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.