Bioelectrical Impedance Analysis

A relatively easy to administer method of measuring body fat percentage. Bioelectrical impedance analyses works by determining the electrical impedance of the body tissues, which provides an estimate of total body water, which can be used to estimate fat free mass and percentage body fat. It involves the passing of a small electrical current through the body and measuring the impedance to current flow. Fat free tissue is a good conductor of electrical currents, therefore body fat impedes current flow, and the impedance to current flow is inversely related to the fat free mass and total body water, both of which can be estimated by using this technique. Generally bioelectrical impedance analyses yields similar results to skinfold measurements with regards to percentage body fat estimates, but the protocol that MUST be followed by the subject make it a little difficult.

Prior to assessment the subject must do the following to achieve maximum accuracy in results:

  • 4 hours fasting prior
  • No exercise within 12 hours
  • No alcohol within 48 hours
  • Each subject must void completely before assessment
  • Abstain from diuretic agents including caffeine, unless medically prescribed