Influence of steps per day on health-related quality of life in schoolchildren: the mediator role of cardiorespiratory fitness

Abstract

Abstract Objectives To analyse the relationship between steps per day and HRQoL and cardiorespiratory fitness (CRF) and to examine whether the relationship between steps per day and HRQoL is mediated by CRF in schoolchildren. Methods This was a cross-sectional study including 501 schoolchildren (aged 9–12 years, 47.3% girls), from Cuenca, Spain. Steps per day were measured using the Xiaomi MI Band 3 Smart Bracelet, HRQoL was estimated by the KIDSCREEN-27 questionnaire and CRF was assessed using the 20-m shuttle run test. Results ANCOVA and MANOVA models showed that children with a higher mean number of steps per day (> 9,000 steps/day) had better HRQoL (global score and physical and psychological well-being) and higher CRF levels than their peers with a lower number of steps per day (p < 0.05); however, these differences were attenuated when controlling for sex, age, mother’s education level and CRF (p > 0.05). Linear regression models estimated that each 1000-step increment was associated with better CRF (β = 0.350). In addition, the relationship between steps per day HRQoL global score and physical and psychological well-being is partially mediated by CRF (p < 0.05). Conclusion Steps per day is a good metric to estimate daily physical activity because of its positive relationship with CRF. Moreover, those children taking more than 9,000 steps per day have better physical and psychological well-being. Finally, a substantial part of the improvement in HRQoL achieved through the increase in physical activity (steps per day) is mediated by CRF.