Will be collected clinical and anthropometric data of the participants and they are packaged in self-evaluation form. Evaluation of pulmonary function at rest will be rescued from patient charts. When carried out for over six months, will be repeated by the researchers. Patients will conduct incremental CPET of 5-10W/min limited by symptoms (FEV1 <1L-5W or FEV1> 1L-10W) (Visit 1). After a period of 2-7 days the CPET will be performed submaximal with 75% of the peak load reached in the incremental CPET (visits 2-3). During the visit without EPAP will be maintained using the facial mask applied without resistance.

Will be collected clinical and anthropometric data of the participants and they are packaged in self-evaluation form. Evaluation of pulmonary function at rest will be rescued from patient charts. When carried out for over six months, will be repeated by the researchers. Patients will conduct incremental CPET of 5-10W/min limited by symptoms (FEV1 <1L-5W or FEV1> 1L-10W) (Visit 1). After a period of 2-7 days the CPET will be performed submaximal with 75% of the peak load reached in the incremental CPET (visits 2-3). The application of EPAP (10cmH2O) via face mask (Vital RHDSON Signs®, New Jersey, USA) will be randomized with the help of opaque envelopes to be given in one visit. IC serial measurements will be carried out before, during and immediately after the exercise.

The expiratory positive pressure is applied through silicone mask (RHDSON Vital Signs®, New Jersey, USA) containing one-way valve and a resistance mechanism expiratory positive expiratory pressure generator adjustable 5-20 cm H2O (Spring Loaded) (Vital Signs® , New Jersey, USA). The mask one headgear will be comfortably adjusted to face being used to prevent air leakage, and the pressure level gradually adjusted to the level of 10 cm H2O.

This technique assumes that the TLC remains unchanged during exercise, even in patients with COPD: thus, changes in IC will reflect in proportional changes in end-expiratory lung volume (EELV). The validity, reproducibility and sensitivity to these interventions have been demonstrated by this technique in patients with COPD, showing a variety of functional abnormalities.

Before the test, the patients will be familiar with this technique by performing IC maneuvers. They will be instructed to breathe normally during exercise and then, through verbal commands, will conduct a deep breath followed by a relaxed expiration. During inspiration, patients will be encouraged to make every effort.

IC maneuvers are performed during the rest period are obtained until at least two reproducible efforts, namely within 10% of the highest acceptable value. After that, measurements of IC will be held every two minutes until exhaustion.

To assess exercise tolerance we will compare the final time the two submaximal CPET (with EPAP and without EPAP). In each test, the patient will be encouraged to achieve maximum tolerance and will be instructed to stop the test in the exhaust.