The six-minute walk test is applied internationally as a comprehensive assessment of the functional status of the whole body in moderate to severe disease, focusing on exercise capacity, including cardiopulmonary function, skeletal muscle function, and nutritional level. The six-minute walk test is highly correlated with exercise oxygen consumption. The six-minute walk test is an exercise test that is simple to perform: a straight-line distance of up to 30.5 meters (100 feet) is marked on a flat surface with a chair at each end. The patient walks back and forth between them at a pace determined by the patient’s physical ability. The patient is monitored every 2 minutes and any shortness of breath, chest pain, or other discomfort is recorded. If the patient has difficulty with physical strength, he or she may rest temporarily or discontinue the test. At the end of the trial after 6 minutes, the monitor counts the distance walked by the patient to assess the results. Early experts in the United States who conducted this test classified the distance patients walked into four levels: Level 1 was less than 300 meters, Level 2 was 300 to 374.9 meters, Level 3 was 375 to 449.5 meters, and Level 4 was more than 450 meters. The lower the level, the worse the cardiopulmonary function. Those who reach level 3 and level 4 can be said to be close to or have reached normal cardiopulmonary function.