What measurement technique can be used to estimate total body water?

Bioelectrical Impedance Analysis (BIA) is a measurement technique utilized to estimate total body water. This method works by sending a low-level electrical current through the body and measuring the resistance to the flow of this current. Because water is a good conductor of electricity, the amount of resistance encountered correlates directly with the body's water content. Since lean tissue, which contains a higher percentage of water, conducts electricity better than fat tissue, BIA can effectively distinguish between the different compartments of body composition, thus providing an estimate of total body water.

Other methods like Body Mass Index (BMI) primarily assess weight relative to height and do not directly measure body water or composition. Waist measurement, while useful for evaluating abdominal fat distribution, does not provide any information about overall body water levels. DEXA scans are advanced imaging techniques that measure bone density, body fat, and lean mass distribution, but they are not primarily designed to estimate total body water. Thus, BIA is the most appropriate method among the options provided for estimating total body water.