance responses to psychological stressors among 113 individuals: 61 with asthma only (AS), 10 with asthma and panic disorder (ASPD), 24 with panic disorder only (PD), and 18 controls with neither condition (CON). Individuals with either AS or PD were affected by psychological stressors as measured by the forced oscillation technique. Individuals with PD (with or without AS) displayed lower airway impedance than those without PD. These data suggest that the airways of individuals with PD are in a chronic state of preparedness, which may promote hyperventilation.