The most essential change of respiratory physiology are: dilatation of alveoli, enlargement of air space, decrease gas exchange surface area, loss of supporting tissue for distal airway (senile emphysema), decrees of chest wall compliance and decrease of respiratory muscle strength. These changes leading to decrease lung elastic recoil, increase residual volume and functional capacity, and increase work of breathing at rest. In addition, such changes affect respiratory function, especially dynamic hyperinflation (DH) development which could be one of the factors relate to dyspnea during exercise in aging Positive expiratory pressure (PEP) therapy for DH treatment during exercise was reported in several studies.