What is a common limitation of using bioelectrical impedance analysis for body composition assessment?

Bioelectrical impedance analysis (BIA) is a popular method for assessing body composition, particularly body fat percentage. One common limitation of this method is its sensitivity to hydration status. When a person's hydration levels change, the conductivity of body tissues can also change, which can lead to inaccurate estimates of body fat. For example, dehydration can cause lower fluid levels in the body, resulting in a higher impedance measurement and thus an overestimation of body fat. Conversely, overhydration can lead to lower impedance measurements and an underestimation of body fat.

Considering this, BIA results can vary significantly depending on when and how the assessment is conducted, as well as the individual's hydration status at the time of measurement. This highlights the importance of standardizing conditions under which BIA is performed to improve accuracy and reliability.