Recent years have seen considerable progress in the understanding of pathophysiological and pathobiological aspects of pulmonary arterial hypertension (PAH): a vasculopathy resulting in a progressive obliteration of the small pulmonary artery, progressing to right heart failure and death. PAH-specific drug therapies target the discovered pathophysiological pathways and aim to improve hemodynamics and increase exercise capacity, both major prognostic factors. PAH needs to be distinguished from the other causes of pulmonary hypertension (PH) due to left heart disease, lung disease or chronic thrombo-embolism (CTEPH). Here, the treatment must target the underlying cause. Nevertheless, the survival improvement in the modern management era is still unsatisfactory and PH outcome, whatever the cause, remains poor. This implies that PH should undergo a comprehensive diagnostic workup and be managed with ambitious goal-oriented strategies. Supervised exercise training has also recently been considered as of interest in these strategies where treatment goals rely mainly on clinical evaluation, exercise capacity and hemodynamic parameters. Hence, new tools allowing early diagnosis and unmasking new criteria of disease severity and response to treatment are needed in PH management. This is particularly true in PAH and CTEPH. In this line, innovative and non-invasive exploration of cardiodynamic response to exercise may reply to several unmet need. For instance, exploration of pulmonary circulation and hemodynamics during exercise may help diagnostic workup and guide therapeutic strategy. The aims of the present thesis are i) to demonstrate how physiological explorations in healthy subjects may allow a better understanding of the consequence of hemodynamic impairment on exercise response and ii) to explore the ability of non-invasive techniques to help physician for hemodynamic evaluation in pulmonary hypertension.