[Sports fitness in pulmonary hypertension]

In patients with pulmonary hypertension caused by a large ventricular septal defect, the cardiopulmonary performance capacity (CPC) depends on the relation of pulmonary to systemic vascular resistances. Changes in this relation occurring on exercise are mainly due to an exercise - induced fall of the systemic vascular resistance. If the ratio of pulmonary to systemic resistance is below 1 at maximal exercise, the CPC is reduced as a result of the left to right shunt. In case of a pulmonary to systemic resistance ratio of higher than 1 at maximal exercise hypoxemia will be a limiting factor. Only in cases of a moderate degree of pulmonary vascular changes, resulting in a relation of resistances at maximal exercise in the range of 1, will the CPC be normal. Patients with primary pulmonary hypertension always present with reduced CPC as a main symptom. Cardiac output cannot be adequately increased during exercise. Only by excessive peripheral oxygen desaturation can a certain adaptation to the oxygen demand of the exercising organism be possible to a certain degree, though only at low work rates. Uneven perfusion and the corresponding ventilation-perfusion inequality are only moderate. However, due to the widened arterial-venous oxygen difference, ventilation-perfusion inequality with its distinct alveolar-arterial oxygen pressure difference can result in a considerable degree of venous admixture. In adolescents, pulmonary hypertension caused by obstructive lung disease is seen almost only in patients with advanced stages of cystic fibrosis. It is then combined with increased venous admixture, and often with CO2-retention.(ABSTRACT TRUNCATED AT 250 WORDS)