Cardiopulmonary exercise testing
The CPX was performed on an electromagnetic cycle ergometer (Medfit 400L, Medical Fitness Equipment, Maarn, Netherlands), following a ramp protocol, with a speed of 60 revolutions per minute (rpm) and workload increments from 10w to 20w per minute, until achieving physical exhaustion. Participants were connected to a ventilator (SensorMedics Corp, CA, USA), and pulmonary ventilation, oxygen (O