Phase angle is associated with cardiorespiratory fitness and fat-free mass in children aged between 9 to 11 years

ABSTRACT Phase angle is a marker of health and cellular integrity and is used as a tool for predicting nutritional status in children with various health conditions. Despite the fact that physical activity and cardiorespiratory fitness have been shown to provide several health benefits, few studies have evaluated the relationship between phase angle and health parameters, e.g., cardiorespiratory fitness and body composition. Thus, we aimed to evaluate the association between phase angle and cardiorespiratory fitness in children aged between 9 to 11 years. Twenty-three children (52% girls) were tested in a cross-sectional study. Bioelectrical impedance analysis provided resistance and reactance values to calculate the phase angle. Body fat (BF) and fat-free mass (FFM) were measured by dual-energy x-ray absorptiometry. Cardiorespiratory fitness (VO2 max) was performed using the 20-meter shuttle-run test. Pearson's correlation was used to test the association between phase angle, cardiorespiratory fitness, and body composition [BF (kg and %BF) and FFM]. Linear regression analysis was used to test the determinant effect of cardiorespiratory fitness values on the phase angle. There was no difference based on the sex of the participants. Phase angle was positively associated with cardiorespiratory fitness (r=0.46) and FFM (r=0.56). We found no association between phase angle and either BF (r=0.056, p=0.801) or %BF (r=-0.235, p=0.280). The cardiorespiratory fitness was inversely associated with BF (r=-0.55) and %BF (r=-0.69). We concluded that phase angle was associated with cardiorespiratory fitness and FFM in children. These results reinforce the importance of promoting health behavior related to exercise and body composition during childhood.