The handheld machines sometimes used to measure body fat rely on bioelectrical impedance which estimates your body fat using a painless electrical signal thats sent through your body. A small unnoticeable electrical current is sent from one foot up one leg and down the other leg.

How Bia Works Tanita Corporation
Body fat measurement device how does it work. This body fat measurement test works similar to that of a scale except it doesnt measure your weight. A slower traveling signal usually indicates a higher body fat percent. Fat is a poor conductor of electricity compared to other components of the body such as muscle. For example this method does not measure visceral fat. Various types of body fat analyzers also called impedance meters are available to the general public. The device detects the amount of fat based on the speed at which the signal travels.
Similarly a faster speed indicates less resistance and a lower body fat percent. Body fat scales use a technology called bioelectrical impedance analysis to measure body fat. This method is made possible because a relationship exists between subcutaneous fat and the total amount of body fat3 thus you can estimate total body fat by measuring the fat under the skin. Results from portable body fat analyzers can vary though. While this method can yield good results when done properly it has several drawbacks. There are sensors on either side of the device that measure your body fat as you hold the.
As for accuracy a handheld bia device has about a 35 5 margin of error. Your body fat measurement can depend on many factors such as the devices quality and how hydrated you are when you have the measurement.