The 6-Minute Walk Test

You have probably heard of 6-minute walk test (6MWT) in your travels as a respiratory therapy student, and thought: “I wish a benevolent, handsome instructor would write a paper about that.”  Well today is your lucky day!  Well, at least as far as the benevolent part. 

The most basic explanation of what a 6MWT is:  it is a test to see how far a person can walk in, you guessed it, 6 minutes.  At its core, it really is that simple, and is not a procedure that requires a lot of fancy equipment, high tech gadgets, or money. 

A properly trained healthcare professional, with a minimal amount of basic gear, can put a patient through a 6MWT and gain a lot of clinically useful information about their exercise capacity that can play an important role in the care of that patient.

A Little More Background….

For decades, patients with cardiopulmonary disorders like COPD and CHF were sort of told that the best medicine for their condition was simply to rest.  If you feel short of breath just sitting there, why would you want to exert yourself and make it worse?  It was felt that those patients were just “too sick” to exercise, or in some cases, even to do activities of daily living.  Maybe they were given supplemental oxygen for their shortness of breath, maybe some drugs for their heart and blood pressure, but for the most part, they were told “Good luck with that” as they suffered ever decreasing quality of life. 

It was a miserable existence.  There was a radical change in thought in the late 1950’s and early 60’s; physicians started to buy into the idea of exercise and cardiac and pulmonary rehabilitation, and that while patients may be suffering from progressive diseases, tailored exercise programs could actually improve quality of life and more optimally use the lung and heart function that was still there. 

As is the case when things like this evolve, there was little consensus on techniques and protocols, and there were growing pains as practitioners struggled to make sense of the data that was being collected in the research in this growing field. 

Many different testing techniques and procedures were used by providers from many fields in healthcare, and there became a need for a standardized approach.  To that end, the American Thoracic Society developed a first set of standard guidelines for the 6MWT and released them in 2002. 

A 6MWT is considered a submaximal test, that is, it does not push a patient to their physical limits, although they will definitely be a little worn out by the end.  There are other professional groups that have released similar guidelines for a variety of exercise testing, but this paper will focus on the ATS guidelines specifically.

Why is the 6MWT important to us as respiratory therapists?

The 6MWT does give us a pretty simple and practical way to gather information on a patient’s functional status and capacity for exercise, and it is pretty well tolerated buy patient’s with moderate to severe cardiopulmonary disease and other disorders. 

It puts the patient in charge- they dictate the pace and what they can do.  It not only gives us information about the heart and lung function, but the circulatory, muscular, and neurological systems as well. 

It also gives us an objective, reproducible way to assess and investigate progression of disease, success of therapeutic treatments and drugs, and in some case, can act as a marker or predictor of successful surgical outcomes or even mortality. 

It is a very common test done in both cardiac and pulmonary rehabilitation units, physical therapy and exercise science departments, outpatient pulmonary clinics, and is becoming increasingly used in discharge planning to get the patient hooked up with the right resources.

Do I need to know this for the NBRC RRT board exams?

Let’s be honest here for a minute.  As a respiratory care student or a recent graduate preparing for the big bad NBRC credentialing exams, what you really care about, is the answer to that age old question: “Do we need to know this for the test”?  And that answer is a resounding “Yes.  Yes, you do.” 

You will find questions concerning the 6MWT on both the TMC and CSE exams.  Just use some common sense here, and know the situation presented in a question.  If your patient is in the ER suffering from an asthma attack, or in the throes of a COPD exacerbation, that would not be the time to consider doing a 6MWT.  Likewise, your intubated, septic, critically ill patient in the ICU would not be a candidate for a 6MWT. 

But how about that stable patient with known COPD who is getting ready to be discharged home?  Could a 6MWT help get a baseline idea of what their functional status is, and maybe even get them to buy into the idea of pulmonary rehab or an outpatient exercise program?  Absolutely!  Or how about if they actually get themselves into an outpatient pulmonary rehabilitation program or clinic; couldn’t serial 6MWT’s serve as a motivation to them to continue working hard? 

They will see objective proof that the exercises are working when they see actual improvement in the distance they walked; the numbers do not lie. 

Like with most patient scenarios presented on both the TMC and CSE  you need to ask yourself a couple of basic questions when it comes to the 6MWT: 

1. Is the test safe to perform at this time? 
2. What information do I hope to gain from this test- is it valuable to this case? 

If you can answer “yes” to those, then you should strongly consider the 6MWT as one of your choices.

What are the limitations of the 6MWT?

Just like anything in life, there are limitations to a 6MWT. Obviously, you are not going to do this on a critically ill, unstable patient in the ICU.  It is a pretty simple test, so sometimes it is difficult to know what to do with the results; there is still a lot of grey area, and it is not a substitute for more detailed exercise testing procedures. 

If a patient has vital signs or values outside of the standard limits suggested, the physician may need to decide if the test is really worth attempting, or maybe it can be modified. 

The testing area itself must have the appropriate equipment and trained personnel (ACLS preferred) present in case things do go south with a patient; the test may need to be postponed if these simple safety concerns are not met.  If a patient is having chest pain, crazy dyspnea, or just plain looks bad, the test should be stopped immediately before things spiral out of control.