- Protocol for cardiopulmonary exercise test. Tests will be performed and evaluated according to current European Society of Cardiology guidelines (Eur J Cardiovasc Prev Rehabil 13:150-164 2006; Eur J Cardiovasc Prev Rehabil 2006; 13:300-311). All tests will be performed using the same cyclo-ergometer (Ergometrics 100, Ergoline, Bitz, Germany)and metabolic cart (Oxycon Mobile software v. 4.6, VIASYS Healthcare GmbH, Wurburg, Germany). The exercise protocol will include 10 minutes of monitored sitting rest, followed by 3 minutes of unloaded pedalling and by 30 W load increments every 2 minutes up to exhaustion. Breath-by-breath ventilation, respiratory gases, one-lead ECG and pulse oxymetry (SpO2) will be recorded throughout each test. Arterial blood pressure will be measured by a mercury sphygmomanometer in duplicate at the end of the resting phase and of each 30 W step, and at peak exercise. Cardiopulmonry exercise tests will be blindly and independently evaluated by two expert readers. The anaerobic threshold will be identified by the standard technique (Wasserman K. Breathing during exercise. N Engl J Med 1978; 298:780-785. VE/VCO2 slope will be calculated as the slope of the linear relationship between VE and VCO2 measured up to the respiratory compensation point.