Interferential electrical stimulation improves peripheral vasodilatation in healthy individuals

Abstract

| Background: Interferential electrical stimulation (IES), which may be linked to greater penetration of deep tissue, may restore blood flow by sympathetic nervous modulation; however, studies have found no association between the frequency and duration of the application and blood flow. We hypothesized that 30 min of IES applied to the ganglion stellate region might improve blood flow redistribution. Objectives: The purpose of this study was to determine the effect of IES on metaboreflex activation in healthy individuals. Method: Interferential electrical stimulation or a placebo stimulus (same protocol without electrical output) was applied to the stellate ganglion region in eleven healthy subjects (age 25±1.3 years) prior to exercise. 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 with 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 area under the curve from the AUC without circulatory occlusion. Results: At peak exercise, increases in mean blood pressure were attenuated by IES (p<0.05), and the effect persisted under both the PECO+ and PECO-treatments. IES promoted higher CBF and lower CVR during exercise and recovery. Likewise, IES induced a reduction in the estimated muscle metaboreflex control (placebo, 21±5 units vs. IES, 6±3, p<0.01). Conclusion: Acute application of IES prior to exercise attenuates the increase in blood pressure and vasoconstriction during exercise and metaboreflex activation in healthy subjects.

Investigating Hemodynamic Responses to Electrical Neurostimulation

“…C7 and T4, the thigh, or the forearm. Reductions in MAP, CVR, and ischemic pain, as well as increases in CBF were witnessed in these studies [124][125][126].…”

“…As far as we know, there have been no direct comparisons of the effect of IFC and TENS on the cardiovascular system, although separate studies of IFC and TENS using almost identical protocols have been conducted, but the authors only mentioned that similar results were obtained, i.e. reductions in MAP and calf vascular resistance with simultaneous increases in calf blood flow [81,126]. One of the goals of this study was to investigate these two neurostimulation techniques and determine which elicited greater hemodynamic changes, which will be discussed in more detail in Chapter 5.…”

Sweep Frequency of Interferential Currents Therapy Attenuate Fatigue of Biceps Brachia Muscle in Normal Male Subjects: A Randomized Placebo Control Trial

“…The analgesic effect produced by IFC stimulation was attributed to its effect on the local blood supply that reduced the pain inducing chemicals from the site of pathology [21,22].The descending suppression mechanism of pain by endogenous opiates is also determined to modulate pain experience [17,37] and the muscle relaxation induced by IFC therapy [38]. [38] found that the electromyography activity of upper trapezius reduced by interferential current at sensory level with frequency 35 Hz and 75Hz through improving circulation.…”

“…The decline in muscle strength and pain that combined with SMF is thought due to deficiencies in substrate bio-availability, blood flow, and tissue oxygenation, as well as the accumulation of metabolites and neuromuscular alterations [20]. There is evidence from research studies that IFC therapy enhance blood flow with modulated frequency of 10-20 Hz [21,22], relief pain by several mechanisms utilizing high and low frequency [23,24],reduces inflammatory pain [25] and muscular activity at low frequency with sensory level stimulation [26]. According to the author knowledge, no published randomized controlled trial has investigated the effect of sweep frequency IFC therapy to attenu muscle that can occur at any sites within the neuromuscular system and it develops gradually soon after the onset of the sustained physical activity [3].…”

“…A complete health screening questionnaire was required prior to the study. This sample size was chosen based on a priori sample size calculations using = 0.05, power of 80% and an effect size of 0.15 for the measured parameters [11,12,21]. All subjects who had an interest in the study were informed by the experimental procedure (both verbally and in written form) and were screened for contraindications to electrotherapy such as peripheral vascular abnormalities, hyper and hypotension, peripheral neuropathies, recent trauma.Other exclusion criteria consisted of any previous musculoskeletal injury or pain to the shoulder, elbow or wrist regions; regular strength training (more than once per week) for the previous 3 months; the use of any kind of nutritional supplement or pharmacological agent; suffered from unstable cardiovascular, pulmonary conditions or other health problems.…”