Six-minute walking test: Normal reference values for taiwanese children and adolescents

Abstract

Background: The 6-minute walking test (6MWT) is a simple method used to evaluate exercise capacity in adults and children with cardiac diseases. Normal reference values in pediatric populations have been reported, but significant variations in the walking distance (6MWD) were noted among different studies. We aimed to provide and validate normal reference values of the 6MWD for healthy Taiwanese pediatric population between 7 and 17 years of age. Methods: Healthy children and adolescents were recruited from 13 randomly selected schools in Kaohsiung City. From that recruitment effort, 762 participants (50.1% male) were included, and the 6MWT was conducted using standardized protocols. The main outcome measure utilized was the 6MWD, which was used to construct centile charts and Z score equations. Data from additional 64 healthy volunteers recruited from the National Taiwan University Children's Hospital were used to validate these standards. Results: There was an overall linear trend of increase in the 6MWD between 7 and 17 years of age (p < 0.001). Males covered significantly more distance than females after the age of 14 years, when the 6MWD essentially plateaued in female adolescents. Upon multivariate analysis, height was the most significant positive predictor of the 6MWD, while body mass index negatively correlated with the 6MWD. The height-based normal reference values of the 6MWD, derived fromthe 6MWT conducted in the school settings, were validated by a second cohort who received 6MWT inside the hospital. Conclusions: Normal reference values of the 6MWD in healthy Taiwanese children and adolescents may serve as useful references for future clinical and research studies.