Nao MIYAMOTO, Yusuke SAKAUE, Naruhiro SHIOZAWA
Vol. 13 (2024) p. 82-89

Hypertension affects many people and increases the risk of serious illnesses. Blood pressure (BP) can be reduced by decreasing heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR). We aimed to investigate non-pharmaceutical therapy for reducing hypertension by evaluating the effects of self-administered high-voltage, low-frequency (HV-LF) electrical stimulation of peripheral nerves in the limbs. The hypothesis was that such stimulation would induce a decrease in HR and increase skin blood flow (SBF), leading to a decrease in BP. A crossover trial was used to verify the effects of stimulation of the median nerve (SMN) and superficial peroneal nerve (SSPN) in 16 healthy adult male participants. Patients with hypertension were excluded from the study. Stimulation was performed at 1 Hz for 20 s using an electrical stimulator capable of generating high voltage using a piezoelectric element. HR, SV, and CO were evaluated as parameters of circulatory dynamics, while SBF was an indicator of peripheral blood flow. TPR was calculated from BP and CO values. BP was significantly lower following both SMN and SPPN. In SMN, an immediate decrease in HR and an increase in SBF were observed. In SPPN, transient decreases in HR and CO and an increase in SBF were observed. Thus, both stimuli affected circulatory dynamics and local blood flow, supporting the hypothesis. However, TPR remained unchanged, indicating that the effect of blood pressure reduction was mainly due to central circulation suppression rather than SBF. The decreases in HR and BP were similar in the SMN and SSPN groups; however, CO and SBF showed different response trends in the two groups. This difference suggests that the primary factors that decrease BP may differ between SMN and SSPN, and that this should be investigated further. Thus, self-administered HV-LF electrical stimulation of superficial skin nerves, as used in this study, may be useful as a novel non-pharmacological intervention for the treatment of hypertension, although further studies are needed to optimize stimulation parameters in patients with hypertension.