| 
Bioelectrical Impedance Analysis (BIA) for Body Composition
In BIA a small electrical current is passed through the body and the impedance (a combination of resistance and reactance) is measured. The theory is that fat, containing very little water, is a poor electrical conductor, while lean tissue, containing mostly water and electrolytes, is a good electrical conductor. Therefore, less impedance means the individual has more lean tissue while more impedance means the individual has more fat. Hydration levels significantly effects the results. The accuracy for BIA is ~ + 3.5-5%body fat. In addition, it tends to overestimate body fat in lean individuals and underestimate body fat in obese individuals. Finally, there is limited data on the accuracy of many of the BIA machines that are now commercially available.
|
