Influence of different durations of electroacupuncture stimulation on skin blood flow and muscle blood volume

Objective To determine whether skin blood flow (SBF) and muscle blood volume (MBV) responses differ according to the duration of electroacupuncture (EA) stimulation. Methods Two experiments were conducted. In Experiment 1, healthy male students (n=20) were randomly divided into two groups (an EA group and a no-stimulation group). In Experiment 2, healthy male students (n=37) were randomly divided into three groups with different stimulation durations of EA (5, 10 and 15 min). EA stimulation on the quadriceps femoris muscle was administered with a frequency of 1 Hz. SBF and MBV were estimated before, during and after stimulation. Results In Experiment 1 there was a significant difference between the groups (p=0.001). In the EA stimulation group, MBV increased immediately following EA (p=0.045) and 5 min (p=0.005) and 10 min (p=0.002) after EA compared with baseline. No significant change was observed in the no-stimulation group. In Experiment 2 there was no significant difference between the groups. All three stimulation durations (5, 10 and 15 min) yielded increases in MBV after stimulation compared with baseline. SBF following stimulation for 5 and 10 min was increased compared with baseline. Conclusions Based on these findings, we consider that 10 min EA stimulation could be a sufficient duration to induce a blood flow response in a clinical situation when increasing the blood flow is desirable.