Describe how bioelectrical impedance analysis (BIA) works. What are some of the challenges of using ...

BIA is a method of determining body composition that involves sending a very low level of electrical current through a person's body. Water is a good conductor of electricity and lean body mass is made up of mostly water. Thus, the rate at which electricity is conducted gives an indication of a person's lean body mass and body fat. This method can be done while lying down, with electrodes attached to the feet, hands and the BIA machine.

One of the challenges of the BIA method is that the person being measured must follow certain guidelines to improve accuracy of the test. This includes not eating for 4 hours and no exercise for 12 hours prior to the test, and no alcohol consumption within 48 hours of the test. Females should not be measured if they are retaining water because of menstrual cycle changes.

Another challenge is that most places that offer BIA only use one prediction equation for all clients; this limits the accuracy of the BIA method.