Mirele Savegnago Mialich^1,, Juliana Maria Faccioli Sicchieri², Alceu Afonso Jordao Junior²

Bioelectrical impedance analysis (BIA) is a method extensively used in studies assessing body composition, especially in view of the high speed of information processing, as a noninvasive method for generating information through portable, easy to use and relatively inexpensive equipment that estimates the distribution of body fluids in the intra- and intercellular spaces in addition to the body components. This technique consists of the passage of a painless low amplitude electrical current applied through cables connected to electrodes or to conducting surfaces placed in contact with the skin, permitting the measurement of resistance (R) and reactance (Xc). These R and Xc values applied to mathematical equations permit the estimate of the following body compartments: fat mass (FM), fat-free mass (FFM) and total body water (TBW). In this respect, the objective of the present report is to review the main concepts involved in the BIA technique, to describe the types of BIA available, their limitations and applications to clinical practice, especially the monitoring of chronic diseases. After this review, we conclude that BIA is an important instrument for health professionals and that its use can provide safe data about body composition, in addition to complementary data about the clinical course of patients followed up on a medium- and long-term basis.

body composition, bioelectrical impedance, resistance, reactance, fat mass, fat-free mass, body water