Six-minute walking distance in healthy Chinese people older than 60 years

Abstract Background: The six-minute walking test (6MWT) is a tool that is widely used to evaluate exercise capacity in clinical practice and research. However, to date, there are no standard reference equations for the six-minute walking distance (6MWD) for people aged 60-85 years in China. The purpose of this study was to 1) measure the 6MWD of healthy Chinese people aged 60-85 years, 2) establish prediction reference equations for the 6MWD, and 3) compare our reference equations with those reported in previously published studies.Methods: We obtained verbal informed consent from all subjects prior to the trial and the Ethics Committee of Wenzhou People's Hospital approved the design of the study. The demographic and anthropometric data and the 6MWT results of healthy Chinese subjects aged 60-85 years were measured by a standardized protocol. The subjects completed two 6MWTs monitored by the same operator. The second 6MWT was completed in 2 hours and the longer 6MWD was used for further analysis. Results: A total of 266 subjects (128 male and 138 female) completed the 6MWTs, and the mean 6MWD for all subjects was 502.0±72.86 m. Males achieved a longer 6MWD than females (518.0±72.3 m vs. 487.2±70.44 m; p<0.0001), and physically active subjects achieved a longer 6MWD than sedentary subjects (512.2±76.33 m vs. 484.5±63.11 m; p<0.0001). Univariate linear regression analysis showed that variables (i.e., age, height, body mass index (BMI), post-test heart rate, blood pressure, post-exercise heart rate changes, etc.) were significantly associated with the 6MWD. Age, height, and BMI were identified as independent factors that influenced the 6MWD and could explain approximately 33% of the walking variance. The reference equations from Caucasian and South Americans tended to overestimate the 6MWD of our subjects, while the equations from Asians and Africans often underestimated the 6MWD of our subjects.Conclusions: In this study, the 6MWD of healthy people aged 60-85 years in China was described for the first time, and prediction reference equations for the 6MWD were proposed. This will help to improve the diagnosis and treatment of elderly Chinese patients with diseases that affect exercise capacity.