EFFECT OF BODY POSTURE ON SEGMENTAL MULTIFREQUENCY BIOIMPEDANCE VARIABLES

Abstract

Integrating measured data from different body postures is important for merging diverse clinical data from segmental multifrequency (SMF) bioimpedance analysis (BIA) and generating reference data. The purpose of this study was to evaluate the effects of changes in posture when measuring raw bioelectrical parameters based on body segment and frequency at various locations in healthy adults. In this study, InBody S10, an SMF-BIA device, was used, and the reliability of the device was verified using the intraclass correlation coefficient of repeated measurement results according to the change in the measurement posture. Measurements were performed in the supine, sitting, and standing positions, and resistance and reactance measured in the changed positions were compared. The supine position exhibited the highest resistance for all body segments and frequencies as well as the highest arm reactance. Resistance decreased monotonically with frequency. In contrast, the reactance of the legs and trunk in the supine position changed its phase above a critical frequency compared to that in the standing and sitting posture. Due to the influence of measurement posture on bioimpedance, regression models between different postures were proposed with body segments and frequencies that enable directly comparing or merging data obtained from various postures. The fit of the linear regression model, which can be used to convert the results from sitting and standing postures to the supine position, was 0.6 or greater. This study elucidates the effect of postural changes on SMF-BIA and enables combining SMF-BIA indicators with positional changes.