What is bioelectrical impedance (BIA) mainly limited by?

The primary limitation of bioelectrical impedance analysis (BIA) is its sensitivity to hydration levels. When conducting a BIA assessment, the accuracy of the measurements can be significantly influenced by the individual's hydration status. This technique works by sending a small electrical current through the body and measuring the resistance encountered, which varies depending on the amount of water in the tissues. If a person is under-hydrated or over-hydrated, it can lead to inaccurate readings of body composition, particularly body fat percentage and lean body mass.

This means that for BIA results to be reliable, proper hydration before the test is essential, making hydration an important factor to consider for both the individual being assessed and the accuracy of the overall method. Therefore, understanding and controlling for hydration is crucial when using BIA for health and fitness evaluations.