Real Time Bioelectrical Impedance Analysis: Introduction


Real-time monitoring of impedance changes with an RJL Systems Quantum Desktop

Quantum-II Desktop BIAThe most common use of Bioelectrical Impedance Analysis or BIA is to determine human body composition. While BIA is a well known technology, it is actually only one application of a much larger science known as “Impedance Plethysmography. Impedance Plethsymography is the science of measuring electrical impedance changes of a biological substance or organism over time.

When a BIA instrument is used for body composition analysis, a single measurement is taken. The results are then applied to an algorithm to estimate current body composition. Over time, subsequent measurements are taken and then used to observe trends. These serial measurements are often taken at regular intervals to develop a more precise picture of the changes in the body composition of an individual.

The essays located within this section describe experiments that were designed to illustrate concepts which are key to developing an understanding of impedance plethysmography in general and more specifically BIA. The experiments demonstrate the sensitivity of RJL BIA instruments to measure changes in resistance and reactance of any biological substance, living or dead.

All of these experiments were performed with an RJL Systems Quantum Desktop BIA System. This instrument may be used as both a body composition analyzer and a real time BIA data logger. In either mode, it can send its data to a host computer in real time, or data can be stored internally for download at a later date. It is capable of rapid data acquisition, with only milliseconds between samples, or it can wait several days between collecting data points.

Our intention is to continue to experiment and share the results by adding new essays to this collection. The objective is to increase knowledge and interest in new BIA applications. View Experiment 1.0