An alternative way of measuring hand-to-foot single frequency bioimpedance

The effect of change of position on bioelectrical resistance measurements was studied. 25 individuals of Asian Indian ethnicity (13 men and 12 women; 49-76 years old) underwent bioimpedance measurements using BIM4 in the standing position (S1), in the supine position (L) and again in the standing position after (S2). The mean resistance in S1, S2, and L was 582.4±82.3 Ω, 576.9 Ω and 588.9 Ω, respectively. Paired t-test showed a significant difference between L and both S1 and S2 (P<0.0002), but no difference between S1 and S2. The mean difference was 1.1% between L and both S1 and S2. Further analysis revealed that a difference in either 10 Ω or 1.0 cm of height resulted in a difference of only 0.5-0.6% body fat, suggesting that slight variation when measuring height can generate similar differences in body fat percentage as observed between standing and lying measured impedance values.