Thursday, February 17, 2011

Lose More than 2 Pounds of Fat-Mass in Less than 30 Minutes: The Illusiveness of Bioelectrical Impedance Analysis

Wouldn't it be nice to burn more than 2 pounds of body-fat within 30 minutes of exercise? Well, according to your body impedance scale this is easily possible! You would even gain 1 pound of solid muscle...

In a recent study Selma Civar Yavuz (Yavuz. 2011) had 52 healthy volunteers perform an exhaustive treadmill exercise (Bruce test) and evaluated the body composition changes by the means of bioelectrical impedance analysis. The results summarized in Table 1 are amazing:
Table 1: Comparison of the body mass index (BMI), fat mass (FTM), fat free mass (FFM), total body water (TBW) and bioelectrical impedance measurements taken before and after the exercises.
What is amazing about these results is yet not the amount of fat the subjects burned in <30 min of running. Its rather the inaccuracy of the impedance analysis. In view of the results of this study you better throw your expensive body-fat scale out of the window and revert to using an old fashioned tape measure to evaluate your dieting / exercise success.