2019 Volume 40 Pages 81-89
In the human body, electric resistance varies depending on the temperature of the muscle tissue. In the present study, the effect of cooling on electric resistance was investigated using multi-frequency impedance device while cooling the aorta in the popliteal region in addition to local cooling from the skin surface of the triceps surae. Subjects were ten healthy male students （age: 21.1±1.5 years） of our university. Impedance was measured by the tetrapolar impedance method using a multi-frequency impedance device （MFBIA-07, Tanita） with a frequency at 50 kHz, 100 kHz and 250 kHz. The current （I） electrodes and the sensing （V） electrodes were attached longitudinally to the calf. In order to measure impedance, the distance between the two sensing （V） electrodes were placed at a distance of 15cm. The current electrodes were set at 2cm, 3cm, and 4cm from the V electrode on the distal side. Measurements were obtained following either cooling of the sural region only or cooling of the sural and the popliteal region. During cooling, impedance and skin temperature were measured every 5 minutes for 30 minutes. Temperature was measured at 2cm, 3cm, and 4cm depths from the skin surface of the triceps surae. Under both cooling conditions, a decrease in temperature was observed over time. In addition, the changes in cooling temperature decreased with increase in depth from the skin surface. The effect of cooling was greater while cooling the aorta in the popliteal region than while cooling the sural region only. Therefore, the cooling effect could be enhanced by cooling the aorta on the central side with simultaneous local cooling.
