Reference values for the six-minute walk test in obese Indian population

Ravi Dosi, Ashwin Songara, Prakash Joshi, Arpit Jain, Awadesh P.S. Solanki


Background: The six-minute walk test is one of the most powerful test used to measure the functional capacity in various chronic conditions such as in Obesity. There are very few reported studies on SMWT on Obese population all over the world, and there is no reference equation for SMWD. The aim of present study is to propose a Reference equation which could predict the distance walked in SMWT by obese individuals.

Methods: 150 obese individuals free from any cardiorespiratory disease were randomized into 2 groups. SMWT data from group A was used to propose the reference equation and SMWD for Group B was predicted. Significance of difference between predicted and original values for group B was found.

Results: Mean SMWD for Group A was 304.56 (SD= 68.28) which significantly correlated to (by using linear regression method) age (r = -0.32, p <0.001), BMI (r = -0.43, p <0.001) SpO2* (r=-0.35, p<0.001). These could explain 56% of the total variance in 6MWT. Though the difference between predicted and original values for group B wasn’t found to be statistically significant. The proposed Reference equation is:

6MWT distance = (6.8) O2 saturation-(4.3) BMI-(0.6) age-170.64.

Conclusions: SMWT is a simple, safe and powerful test to assess the functional status. The standardized SMWD values for Indian obese population would serve as benchmark to assess baseline functional capacity, prescribe proper and safe exercise intensity and monitor changes after rehabilitation interventions.


Obese, Six-minute walk test, Six-minute walk distance

Full Text:



American Journal of Respiratory and critical care medicine Vol. 166, No. 1 | Jul 01, 2002. Available at


Balke B. A simple field test for the assessment of physical fitness. CARI Report. 1963;63:18.

Solway S, Brooks D, Lacasse Y, Thomas S. A qualitative systematic overview of the measurement properties of functional walk tests used in the cardiorespiratory domain. Chest. 2001;119:256-70.

Guyatt GH, Thompson PJ, Berman LB, Sullivan MJ, Townsend M, Jones NL, et al. How should we measure function in patients with chronic heart and lung disease? J Chronic Dis. 1985;38:517-24.

Capodaglio P, De Souza SA, Parisio C, Precilios H, Vismara L, Cimolin V, et al. Reference values for the 6-Min Walking Test in obese subjects. Disability and rehabilitation. 2013;35(14):1199-203.

Enright PL, Sherrill DL. Reference equations for the Six-Minute Walk in healthy adults. Am J Respir Crit Care Med. 1998;158:1384-7.

Ramanathan RP, Chandrasekaran B. Reference equations for 6-min walk test in healthy Indian subjects (25-80 years). Lung India: official organ of Indian Chest Society. 2014;31(1):35.

Hulens M, Vansant G, Claessens AL, Lysens R, Muls E. Predictors of 6-minute walk test results in lean, obese and morbidly obese women. Scand J Med Sci Sports. 2003;13:98-105.

Troosters T, Gosselink R, Decramer Ml. Six minute walking distance in healthy elderly subjects. Eur Respir J. 1999;14(2):270-4.

Wasserman K, Hansen JE, Sue DY, Casaburi R, Whipp BJ. Principles of exercise testing and interpretation, 3rd Edition. Philadelphia: Lippincott, Williams and Wilkins; 1999.

Weisman IM, Zeballos RJ. An integrated approach to the interpretation of cardiopulmonary exercise testing. Clin Chest Med. 1994;15:421-45.