Two excellent indicators of exercise capacity are the six-minute walk test (6MWT) and the Incremental Shuttle Walk Test (ISWT). These two tests can reveal information about an individual’s lung function, as the pulmonary system is used during physical activity. The 6MWT is often used as an outcome to test the efficacy of drugs in clinical trials for pulmonary hypertension, but there are other potential uses for these tests. A group of researchers recently found that these tests are reliable in adults with non-cystic fibrosis bronchiectasis.
During the 6MWT, an individual simply walks on a flat, hard surface for six minutes. The goal is to walk as quickly as possible to cover the most distance. To complete this goal, an individual’s pulmonary and cardiovascular systems are put to the test, but the individual remains at a submaximal level of exertion. This better reflects the individual’s functional exercise capacity during daily physical activities.
Alternatively, the ISWT uses two cones separated by a distance of nine meters (with the distance around the cones a total of ten meters) and a CD with auditory beeps. The goal for this test is to complete the greatest number of laps that can be completed around the two cones. A lap is defined by two beeps, whereby the first beep signals the start of walking, and the second beep signals the time at which the individual should have arrived at the second cone. Throughout the course of the test, the time between beeps is reduced.
In the study, “Field Walking Tests Are Reliable and Responsive to Exercise Training in People With Non-Cystic Fibrosis Bronchiectasis,” which was published in Journal of Cardiopulmonary Rehabilitation and Prevention, researchers were testing the hypothesis that both the 6MWT and ISWT can be used as reliable indicators of exercise capacity in non-cystic fibrosis bronchiectasis patients. Additionally, they believed the tests could be responsive to positive changes in exercise capacity following a patient’s use of exercise training.
Eighty-five participants were recruited for the study. Each completed two rounds of the 6MWT and two rounds of the ISWT at the beginning of the study, then again after eight weeks of exercise training. At the closing of the study, the researchers analyzed increases in the distances walked during both tests. They first noted that the use of two rounds was necessary to overcome the learning curve of completing the tests. They second noted that both tests revealed positive changes following exercise intervention. Patients were 3% better at the 6MWT and 4% better at the ISWT at the end of eight weeks.
If clinicians wish to use the 6MWT or the ISWT to help determine exercise capacity in their patients with non-cystic fibrosis bronchiectasis, they should allow their patients to complete the exercises twice each to account for learning effects. If this is allowed, then both tests may be reliable indicators of if a patient is improving following interventional treatments.