BACKGROUND: The prognosis of Pulmonary Hypertension (PH) is directly correlated with the functional capacity (FC). The most common FC test is the 6-Minute Walk Test (6MWT), however, there is evidence to suggest that the 6MWT does not reflect the real FC in PH patients. AIM: To compare physiological responses among three field walk tests and cardiopulmonary exercise testing (CPET) in patients with pulmonary hypertension (PH), and to determine the determinants of distance walked in the field walk tests. DESIGN: Cross sectional study. SETTING: Outpatient clinic. POPULATION: 26 volunteers (49.8±14.6 years), WHO functional class II-III and a mean pulmonary artery pressure of 45 mmHg. METHODS: Patients underwent three field walk test: 6MWT, incremental shuttle walk test (ISWT), and endurance shuttle walk test (ESWT) and CPET on different, non-consecutive days. The main outcome measures were heart rate and perception of effort at the peak of exercise. RESULTS: The ISWT achieved maximum levels of effort without significant difference in any physiologic response compared to CPET. The physiological responses during ISWT were significantly higher than 6MWT and ESWT responses. CONCLUSIONS: The ISWT produced the greatest physiologic response of the field tests safely for which reason it appears to be the most effective test to assess FC of PH patients. CLINICAL REHABILITATION IMPACT: The self-paced characteristic of the 6MWT and lower physiologic responses compared to the CPET were the main reason for this test to be classified as submaximal in PH patients. The physiological responses during the ESWT were significantly lower than other field tests highlighting the need for more research on this test and other field test in PH patients.