Bioelectrical impedance analysis: a review of principles and applications.

Whole-body bioelectrical impedance analysis (BIA) is widely used by researchers and clinicians as a noninvasive and safe method to estimate body composition and body water volume in children and adults. Development of new approaches, such as segmental and multifrequency analyzers, should greatly expand the utility of this electrical technique. This article reviews the principles, underlying assumptions, clinical applications and future directions of the BIA method.