This blog provides detailed information on a simple but increasingly important test in medical diagnostics: the 6-minute walk test. It discusses when and why we perform it, its contraindications, how it is conducted, the factors affecting its variability, and its clinical implications. You can also watch the content as a video lecture.
In this blog you will learn:
The 6-minute walk test measures the distance that a patient can quickly walk in 6 minutes on a flat surface.
The standardisation by the American Thoracic Society (ATS) made the 6MWT a standardised time test for assessing a patient’s functional capacity. It assesses various organ systems involved in walking and exercise, including the cardiac and pulmonary systems, peripheral and systemic circulation, neuromuscular units, and muscle metabolism.
Here is a video lecture on the various aspects of the 6-minute walk test, its performance and interpretation, delivered by Dr. Anže Žgank:
Aerobic capacity and endurance are useful indicators, e.g. for monitoring progress or determining the general level of preparedness of elite athletes. However, they are also holistic diagnostic indicators of the state of cardiopulmonary and musculoskeletal systems involved in physical exercise, which also makes this kind of testing very useful in diagnosing and monitoring a number of diseases.
In difference to stress ECG, which offers diagnostic information at maximal exercise capacity, the 6MWT assesses functional capacity at submaximal level, at everyday physical activity levels . This means that it can also be used for patients who are not capable of performing other functional capacity tests, e.g. the cardiolpulmonary exercise test (the 6MWT actually correlates well with the VO2 max, measured with this particular test). It is thus a useful evaluation method for a wide variety of conditions. 
The indications can be divided into three groups: 
Clinicians also use the 6MWT for a wide variety of non-cardiopulmonary diseases, including neuromuscular conditions such as Charcot-Marie-Tooth disease (i.e. inherited neurological disorders that mainly affect the peripheral nerves) and myasthenia gravis (i.e. chronic autoimmune neuromuscular disorder that primarily affects the muscles responsible for voluntary movements) [3, 4].
The 6MWT has absolute and relative contraindications:
Among others, absolute contraindications include:
Among others, relative contraindications include:
The 6MWT is best conducted indoors; performing it outdoors may affect the test result. We need a flat and enclosed corridor with a durable surface, at least 30 m long. It is important to choose a location that is not very busy (as other people can inadvertently interfere or distract the patient), but where a fast emergency response can be initiated. 
The walking course should measure 30 m in length. Going up and down the corridor once is regarded as one lap (60 m). The corridor should have clear markings every 3 m. At both ends of the course, there should be designated turnaround points, typically indicated by the placement of cones, such as bright orange traffic cones. Additionally, the starting line, which signifies the beginning and end of each lap, should be clearly demarcated on the floor using brightly-coloured tape.  
The examiner needs: 
Patients should be dressed comfortably in appropriate clothing and wear suitable walking shoes. They should also be asked to utilise any regular walking aids; please document them on the assessment form.  
Prior to initiating the 6MWT, patients should rest for a minimum of 10-15 minutes.
Patients on long-term oxygen therapy should continue with their usual oxygen flow rate, following the direction of their physician or a predefined protocol.
Patients should also be reminded to adhere to their regular medication regimen. Please note the medication type, dosage, and the time elapsed since the last dose before the test.
The patient does not need a warm-up before the test.
Any future test repetitions should be performed at the same time of day.
The test is performed in 10 steps.
Several factors can influence the variability of 6MWT results. These include: 
The result can be given as the absolute distance covered during the test, or the difference between the distances of two consecutive tests can be noted.
Please note that the 6-minute walk distance (6MWD) alone is not a specific diagnostic measurement. The following factors should be considered for clinical significance of the result.
While the 6MWT provides valuable information, the test alone cannot diagnose specific conditions. Many underlying diseases can affect the distance. The clinical significance of the result depends on the patient’s condition, which may have already been diagnosed or is still unknown. Therefore, it’s crucial to interpret the results alongside those of other diagnostic procedures.
Maintaining stable SpO2 levels is important during the 6MWT. A drop in SpO2 by more than 5% may indicate an underlying respiratory or cardiac disorder.
The 6MWT is not only diagnostic but also holds significant prognostic value. Studies have shown its relationship with morbidity and mortality in various patient populations: 
A Canadian study on COPD patients found a survival correlation between COPD and 6MWD: the patients who could walk over 250 m had a mean survival of about 42 months, while those who walked less than 150 m had a mean survival of 28 months. 
Another study on patients with this disease showed that walking less than 300 m was associated with a 2.4 times higher mortality risk. Similarly, an SpO2 fall of more than 10% increased the mortality risk by 2.9 times. 
A systematic review of studies on patients with a pathology found that fall in the 6MWT distance by 14 to 30 m was considered clinically important deterioration. 
The 6MWT has proven its utility during the COVID-19 pandemic. A Danish study highlighted its importance in diagnosing exercise-induced hypoxia in patients just before hospital discharge. This diagnosis holds several key advantages: 
An Italian study demonstrated the 6MWT’s usefulness in monitoring rehabilitation progress in patients who have undergone intensive care unit (ICU) treatment. This application of the test plays a vital role in ensuring the well-being and progress of patients after their critical care journey. 
In an Indian study, patients with pulmonary diseases performed the 6MWT with and without face masks. The results revealed that wearing a mask during the test led to shorter walking distances. This factor has become particularly relevant during the COVID-19 pandemic, underscoring the importance of considering external variables when assessing 6MWT results. 
Given the significant impact of heart failure on functional exercise capacity, particularly in individuals with class C and D disease, the 6-Minute Walk Test (6MWT) emerges as an exceptionally suitable assessment method. It offers affordability, demands no specialised equipment, maintains non-invasiveness, and is generally well-tolerated by most patients, except for those with strong mobility limitations.
A decline in 6MWT performance among heart failure patients correlates with heightened risks of mortality, non-fatal cardiovascular events and hospitalisations, particularly within the B and C subclasses of heart failure.
To read an extensive article on the risk factors and prevalence of heart failure, its morbidity, mortality, economic impact and the use of the 6MWT in patients with this condition, click here.
The 6MWT serves as a valuable prognostic indicator for long-term PH-related mortality and the risk of hospitalization. In fact, it has been discovered that patients capable of walking at least 400 m within the allocated 6-minute timeframe generally exhibited the most favorable prognosis. The 6MWT is also used for following the progression of the disease and assessing functional capacity.
To find out more about pulmonary hypertension, its burden and morbidity, and the way the 6MWT is used in assessing patients with this disease, click here.
In the context of pulmonary conditions, healthcare professionals commonly recommend the 6-Minute Walk Test (6MWT) for specific patient groups. This includes individuals awaiting lung transplantation and those diagnosed with cystic fibrosis. The 6MWT also proves valuable in assessing post-surgical mortality among patients who have undergone lung resection and in determining the severity of pulmonary arterial hypertension, a complex cardiopulmonary condition that presents significant treatment challenges.
To find out more about the use of the 6MWT in pulmonary issues and specifically how it is used in patients with COPD and COVID 19, click here.
Assessing the exercise capacity of seniors, a diverse demographic united only by their age, serves the crucial purpose of identifying those who require tailored exercise instructions and recognising individuals who may be unable to engage in physical activity promptly. This underscores the vital utility of the 6MWT, which provides a comprehensive evaluation of cardiopulmonary and muscular fitness.
To find out about the average walking distances of healthy seniors and the effect of various conditions on their results, click here.
Dr. Anže Žgank, pulmonology resident at University Medical Centre Ljubljana, Slovenia
Dr. Anže Žgank graduated from the Faculty of Medicine at the University of Ljubljana (Slovenia) in 2018. He then began his internship at General Hospital Celje, where he also started his residency in internal medicine in 2019. Since 2020, he has been employed as a resident in pulmonology at the Clinical Department of Lung Diseases and Allergy at the University Medical Centre Ljubljana.