One of the ways that doctors measure the severity of pulmonary fibrosis is by conducting a six-minute walk test (SMWT or 6MWT). We’ll explain what a six-minute walk test is, how it’s performed, and what it can tell you and your doctor about your pulmonary fibrosis.
What is a six-minute walk test?
A six-minute walk test is a simple and reliable way to measure exercise capacity in people with pulmonary fibrosis. You’ll be asked to walk as far as you can in six minutes. As part of the test, the healthcare professional will measure your heart rate, blood pressure, and oxygen saturation. The six-minute walk test is often used to determine whether a patient should use supplemental oxygen. You will sometimes hear that the doctor will prescribe oxygen if your saturation falls below 88% during the test.
The six-minute walk test is just one of the tests that can be done in the doctor’s office. This test measures your capacity for activity, but it does not provide a direct measure of lung function. So, your doctor may also ask you to perform other pulmonary function tests or arterial blood gas tests.
How is a six-minute walk test performed?
The test is usually conducted in a long hallway or along a straight path. Your healthcare provider will ask you to walk as far as possible in six minutes at a comfortable pace. The test is usually performed indoors and the distance is sometimes marked with tape on the floor.
The test can be performed with or without the use of supplemental oxygen. You may be asked to use supplemental oxygen during the test, if you normally use it when walking.
Before the test begins, your healthcare provider will measure your heart rate, blood pressure, and oxygen saturation level. Once you’re ready to start, you’ll begin walking at a comfortable pace. Your healthcare provider will time you and record the distance you cover. They may encourage you to keep walking as long as possible, but they won’t push you beyond your physical limits.
How fast should you walk during the test?
Your tester may tell you to walk at a comfortable pace or may only tell you to walk normally. You might think that you want to walk slowly so that you can “pass” the test. Surely, “passing” the test and not having to use supplemental oxygen is a good thing, right? But, it’s important to note that the six-minute walk test is a test of your ability to function when you are active. It is a measure of physical fitness, particularly in individuals with pulmonary fibrosis. The speed at which you walk during the test should be comfortable and sustainable. But, you will want to walk as you normally would when walking around your house or outdoors so that you get an accurate measurement for your normal level of activity.
What can a six-minute walk test tell you about your pulmonary fibrosis?
A six-minute walk test can provide you and your doctors with important and practical information about your pulmonary fibrosis. Here are a few things that the test can tell you:
- Your ability to function during activity. The results of the test give an idea of your overall ability to perform daily activities or exercise. In pulmonary fibrosis, the scarring of the lung tissue makes it difficult for oxygen to move from your lungs to the bloodstream. If you’re able to walk a greater distance without becoming short of breath or falling below normal oxygen saturation, it’s a sign that your lung function may be better than if you’re only able to walk a shorter distance.
- Your need for supplemental oxygen. The person giving you the test will measure your oxygen saturation level before, during, and after the test. If your oxygen levels drop significantly during the test, it could signal that your lungs are not delivering enough oxygen to your heart and other organs while you are active. This is a factor in deciding whether you need to use supplemental oxygen. Your doctor may prescribe supplemental oxygen for use during activities of daily living or on exertion, such as when exercising, walking or climbing stairs.
- Your response to treatment or disease progression. If you’ve been undergoing treatment for pulmonary fibrosis, the test can be repeated periodically to see changes in lung function and exercise capacity. Your doctor can assess whether your results on the six-minute walk test are staying stable or getting better or worse.
A six-minute walk test is a valuable tool for assessing functional capacity, evaluating changes in ability and identifying the need for supplemental oxygen in people with pulmonary fibrosis. It is a simple test that can help your doctors make more informed decisions about the management of your lung disease. It is common for your doctor to repeat this test periodically, along with other lung function tests.
View the American Thoracic Society’s guidelines for the administration of a six-minute walk test.
Learn about other pulmonary function tests and their meausures.