Exercise Testing

At our clinic we do the 6mwt during the initial intake for the outcome measure and AACVPR certification. I've noticed that some CR programs, respiratory therapists, and physical therapists note a 6mwt norm. For example, a patient would walk 400m and in the note a norm of 450m would be noted based off gender and age. Does anyone else look at 6mwt norms? If so, is there a citation or formula that is used?

Hi Kirill, at Duke University Hospital we report 6mwt using a % of predicted formula.

Predicted distance for men: 1,140 m - (5.61 X BMI) - (6.94 x age)-153

Predicted distance for women: 1,017 m - (6.24 X BMI) - (5.83 x age)-139

And then we divide actual walked distance/predicted walk distance.

For example: A 58 year old female who is 61 inches and 160 lbs walked 1550 ft (472.44 m) with a predicted walk distance of 489.8195 m. Her % of predicted was 96%

Hope this helps!

Kirill,

The equations provided by Jaqueline are from Enright and Sherrill, 1998. The most recent ERS/ATS statement on walk tests has an accompanying review that includes several 6MWT equations (See citation below). Also, you might consider the recently published non-linear equation from DE Soomer et al. 2025, which includes a greater age range. Hope this helps.

-Brian

Enright PL, Sherrill DL. Reference equations for the six-minute walk in healthy adults. Am J Respir Crit Care Med 1998;158:1384–1387.

Singh SJ, 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 Dec;44(6):1447-78. PMID: 25359356.

De Soomer K, et al. New reference values for the 6-minute walk distance in a European population across the full adult age range. Respir Med. 2025 Aug-Sep;245:108205. doi: 10.1016/j.rmed.2025.108205. Epub 2025 Jun 14. PMID: 40523417.

Thank you, Brian and Jacqueline, for your insights. They were very helpful. Brian - I reviewed the De Sommer study and found it very insightful. So I decided to compare the two formulas. The equation from the De Soomer study is:

6MWD = 52.6+(44.3*sex)+(5.42*age)-(0.0739*age^2)+(3.891*height(cm)-(2.015*weight(kg). With sex = 0 for females and 1 for males.

Using your example Jacqueline the predicted 6MWD for a 59 year old female who is 61in and 160lbs, with the De Soomer formula would be 1887ft/575m. Which seems significantly different compared to the Enright equation. In the Singh et al., review it found the Enright equation to have the lowest r value of recent 6MWD reference equations since 2014. They also noted that it's best to use a 6MWT equation that's specific to your region and there appears to be many options.

The De Soomer study also only did only bout of the 6MWT compared to the best practice of two bouts due to the learning effect. They stated most CR programs only do one bout due to time as their reasoning.

I'm in the upper midwest and after quick scan of recent reference equations a study by Delbressine et al. used canadian adults >40years so I will play around using that equation and compare it to the De Soomer equation.

Delbressine JM, Jensen D, Vaes AW, Li PZ, Bourbeau J, Tan WC, Hajian B, van 't Hul AJ, Spruit MA; CanCOLD Collaborative Research Group and the Canadian Respiratory Research Network. Reference values for six-minute walk distance and six-minute walk work in Caucasian adults. Pulmonology. 2023 Sep-Oct;29(5):399-409. doi: 10.1016/j.pulmoe.2023.02.014. Epub 2023 Apr 10. PMID: 37045743.