Cardiopulmonary exercise testing is an active research area in patients with unexplained dyspnea, heart failure, and pulmonary hypertension. Focus has centered on the use of novel hemodynamic parameters to further characterize these disease states, influence therapeutics, and determine prognosis. Translational research focuses on the underlying cardiopulmonary physiology to more precisely quantify the effect of pulmonary vascular disease on the right ventricle and pulmonary function/hemodynamics. In addition, phenotyping unexplained dyspnea is of critical importance, given the significant heterogeneity of this patient population with implications for therapies and clinical trial design.