In vivo electrical characteristics of human skin, including at biological active points

The aim is to compare the mean values of the in vivo electrical characteristics of bioiogical active points (BAPs) with those of the surrounding human skin. The impedance measurements at BAPs and on the surrounding skin are carried out in vivo on ten young, healthy people. The results of the measurements show that the BAP resistance R_P is smaller, and the capacitance C_P is higher, than the corresponding values for skin, R_S and C_S, respectively, these differences are larger at low frequencies (at f=3 Hz, R_S/R_P=3.19 and C_P/C_S=3.2). The mean values of the impedance measurements at the BAPs are different from those measured on the skin. The dependence of R_P and C_P on the pressing force, in the range of about 1–5 N, for the BAPs, has a smaller slope than that observed for the surrounding skin. An equivalent circuit for the BAPs is proposed that describes sufficiently well the experimental results obtained. These results show that the large dispersion in the observed impedance characteristics of the human body measurements in different body regions can be related to the influence of the BAPs present under the electrodes.