Reference values of 6 minutes walk test (6 MWT) in Bangladeshi healthy subjects aged 25-55 years

The six minute walk test (6MWT) is increasingly accepted worldwide to assess functional exercise capacity of cardiac and pulmonary diseases for its simplicity. The aim of the present study was to provide reference values for 6 Minute Walk Distance (6MWD) and other primary variables such as oxygen saturation (SaO2), pulse rate (PR) and breathlessness perception done in 6MWT. We studied a sample of 190 healthy subjects (53 females) of age between 25-55 years (37.9 ± 8.5 years). Baseline lung functions including forced expiratory volume in 1st second (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were measured by a flow sensing spirometer. All subjects performed 6MWT according to standard protocol provided by the American Thoracic Society (ATS) guidelines. The fatigue and dyspnoea was measured before and after 6MWT by modified Borg scale. The SaO2 and PR were measured also by a light weight pulse oxymeter. The mean 6MWD was 466.7 ± 69.4 meter, ranging from 213 to 659 meter and the mean Distance Work (DW) was 28732 ± 7024 kg-m. Dyspnoea status and oxygen saturation remained unaltered throughout the walk. Mean resting and walking SaO2 values were, respectively, 97.1 ± 1.3% and 96.8 ± 1.5%: The mean change in SaO2 was 3 ± 1.5%. PR was significantly affected by the walk. Mean resting and maximum PR after walking were respectively, 80 ± 7 and 103 ± 12 bpm (p < .01). Gender significantly affected the 6MWD (p < .01). In all subjects, the 6MWD was inversely and directly related, respectively, to age (r = -.15; P < .05) and height (r = .41; P < .01). This study showed reference values for the 6MWT variables of subjects in Bangladeshi population.