Bioelectrical Impedance Analysis

Bioelectrical impedance analysis (BIA) is currently one of the most exact and easiest ways to determine body fat composition. BIA is conducted by attaching electrodes to various parts of the body while a small electrical signal is passed through. BIA is conducted using the weight, height, age, gender, ethnicity, body type, and physical activity level in combination with the measured resistance the body has to the electrical signal. A simpler version of BIA can be found in commercial products similar to the operation of a bathroom scale with the electrodes placed in special foot sensors.

The measured resistance of the electrical signal varies based on the water that is found in muscle and fat. Resistance or impedance is low in lean tissue and high in fat tissue. The measure of resistance is dependent on total body water of an individual. The more muscle an individual has, the greater the amount of water the body contains. The greater the total body water, the easier the current can pass through the body. Although an electrical signal is passed through the body, BIA is considered safe and does not cause pain. The electrical signal used is so small that neither adults nor children have reported feeling it.