Fig. 1. Delta maximum decrease for FEV1 (A), FVC (B), FEF25-75 (C), and FEF50 (D) at GXT (ambient laboratory temperature 23℃; relative humidity 50%), 0℃, -5℃, -10℃, -15℃, and -20℃ (relative humidity 40%). FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; FEF25-75, forced expiratory flow at 25%-75%; FEF50, forced expiratory flow at 50%; GXT, graded exercise test.
