Reference equation for the 6-minute walk test in healthy North Indian adult males

Lala Ram Swarup Institute of Tuberculosis and Respiratory Diseases, New Delhi, India.

The 6-min walk distance (6MWD) correlates well with functional capacity. However, previous reference equations for the 6MWD have failed to accurately predict the 6MWD due to variations in population ethnicity and geography.

The aims of this study were 1) to measure 6MWD in healthy North Indian adult males, 2) to determine the applicability of Enright and Sherrill's reference equation to healthy North Indian adult males, and 3) to develop a regression equation for Indian males.

After physical examination and investigations, the 6-minute walk test was conducted in male subjects aged 40-60 years.

The mean (±SD) 6MWD was 536.1 ± 46.9 m. Enright and Sherrill's reference equation did not correctly predict distance in an Indian population: walk distance was overestimated by a mean (±SD) of 46.8 ± 32.9 m. The regression equation developed for males was 6MWD (m) = 3.654 × height (cm) - 4.139 × age (years) + 127.121, and accounted for 63.9% of total variance.

Enright and Sherrill's equation cannot be used to predict the 6MWD in healthy North Indian adult males. The new regression equation is expected to prove useful for various purposes in healthy North Indian adult males.