2.3.2. Cardiopulmonary Function
A 40-m track with a firm, level, and straight surface was used for the 6-min walk test. Within the specified 6-min period, each patient was permitted to pause and take a break as needed. The walking distance was calculated after the completion of the task. A portable monitor was used to continually record the patient’s HR during the 6-min walk test. Following this test, patients reported their felt degree of exertion on a number scale ranging from 6 (no exertion) to 20 (maximal exertion) [