The six-minute walk test and body weight-walk distance product in healthy Brazilian subjects

Abstract

We assessed the 6-min walk distance (6MWD) and body weight x distance product (6MWw) in healthy Brazilian subjects and compared measured 6MWD with values predicted in five reference equations developed for other populations. Anthropometry, spirometry, reported physical activity, and two walk tests in a 30-m corridor were evaluated in 134 subjects (73 females, 13-84 years). Mean 6MWD and 6MWw were significantly greater in males than in females (622 ± 80 m, 46,322 ± 10,539 kg . m vs 551 ± 71 m, 36,356 ± 8,289 kg . m, P < 0.05). Four equations significantly overestimated measured 6MWD (range, 32 ± 71 to 137 ± 74 m; P < 0.001), and one significantly underestimated it (-36 ± 86 m; P < 0.001). 6MWD significantly correlated with age (r = -0.39), height (r = 0.44), body mass index (r = -0.24), and reported physical activity (r = 0.25). 6MWw significantly correlated with age (r = -0.21), height (r = 0.66) and reported physical activity (r = 0.25). The reference equation devised for walk distance was 6MWD m = 622.461 -(1.846 x Age years ) + (61.503 x Gender males = 1; females = 0 ); r 2 = 0.300. In an additional group of 85 subjects prospectively studied, the difference between measured and the 6MWD predicted with the equation proposed here was not significant (-3 ± 68 m; P = 0.938). The measured 6MWD represented 99.6 ± 11.9% of the predicted value. We conclude that 6MWD and 6MWw variances were adequately explained by demographic and anthropometric attributes. This reference equation is probably most appropriate for evaluating the exercise capacity of Brazilian patients with chronic diseases.

Critical review of the equations predicting 6-minute walking distance in obese subjects

“…Original Article studies are reported in Table 1. In particular, two equations [29,31] had been specifically developed for obese subjects, while in other eight studies [18,26,[35][36][37][38][39][40] both obese (BMI ≥30 kg/m 2 ) and non-obese subjects were enrolled. In four papers [20,25,34,41] no information was available with respect to the presence or absence of obese subjects in the study sample.…”

“…Variables included in the equation R 2 Alameri H et al [35] Age, Height 0.25 Ben Saad H et al [36] Gender, age, weight, height 0.77 Camarri B et al [37] Gender, age, weight, height 0.36 Capodaglio P et al [29] Gender, age, BMI 0.48 Casanova C et al [40] Age, height, weight, HR 0,38 Chetta A et al [34] Gender, age, height 0.42 Enright PL & Sherrill DL [18] Gender, age, weight, height (or BMI) 0.42 M, 0.38 F Enright PL et al [20] Gender, age, weight, height 0.20 Gibbons WJ et al [25] Gender, age 0.41 Iwama AM et al [38] Gender, age 0.30 LarssonUE et al [31] Gender, height, BMI, final HR, HR at rest, 0,71 Masmoudi K et al [41] Gender, age, weight, height 0.60 Poh H et al [39] Age, weight, height, hearth rate 0.78 Troosters T et al [26] Gender, age, weight, height 0.66…”

Strength of the respiratory and lower limb muscles and functional capacity in chronic stroke survivors with different physical activity levels

“…The distances covered during the 6MWT, which appropriately reflect the physical capacity to perform daily tasks, were registered for analyses [22][23][24] . The test was carried out, following the procedures and recommendations of the American Thoracic Society 25 , which were adapted to the Brazilian Portuguese language 26 .…”

Reproducibility of step tests in patients with bronchiectasis

“…The outcome was the distance traveled, and the test with the higher value was selected. The distance was expressed in absolute values and as percentages of the predicted values 22 .…”