The six-minute walk test is performed to measure the total distance walked by a patient in six minutes. It is used in patients with moderate to severe heart or lung diseases that limit their everyday activities and prevent them from performing other more demanding cardiopulmonary exercise tests. The six-minute walk distance assesses the submaximal level of functional capacity that reflects the functional exercise level for everyday activities. This test is most frequently used before and after therapeutic interventions in order to assess the effect of treatment. The six-minute walk test is safe and simple. It does not require expensive equipment and, if performed in line with the guidelines, it has an excellent reproducibility.