ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2022 February;62(2):163-9

DOI: 10.23736/S0022-4707.21.11877-8

Copyright © 2021 EDIZIONI MINERVA MEDICA

lingua: Inglese

Hemodynamic responses to neuromuscular electrical stimulation and to metaboreflex activation

Aline C. DE MACEDO ^{1, 2, 3}, Andressa S. SCHEIN ^{2, 3}, Carine C. CALLEGARO ⁴, Vinícius M. ALVES ^{3, 5}, Paula M. ZAMBELI ^{2, 3}, Graciele SBRUZZI ^{2, 3}, Beatriz D. SCHAAN ^{1, 2, 3, 6} ✉

¹ School of Medicine, Graduate Program in Health Sciences, Cardiology and Cardiovascular Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; ² Federal University of Rio Grande do Sul, Porto Alegre, Brazil; ³ Physiopathology of Exercise Laboratory, Clinical Hospital of Porto Alegre, Porto Alegre, Brazil; ⁴ Physiology and Rehabilitation Laboratory, Federal University of Santa Maria (UFSM), Santa Maria, Brazil; ⁵ Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Brazil; ⁶ School of Medicine, Department of Internal Medicine, Graduate Program in Medical Sciences, Endocrinology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil

BACKGROUND: Metabolites produced during muscle exercise can sensitize types III and IV fibers, which account for increasing blood pressure (BP) and vascular resistance in non-exercising limbs, as well as for redistributing the blood flow to active muscles; reflex response is called metaboreflex. Neuromuscular electrical stimulation (NMES) induces greater local muscle metabolic demand than voluntary isometric contractions. Metabolic accumulation is essential to activate muscle metaboreflex; thus, the hypothesis of the current study is that one NMES session can induce metaboreflex with different hemodynamic responses in upper and lower limbs. Objective: to investigate whether one acute NMES session could activate metaboreflex by inducing different hemodynamic responses between arms and legs.
METHODS: Twenty (20) healthy subjects (mean age = 47.7±9.4 years, 13 women, mean body mass index = 26 ± 3 kg/m²) participated in this randomized crossover study. All participants were subjected to two NMES interventions, one in the upper limbs (UPL) and the other in the lower limbs (LL). Mean blood pressure (MBP), blood flow (BF) and vascular resistance (VR) were used to selectively evaluate metaboreflex responses at baseline, during NMES interventions, and recovery periods with, and without, postexercise circulatory occlusion (PECO+ and PECO-, respectively) through the area under the curve (AUC) in VR.
RESULTS: MBP increased by 13% during UPL interventions and only remained high during PECO+. Changes in MBP were not observed in LL, although BF in the contralateral leg has decreased by 14% during PECO+ protocol. Muscle metaboreflex activation (AUC differences in VR between PECO+ and PECO-) was not different between UPL and LL (P=0.655).
CONCLUSIONS: Acute NMES session has induced similar metaboreflex activation in both arms and legs, although hemodynamic responses differed between interventions.

KEY WORDS: Electric stimulation therapy; Blood pressure; Vascular resistance; Regional blood flow; Exercise therapy