Interferential electrical stimulation improves peripheral vasodilatation in healthy individuals: A randomized crossover study

Background: Interferential electrical stimulation (IES) increases cutaneous blood flow. It is not known whether increases in blood flow may be mediated by muscle metaboreflex activity. Objective: The purpose of this study was to determine the effect of IES on metaboreflex activation in healthy individuals. Design. Acute intervention study with randomized design. Setting. Cardiovascular research laboratory. Patients. Eleven healthy subjects (age 25±1.3 years). Intervention. Interferential electrical stimulation or placebo stimulus (same protocol without electrical output) applied at the ganglion region previously to exercise. Measurements. Mean blood pressure (MBP), Heart Rate (HR), calf blood flow (CBF) and calf vascular resistance (CVR) were measured throughout exercise protocols (submaximal static handgrip exercise), and recovery periods with or without Postexercise Circulatory Occlusion (PECO+ and PECO-, respectively). Muscle metaboreflex control of calf vascular resistance was estimated by subtracting the area under the curve when circulation was occluded from the AUC without circulatory occlusion. Results: At the exercise peak, increases in mean blood pressure were attenuated by IES (p < 0.05), which persisted during PECO+ and PECO-. IES promoted higher CBF and lower CVR during exercise and recovery. Likewise, IES induced a reduction in the estimated muscle metaboreflex control in subjects (Placebo: 21±5 units versus IES: 6±3, p < 0.01). Limitations. No stimulation was provided as a placebo stimulus, since we are unaware of any device to promote a sham intervention without any level of neuromodulation. Conclusions: Acute application of IES previously to exercise attenuates blood pressure and vasoconstrictor responses during exercise and metaboreflex activation in healthy subjects.