6 Minute Walk Test

Physicians use the 6 Minute Walk Test (6MWT) to assess functional heart and lung capacity for frail patients aged 60 to 90 years. They also use the test to evaluate measures taken to improve exercise tolerance in healthy older people. Physicians may also use the 6MWT to evaluate patients with a variety of other conditions, such as osteoarthritis, fibromyalgia, heart failure, chronic obstructive pulmonary disease (COPD), and stroke.1,2,3

Clinicians largely use the 6MWT to measure the response of patients with moderate to severe heart or lung disease to medical interventions, such as surgery.4 They may also use it to predict morbidity and mortality and assess functional status.

The test evaluates the general response of the patient’s various bodily systems during this exercise, including the pulmonary and cardiovascular systems, systemic circulation, peripheral circulation, blood, neuromuscular units, and muscle metabolism. While researchers have found some correlation with cardiopulmonary testing, it is considered a complement to more formal testing.2

Patients don’t need exercise equipment or advanced training to complete the 6MWT. They need only to walk on a hard, flat surface for six minutes. The test particularly helps clinicians assess how patients might function during daily activities, which don’t usually call for maximal exercise capacity. Patients walk at their own pace during the test, resting as needed. 

Morbidity & Mortality Associations

The 6 Minute Walk Test may help predict morbidity and mortality for a variety of conditions. Researchers have found a significant difference in mortality rates based on the distance people walk during the 6MWT. A study of 102 healthy participants aged 20 to 50 years, who performed the 6MWT, listed the mean distance walked as 614 meters and the average distance as 593 meters for women and 638 meters for men.5

A study of 43 people with stable New York Heart Association functional II or III heart failure reported a mortality rate of 7% for people who walked more than 300 meters during the 6MWT and 79% for people who walked 300 meters or less, with significantly increased death risk for the second group.6

Adversely, a COPD study of nearly 15,000 patients reported that more than half of patients who walked less than 350 meters died within a 12-month period, while more than half of the patients who walked at least 350 meters survived.2 Additional studies have reported that those with lower 6MWT and left ventricular ejection fraction of up to 0.30 have an increased risk of death.

An increased risk of hospitalization and mortality was found in people with chronic respiratory disease and a low 6MWT.2 For patients with COPD and low 6MWT, an increased risk of death, hospitalization, or COPD exacerbations, were seen.7,8  

6 Minute Walk Test Contraindications

Due to an increased risk for arrhythmias or cardiovascular collapse during the 6MWT, the test is contraindicated in patients with certain cardiovascular conditions. Conditions include patients who have unstable angina and/or myocardial infarction during the month previous to the test, resting heart rates of more than 120, or blood pressure of more than 180/100 mm Hg.

Patients with stable exertional angina may undergo the 6MWT after taking their anti-angina medication, with readily available rescue nitrate medication.9

6MWT Guidelines

The European Respiratory Society (ERS) and American Thoracic Society (ATS) established technical standards for field walking tests in 2014. They recommend that tests are performed along a course of at least 100 feet (roughly 30 meters). Preferably, this course is quiet, located within a physiotherapy gym or dedicated exercise testing room, and set at a comfortable temperature (with air conditioning available if needed).3

Further, patients should have rapid access to emergency medicine, including a crash cart, oxygen, sublingual nitroglycerine to treat chest pain, and Albuterol to relieve symptoms of asthma and COPD during the 6MWT. There should also be a telephone or other means of calling for help in the case of emergencies.3

Patients should wear comfortable clothing and appropriate shoes for walking, use their usual walking aids if any, and take their regular medications before the 6MWT. Those who are on long-term oxygen therapy should receive oxygen at their standard flow rate or as directed by a physician or a protocol.

Patients are not allowed to exercise vigorously within two hours of beginning the test or take a shortened version of the test or warm up before the test. Any respiratory function tests scheduled for the same day as the 6 Minute Walk Test should take place first, and the patient should take at least a 15-minute rest in a chair near the start of the 6MWT before beginning this test.

Finally, any subsequent 6MWT should occur close to the same time of day to minimize variations that may happen throughout the day. Patients should undergo at least two of these tests to help show if there are any changes over time.3

While the ERS/ATS guidelines assume the 6MWT will be done under medical supervision, a 2021 study of 110 patients scheduled for heart or vascular surgery reported that tests performed with smartphones or smart watches were as reliable as in-clinic tests. The investigators noted that digital tests allow physicians to continuously and objectively assess how patients function in the real world, evaluate capacity before performing any operations, and see how patients respond to therapy. Digital tests may also help provide more meaningful telemedicine encounters.10

References

1. Troosters T, Gosselink R, Decramer M. Six minute walking distance in healthy elderly subjects. Eur Respir J. 1999;14(2):270-4. doi:10.1034/j.1399-3003.1999.14b06.x

2. Harada ND, Chiu V, Stewart AL. Mobility-related function in older adults: assessment with a 6-minute walk test. Arch Phys Med Rehabil. 1999; 80(7):837-41. doi:10.1016/s0003-9993(99)90236-8

3. Fulk G, Echternach J, Nof L, O’Sullivan S. Clinometric properties of the six-minute walk test in individuals undergoing rehabilitation post stroke. Physiother Theory Pract. 2008;24(3):195-204. doi:10.1080/09593980701588284

4. O’Keeffe ST, Lye M, Donnellan C, Carmichael DN. Reproducibility and responsiveness of quality of life assessment and six minute walk test in elderly heart failure patients. Heart. 1998;80(4):377-82. doi:10.1136/hrt.80.4.377

5. Chetta A, Zanini A, Pisi G, et al. Reference values for the 6-min walk test in healthy subjects 20-50 years old. Respir Med. 2006;100(9):1573-8. doi:10.1016/j.rmed.2006.01.001

6. King SJ, Wessel J, Bhambhani Y, Sholter D, Maksymowych W. The effects of exercise and education, individually or combined, in women with fibromyalgia. J Rheumatol. 2002;29(12):2620-7. 

7. Focht BC, Rejeski WJ, Ambrosius WT, Katula JA, Messier SP. Exercise, self-efficacy, and mobility performance in overweight and obese older adults with knee osteoarthritis. Arthritis Rheum. 2005;53(5):659-65. doi:10.1002/art.21466

8. ATS Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories. ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med. 2002;166(1):111-7. doi:10.1164/ajrccm.166.1.at1102. Erratum in: Am J Respir Crit Care Med. 2016;193(10):1185. doi:10.1164/rccm.19310erratum

9. Hajiro T, Nishimura K, Tsukino M, Ikeda A, Koyama H, Izumi T. Analysis of clinical methods used to evaluate dyspnea in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 1998;158(4):1185-9. doi:10.1164/ajrccm.158.4.9802091

10. Mak J, Rens N, Savage D, et al. Reliability and repeatability of a smartphone-based 6-min walk test as a patient-centred outcome measure. Eur Heart J. 2021;2(1):77-87. doi:10.1093/ehjdh/ztab018