Phase angle is associated with cardiorespiratory fitness and body composition in children aged between 9 and 11 years

Abstract

Phase angle (PhA) is a marker of health and cellular integrity and is used as a tool for predicting nutritional status in children with various health conditions. Even though physical activity and cardiorespiratory fitness have been shown to provide several health benefits, few studies have evaluated the relationship between PhA and health parameters, i.e., cardiorespiratory fitness and body composition. Thus, we aimed to evaluate the association between PhA and cardiorespiratory fitness in children aged between 9 and 11 years. Twenty-three children (52% girls) were tested in a cross-sectional study. The PhA was calculated by bioelectric impedance parameters. Body fat (BF) and fat-free mass (FFM) were measured by dual-energy absorptiometry. Cardiorespiratory fitness (VO2 peak) was performed using the 20-meter shuttle-run test, and allometric scaling were calculated to better control the effect of body weight (VO2 peak BW), BF (VO2 peak BF) and FFM (VO2 peak FFM) on fitness. All analyses were performed separately for each sex group. Pearson's correlation was used to test the association between PhA, cardiorespiratory fitness (relative and absolute), and body composition [BF (kg and%) and FFM]. Linear regression analysis was used to test the determinant effect of cardiorespiratory fitness values on PhA. In girls, the PhA was negatively associated with%BF (r = -0.66), and positively associated with FFM (r = 0.68), VO2 peak BW (r = 0.69), and VO2 peak FFM (r = 0.78). While in boys, the PhA was positively associated with VO2 peak BW (r = 0.71), VO2 peak BF (r = 0.75), and VO2 peak FFM (r = 0.70). Linear regression showed an association of VO2 peak FFM on PhA in girls and boys (β = 0.781 and β = 0.703, respectively), and an association of VO2 peak BW and VO2 peak BF on PhA only in boys (β = 0.705 and β = 0.746, respectively). We concluded that PhA was negatively associated with %BF and positively associated with FFM in girls. Furthermore, when allometric scaling was used to better control the effect of body weight, body fat and fat-free mass, the PhA was positive associated with VO2 peak BW, VO2 peak FFM (in girls and boys), and VO2 peak BF in boys. These results suggest that the value of phase angle can be an important parameter to investigate health status related to body composition and cardiorespiratory fitness in children.