Cardiopulmonary exercise testing (CPET)
To evaluate exercise capacity, a treadmill (Technogym Run Race 1400HC) maximum test was performed. The protocol started with an initial speed and slope of 2.5 km h−1 and 0.5%, respectively. Increases in both variables of 0.1 km.h−1 and 0.5%, respectively, were used every 15 s. Gas exchange data were measured breath‐by‐breath using open‐circuit spirometry (Vmax 29C; Sensor Medics). The variables collected included VO2peak, maximum minute ventilation (VE), respiratory exchange ratio (RER), VE/VO2, VE/VCO2, BR, peripheral oxygen saturation (SpO2), and maximum heart rate (HRmax). HRmax was measured using a heart rate monitor (Polar®) and SpO2 was monitored with a pulse oximeter (TrueSatTM, GE Healthcare, Finland). VO2peak was recorded as the highest value obtained for any continuous 20 s period. The ventilatory threshold (VT1) was determined using the criteria of an increase in both the VE/VO2 and end‐tidal pressure of oxygen, with no increase in the VE/VCO2. BR was calculated as the difference between MVV and the maximum ventilation at peak exercise. An indirect estimate was used to predict MVV by multiplying FEV1 by 35. The test was considered as maximum if the following criteria were met: (i) heart rate greater than 180 beats per minute, (ii) respiratory exchange ratio above 1.0, and (iii) clear exhaustion according to the perceived exertion (RPE).