Six-Minute Walk Test (6MWT)

What it measures

The six-minute walk test (6MWT) is a submaximal field test of functional exercise capacity. The distance walked (6MWD) reflects the integrated response of the heart, lungs, circulation and muscles to everyday exertion.^1,2

When we use it

In COPD, interstitial lung disease, pulmonary hypertension and heart failure; before and after pulmonary or cardiac rehabilitation; and in pre-operative and transplant assessment.³

How it is done

The patient walks back and forth along a flat, 30-metre corridor for six minutes, covering as much ground as possible, with standardised phrases of encouragement only.⁴ Heart rate, SpO₂ and Borg breathlessness/fatigue scores are recorded before and after; rests are allowed and the clock keeps running. Because there is a learning effect, two tests are recommended and the best distance reported.

Interpretation

• Distance is compared with reference equations for age, sex, height and weight.
• A fall in SpO₂ of ≥4%, or below 88%, is a clinically important exertional desaturation.
• The minimal important difference is around 30 m (roughly 25–33 m).
• A short distance (for example under ~350 m in COPD or heart failure) carries prognostic significance.

Use in cardiorespiratory physiotherapy

• Sets and evaluates an exercise prescription.
• Flags exertional desaturation that warrants an ambulatory oxygen assessment.
• Serves as a primary outcome measure for pulmonary and cardiac rehabilitation.

Cautions & stopping criteria

Absolute contraindications include unstable angina or a myocardial infarction in the previous month; relative cautions include a resting heart rate over 120 or blood pressure over 180/100 mmHg. Sources differ on that blood-pressure figure: the ATS six-minute-walk statement gives 180/100 mmHg as a relative caution for testing, while exercise-in-hypertension guidance defers training at around 180/110 mmHg or higher — see the hypertension evidence page. Neither figure overrides the other; the decision to walk a patient today is a clinical one. Stop the test for chest pain, intolerable breathlessness, leg cramps, staggering, sweating with pallor, or a critical fall in SpO₂. Keep the corridor, encouragement and tester consistent so repeat tests are comparable.

Prescribing exercise from the result

Convert the distance to an average speed — 6MWD ÷ 360 — then prescribe endurance walking at 70–80% of that speed for 20–30 minutes, using intervals at the same speed where the duration cannot yet be sustained. A 400 m 6MWD gives 1.11 m/s, so training is roughly 0.78–0.89 m/s (2.8–3.2 km/h). Where the test showed exertional desaturation, expect it in training and plan intervals or oxygen assessment rather than accepting it. Full method, including progression rules and what to do when heart-rate targets are invalid, is in prescribing exercise from test results.

References & evidence base

1. Holland AE, Spruit MA, Troosters T, et al. An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease. Eur Respir J 2014;44(6):1428–1446.
2. Enright PL, Sherrill DL. Reference equations for the six-minute walk in healthy adults. Am J Respir Crit Care Med 1998;158(5):1384–1387.
3. Singh SJ, Puhan MA, Andrianopoulos V, et al. An official systematic review of the European Respiratory Society/American Thoracic Society: measurement properties of field walking tests in chronic respiratory disease. Eur Respir J 2014;44(6):1447–1478.
4. 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):111–117.

References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use.