What is bioelectrical impedance?

Bioelectrical impedance is a technique used to estimate body composition by measuring how electricity flows through body tissues. When a small electrical current is passed through the body, different types of tissues, such as fat, muscle, and water, exhibit varying levels of resistance to that current. This resistance, or impedance, can be measured, and from these measurements, data about body composition—including the percentage of body fat, lean body mass, and hydration status—can be inferred.

This method is popular because it is relatively quick, non-invasive, and can be performed using portable devices. It leverages the principles that fat tissue contains less water and thus is less conductive than muscle tissue, which has a higher water content and is more conductive. As a result, the resistance measurement provides valuable insights into a person's body composition, making it a useful tool in health and fitness assessments.