Comparison of selected pulse frequencies from two different electrical stimulators on blood flow in healthy subjects.

The purpose of this study was to measure the effects of selected frequencies from two different pulsed electrical stimulators on blood flow, blood pressure, and heart rate. Each of 30 healthy subjects attended 10 study sessions: 1 torque-testing session, 1 control session consisting of no electrical stimulation (ES), and 8 sessions of ES. All subjects received ES at an intensity sufficient to produce torque equal to 15% of the predetermined maximal voluntary contraction of their right quadriceps femoris muscle. The results of a multivariate analysis of variance showed that changes in blood flow during and after ES were dependent on pulse frequency but independent of stimulator type. Further analysis showed significant increases in blood flow with ES using 10, 20, and 50 pulses per second compared with 1 pulse per second. Inconsistent changes in blood pressure and heart rate were produced by ES. Based on the results of this study, effective clinical use of ES for promoting arterial blood flow to muscle would involve pulsed frequencies of 10 to 50 pulses per second.