Relationship between the postbronchodilator forced expiratory volume at 1 second (FEV<sub>1</sub>) (A), the respiratory resistance at 5 Hz (R5) (B), the difference of the respiratory resistance at 5 Hz and 20 Hz (R5-R20) (C) and the reactance at 5 Hz (X5) (D) with the physical component summary of the SF-12 questionnaire in all study subjects.

<p>Relationship between the postbronchodilator forced expiratory volume at 1 second (FEV<sub>1</sub>) (A), the respiratory resistance at 5 Hz (R5) (B), the difference of the respiratory resistance at 5 Hz and 20 Hz (R5-R20) (C) and the reactance at 5 Hz (X5) (D) with the physical component summary of the SF-12 questionnaire in all study subjects.</p>