A new equation based on the 6-min walking test to predict VO_2peak in women with obesity

The 6-min walking test (6 MWT) is commonly used to assess obese patients' aerobic fitness, but it has rarely been compared with a direct measurement of maximal aerobic capacities (VO_2max or VO_2peak) in obese adults. The aim of this study was to investigate the relationship between the distance covered during a 6 MWT with objectively measured VO_2peak and to propose a new equation to predict VO_2peak from this walking test in obese patients.

One hundred and thirty-seven obese patients (45.6 ± 12.5 years) admitted to our hospital for a multidisciplinary rehabilitation program were enrolled. After assessment of their body composition, the participants were asked to perform a 6 MWT and their maximal aerobic capacities (VO_2peak) were measured.

There is a significant linear relation between VO_2peak and the distance covered during the 6 MWT (p < 0.001; r = 0.349). The determinant of VO_2peak was body mass index, waist-to-hip ratio, fat free mass, leading to the follow prediction equation VO_2peak such as VO_2peak (l/min) = (body mass index ×0.0150065) - (waist-to-hip-ratio × 0.8595088) + (fat-free-mass × 0.0295478) + (6-min walk test ×0.0020672) - 0.5853372.

The 6-min walk test is a reliable method to reflect obese women's aerobic capacities and the distance covered can be used to accurately estimate VO_2peak according to our newly proposed equation. Implication for rehabilitation Obesity is a worldwide disease and physical capacity evaluation is a key point for rehabilitation. The six minutes' walk test is commonly used in obese people to assess aerobic fitness. This study proposes a new equation using 6 MWT performance to estimate VO_2peak.