RESEARCH ARTICLE s a

Pulmonary arterial hypertension (PAH) is characterized by changes in mostly the distal pulmonary arteries. This causes an increase in pulmonary vascular resistance, which in turn restricts the blood flow through the pul-monary circulation [1,2]. In order to maintain the blood flow, the pulmonary artery pressure increase which leads to right ventricular overload, hypertrophy and dilatation [1]. The physiologic response of the pulmonary vascula-ture to exercise is different from normal in individuals with PAH and they generally show a reduced exercise capacity [3]. Advances in the understanding and manage-ment of pulmonary arterial hypertension have enabled earlier diagnosis and improved prognosis. However, des-pite best available therapy, symptoms of exertional dys-pnea and fatigue are commonly reported and result in a reduced capacity to perform daily activities and impaired quality of life. Exercise training has demonstrated efficacy in individ-uals with other respiratory and cardiovascular diseases [4-7]. Historically, however, exercise training has not been utilized as a form of therapy in PAH due to the perceived * Correspondence