Evaluation of a new impedancemeter to independently measure extracellular, intracellular and total body water volumes: application to the measurement of hydration

Abstract

The objective of this study was to evaluate the accuracy of independent hydric data for the quantification of total body water (V _t), extracellular water (V _e) and intracellular water (V _i), obtained by a multifrequency impedancemeter Z-Métrix^® (ZM), in standing and lying position, with respect to the Xitron reference. In a second step, the aim was to consider whether it is possible to quantify daily hydration. The average repeatability error of the ZM impedancemeter is less than 0.5 %. For total body water (V _t), we note a low R ² dispersion with an average of 0.9 for men and 0.6 for women. The estimation of extracellular water is equivalent to a maximum error of 3.1 % in standing position for women against 2.97 % for men in the same position. The estimation of the total body water by direct measurement and by summing the volumes of extracellular and intracellular water obtained by the Z-Metrix^® shows very low dispersions with R ² = 0.89 and average error from 1.3 % for healthy women in lying position to 3.9 % for healthy women in standing position. Finally, despite the impact of events on the daily measurements, it is viable to track a subject’s overall hydration.