What are the guidelines for interpreting and reporting the six-minute walk test according to the American Thoracic Society (ATS)/European Respiratory Society (ERS)?

Guidelines for Six-Minute Walk Test Interpretation and Reporting According to ATS/ERS

The American Thoracic Society (ATS) recommends a standardized protocol for the six-minute walk test (6MWT) that includes specific requirements for test environment, equipment, patient preparation, measurement procedures, and interpretation to ensure reliable and reproducible results for assessing functional exercise capacity in patients with chronic diseases. 1, 2

Test Environment and Setup

• The 6MWT should be performed in a 30-meter long, flat, straight, enclosed corridor with minimal traffic and a hard surface 1
• The corridor should be marked every 3 meters, with turnaround points marked by cones and a starting line marked with brightly colored tape 1
• Treadmills should not be used as they reduce walking distance by approximately 14% compared to corridor tests and prevent patients from properly pacing themselves 1, 3
• Avoid using oval or circular tracks as patients walk farther on continuous tracks (mean 92 ft farther) than on straight courses 1, 3

Required Equipment

• Countdown timer or stopwatch 1
• Mechanical lap counter 1
• Two small cones to mark turnaround points 1
• A chair that can be easily moved along the walking course 1
• Worksheets on a clipboard 1
• Emergency supplies: oxygen source, sphygmomanometer, telephone, and automated electronic defibrillator 1, 2
• Borg scale printed on heavy paper (11 inches high, laminated) in 20-point type size 1

Safety Considerations

• Testing must be conducted where rapid emergency response is possible 1
• The technician must be certified in cardiopulmonary resuscitation (minimum Basic Life Support) 1
• Reasons to immediately stop the test: chest pain, intolerable dyspnea, leg cramps, staggering, diaphoresis, and pale or ashen appearance 1
• Absolute contraindications include unstable angina or myocardial infarction during the previous month 2
• Relative contraindications include resting heart rate >120 bpm, systolic blood pressure >180 mmHg, or diastolic blood pressure >100 mmHg 2

Patient Preparation

• Patients should wear comfortable clothing and appropriate walking shoes 1
• Patients should use their usual walking aids (cane, walker) during the test 1
• Continue the patient's usual medical regimen 1
• A light meal is acceptable before morning or early afternoon tests 1
• Patients should avoid vigorous exercise within 2 hours of the test 1
• For patients on chronic oxygen therapy, deliver oxygen at their standard rate or as directed by a physician 1

Test Procedure

1. Patient should sit at rest for at least 10 minutes before starting 1
2. Measure baseline vital signs: heart rate, blood pressure, oxygen saturation, and Borg dyspnea scale 1, 2
3. Provide standardized instructions to the patient: "The object of this test is to walk as far as possible for 6 minutes..." 1
4. Use standardized encouragement phrases at specific times:
   • After first minute: "You are doing well. You have 5 minutes to go." 1
   • At 4 minutes remaining: "Keep up the good work. You have 4 minutes to go." 1
   • At 3 minutes remaining: "You are doing well. You are halfway done." 1
   • At 2 minutes remaining: "Keep up the good work. You have only 2 minutes left." 1
   • At 1 minute remaining: "You are doing well. You have only 1 minute to go." 1
   • At 15 seconds remaining: "In a moment I'm going to tell you to stop..." 1
5. Do not walk with the patient or provide additional encouragement beyond the standardized phrases 1, 3
6. Count laps using the lap counter and mark the final partial lap distance 1

Post-Test Assessment and Reporting

• Record the total distance walked in meters (rounding to the nearest meter) 1
• Measure post-walk heart rate, blood pressure, oxygen saturation, and Borg dyspnea scale 1, 2
• Ask the patient what, if anything, prevented them from walking farther 1
• Document any symptoms that caused the test to be stopped prematurely 1
• For continuous pulse oximetry, record the lowest SpO2 as it's an important marker of disease severity and prognosis 4

Interpretation Guidelines

• A practice test should be considered, especially in research settings 1
• If a practice test is performed, wait at least 1 hour before the second test and report the highest 6MWD as baseline 1
• In adults with chronic respiratory disease, a change in 6-minute walk distance of 30 meters or more indicates a clinically significant change 4
• The absolute 6MWD and change in 6MWD are predictive of morbidity and mortality in patients with COPD, pulmonary arterial hypertension, idiopathic pulmonary fibrosis, and lung transplant candidates 5

Common Pitfalls to Avoid

• Inconsistent encouragement between tests can significantly affect results (up to 30% difference in distance) 3
• Failure to account for practice effects (performing only one test when measuring change over time) 4
• Inadequate documentation of oxygen supplementation or medication use 2
• Variations in walkway length (using shorter corridors requires more time to reverse directions, reducing walking distance) 1, 6
• Technician variability in test administration and encouragement 2