Attributing patient symptoms of fatigue and dyspnea to heart failure in the presence of, for example, musculoskeletal disorders, pulmonary disorders, or chronic diseases, or even the level of physical conditioning or volition of a patient, is not always readily resolved by history, physical examination, and initial laboratory tests. Cardiology clinical guidelines state, in part, “… Symptoms of both systolic and diastolic heart failure may first manifest as dyspnea or fatigue during physical activity. Therefore, it is appropriate to assess the functional capacity of patients with confirmed or suspected heart failure to determine whether, in fact, such impairment exists…” (6). For this purpose, the 6MW test is practical and simple. In select patients, the value of the test may be increased by the use of rhythm and oximetry monitoring. The conduct of the test should follow published guidelines (5). Although the test is very safe for patients, both resuscitative equipment and qualified personnel must be on-hand and organized so as to manage a rare untoward event (8).