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 characteris tics of biological active points (BAPs) with those of the surrounding human skin. The impedance measurements at BAPs and on the surrounding skin are c arried out in vivo on ten young, healthy people. The results of the measure ments 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, respectivel y, 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 BAP s 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 c ircuit for the BAPs is proposed that describes sufficiently well the experi mental results obtained. These results show that the large dispersion in th e observed impedance characteristics of the human body measurements in diff erent body regions can be related to the influence of the BAPs present unde r the electrodes.