THE SIX-MINUTE WALK TEST
How Medical Personnel should administer the 6MWT, Paul L Enright MD: The 6MWT is safer, easier to administer, better tolerated, and better reflects activities of daily living than other walk tests (such as the shuttle walk test). The primary measurement is 6-min walk distance (6MWD), but during the 6MWT data can also be collected about the patient’s blood oxygen saturation and perception of dyspnea during exertion. When conducting the 6MWT do not walk with the patient and do not assist the patient in carrying or pulling his or her supplemental oxygen. The patient should walk alone, not with other patients. Do not use a treadmill on which the patient adjusts the speed and/or the slope. Do not use an oval or circular track. Use standardized phrases while speaking to the patient, because your encouragement and enthusiasm can make a difference of up to 30% in the 6MWD.
Walking tests have been around since the 1960s, when the 12-min walk was popularized by an aerobics fitness enthusiast as a quick and easy fitness test. There’s a full range of tests that you could perform to assess a patient’s functional capacity. The easiest is just a questionnaire or self-report of how much work the patient can do. You might ask, "How many flights of stairs can you climb or how many blocks can you walk?" But patients differ in their ability to recall that kind of information and may overestimate or underestimate their true functional capacity, so objective measurements are usually better than self-reports. Another easy test of fitness is the number of stairs the patient can climb. Many surgeons have said that if the patient can walk up 2–3 flights of stairs, then he or she can survive surgery.
6-Minute Walk Test Versus Shuttle Walk Test: How does the 6MWT compare to the shuttle walk test, which is frequently used in Great Britain? With the 6MWT the instructions to the patient are to "walk as far as you can during 6-minutes," whereas the shuttle walk test pressures the patient to meet multiple deadlines, according to beeps from an audio cassette tape. The 6MWT is self-paced, and a patient is probably less likely to push himself beyond his endurance or through angina or other pain than during the shuttle walk test. The shuttle walk test is better correlated with peak oxygen uptake, as measured by a full cardiopulmonary exercise test, but not as many people are using the shuttle walk test.
What variables can be measured in the 6MWT? The primary measurement is the total distance walked. Secondary measures can include fatigue and dyspnea, measured with a modified Borg or visual analog scale. Arterial oxygen saturation can also be measured via pulse oximetry, as long as the oximeter is portable and not heavy.
Conducting the Test...ask the patient to wear comfortable footwear. During the test do not walk with the patient, because even if you walk behind them, it will alter their pace. If the patient is using supplemental oxygen during the walk, don’t help push the oxygen tank or the 6MWD will not be the same as if the patient was pushing the tank, as he or she would do at home. In one study the investigators walked 6 people at the same time, which created competition among the study participants, resulting in a 30% larger mean 6MWD than tests in which the patients walked alone.