Cardiopulmonary changes in PH are considered the main limiting factor, however, it is known that the muscular alterations potentiate the symptomatology. Several HP factors and mechanisms have an impact on peripheral and respiratory muscle changes, such as: decreased cardiac output, hypoxemia, inflammation, increased insulin resistance, altered autonomic nervous system (ANS) response, and muscle disuse. These factors imply alteration of fiber type, atrophy, capillary vascular reduction, reduction of oxidative capacity, endothelial dysfunction and decreased muscle excitability by ANS.