Pulmonary hypertension (PH) is a chronic, debilitating condition which gravely affects exercise tolerance and quality of life. Though most therapies focus purely on medical intervention, there is a growing body of evidence to suggest the role and benefits of exercise training. This chapter discusses the various physiological basis for exercise intolerance observed in PH and highlights the rationale for exercise training. Recent evidence related to exercise training is summarized and potential pathways to suggest adaptations to exercise training are put forward. While keeping the paper applicable to clinicians, details on evaluating exercise intolerance, prescribing exercise and setting up rehabilitation centers for PH are discussed.