Effects of Functional Electrical Stimulation on Metaboreflex Activation in Healthy Individuals

Hospital de Clinicas de Porto Alegre

Status and phase: Unknown; Early Phase 1

Conditions: Reduction of Blood Flow

Treatments: Other: Isometric exercise; Other: Functional electric stimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT02448030

14-0359

Details and patient eligibility

About

Cardiovascular exercise adjustments are required during in order to redistribute blood flow from non-exercising vascular areas to active muscles. This hemodynamic adjustments, which are partially mediated by mechanosensitive and metabosensitive reflexes, ultimately increase oxygen and nutrient delivery to exercising muscle tissues (Mitchell, 1990). Static handgrip exercise has been shown to induce alterations in the arterial baroreflex function (Kim, 2005) and activation of muscle metaboreflex that increases arterial blood pressure and peripheral vasoconstriction, respectively. Functional electrical stimulation (FES) treatment used in physical therapy in patients who are unable to tolerate conventional exercise showed to be a good alternative for muscle strengthening (Sbruzzi, 2010) and to improve metabolic abnormalities (Karavidas, 2006). However, the effect of FES on metaboreflex activation in healthy individuals has never been investigated. Therefore, this study aims to evaluate the metaboreflex activation induced by FES in upper and low limbs in healthy individuals, and also to compare their results with the effects caused by isometric exercise.

Full description

All participants will be invited to attend four separate days for completion of the study protocols. On the first day, the metaboreflex activation in upper limb will be randomly assigned to isometric exercise or FES intervention. On the second day, at least two days apart, random isometric exercise or FES intervention will be performed in the upper limb. On the third day, at least one week apart, all participants will be assigned to perform metaboreflex in a lower limb induced by isometric exercise or FES intervention. On the fourth day, at least two days apart, random isometric exercise or FES intervention will be performed in a lower limb. To evaluate the isometric exercise and FES intervention the post-exercise ischemia will be randomly performed to evaluate the accumulation of metabolites in response to activated limb (PECO +) and evaluation control without ischemia (PECO-). The experiments between PECO+ and PECO- will be separated by a 30 min interval. During isometric exercise and FES protocols the blood flow and peripheral vascular resistance will be assessed by venous occlusion plethysmography. Fatigue will be determined every minute by the 10-point Borg scale to assess rate of perceived exertion and by blood lactate. Blood lactate will be evaluated through capillary action at pre, immediately post exercise and at 5 minutes during the recovery period. Hemodynamic variables such as BP and HR will be recorded every minute during the protocols.

Enrollment: 20 estimated patients

Sex: All

Ages: 35 to 70 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy individuals
• Both genders
• Aged 35-70 years
• Sedentary
• Not using continuous medications

Exclusion criteria

• Cardiovascular disease
• Neurological disease
• Malignant disease
• Peripheral vascular disorders (varicose veins or deep vein thrombosis)
• Peripheral sensitivity alterations
• Contraindication to performing physical exercise
• Refusal to sign the consent form

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Single Blind

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20 participants in 2 patient groups, including a placebo group

Functional electric stimulation

Experimental group

Description:

Other: The FES will be placed at the flexor muscles of the forearm and knee extensors, for evaluation of upper and lower limbs, respectively.

Treatment:

Other: Functional electric stimulation

Isometric exercise

Placebo Comparator group

Description:

For the upper limbs the isometric contraction exercise with handgrip will be performed for 5 minutes with 30% of loading, previously measured by maximum voluntary contraction test.

Treatment:

Other: Isometric exercise