Effect of the Combination of Whole-Body Neuromuscular Electrical Stimulation and Voluntary Exercise on Metabolic Responses in Human

Abstract

Purpose Since neuromuscular electrical stimulation (NMES) can recruit high-threshold motor units and enhance glucose metabolism, the combination of NMES and voluntary low-intensity exercise would induce both anerobic and aerobic energy consumptions and this type of exercise could be more efficient and effective than conventional exercise regimens. We aimed to investigate metabolic responses and muscle fatigue during whole body NMES (WB-NMES), voluntary exercise, and their combination. Methods The blood lactate concentration and maximal voluntary contraction were measured before and after specified exercises: WB-NMES (E), voluntary exercise (V), and their combination (VE), and expired gas was sampled during the exercises in thirteen healthy young men. Each exercise was conducted for 15 min and interval between exercise was > 48h. Results Energy expenditure and relative to the body mass during VE were significantly higher than during V and E ( p < 0.05). The Respiratory gas exchange ratio (RER) during both E and VE was higher than during V ( p < 0.05), and the blood lactate concentration after VE was significantly higher than after V and E ( p < 0.05). Although relative to the body mass was 18.6 ± 3.1 ml/min/kg and the metabolic equivalent was 5.31 ± 0.89 Mets, the blood lactate concentration reached 7.5 ± 2.7 mmol/L after VE. Conclusion These results suggest that the combination of WB-NMES and voluntary exercise can enhance the metabolic response to a level equivalent to high intensity exercise under the net physiological burden of low-middle intensity exercises.

Effect of exercise intensity on metabolic responses on combined application of electrical stimulation and voluntary exercise

“…The blood lactate concentration and RER were significantly increased by superimposing NMES onto the voluntary pedaling exercise at various exercise intensities (middle and lower panels in Figure 2). These findings support the results of previous studies (Watanabe et al, 2014, 2019) and could reflect the recruitment of motor unit/muscle fibers contributing to glucose metabolism. However, at 50% of VT, there was no significant difference in the blood lactate concentration between VOL and VOL+NMES (middle panel in Figure 2), and the increase in the blood lactate concentration during VOL+NMES was significantly lower than the net gain in the blood lactate concentration induced by NMES (lower panel in Figure 3).…”

“…Previous studies, including our work, already reported that the combined application of NMES and voluntary aerobic exercises can increase oxygen consumption and enhance glucose metabolism because of the additional NMES-elicited recruitment of motor units that are not activated for given voluntary exercises and/or high-threshold motor units (Kemmler et al, 2012;Watanabe et al, 2014Watanabe et al, , 2019. On the other hand, the benefit of superimposing NMES onto voluntary exercises would be reduced with high-intensity, anaerobic, or resistance exercises in terms of the additional recruitment of motor units and its induced metabolic responses, since any additional recruitment of motor units by superimposing NMES is theoretically impossible when all motor units are fully recruited, as in the case of maximal voluntary contraction (Hortobagyi et al, 1992;Koutedakis et al, 1995).…”

“…On the second day, NMES was administered in a supine position on a bed without performing any voluntary contractions for 3 min (NMES). NMES was applied to anterior and posterior thigh muscles and gluteus muscles using a custommade stimulator based on a commercially developed NMES device (SIXPAD, MTG Ltd., Nagoya, Japan) (Watanabe et al, 2017(Watanabe et al, , 2019 and silicon-rubber electrodes covered by wet patches of material fixed on the inside of fitted shorts ( Figure 1) (Watanabe et al, 2019). NMES for all electrode pairs was synchronized and biphasic square current pulses with a 100-μs duration were then constantly applied with a 4-Hz stimulation frequency.…”

“…During all exercises on the first to fourth days, expired gas was measured from a mask covering the mouth and nose using the breath-by-breath method (AE310S, Minato Medical Science Co., Ltd.) (Watanabe et al, 2014(Watanabe et al, , 2019. VO 2 relative to the body mass and the respiratory gas exchange ratio (RER) were calculated from the expired gas sampled for the final 1 min of 3-min exercises.…”

Effects of whole-body neuromuscular electrical stimulation device on hemodynamics, arrhythmia, and sublingual microcirculation

“…Several studies have used belt-electrode-type skeletal muscle electrical stimulation with electrodes attached to the torso, thighs, and lower legs to examine its effectiveness on circulatory dynamics, muscle contraction and hypertrophy, and safety in patients with arterial disease and diabetes mellitus [6][7][8][9]. Nowadays, there are novel and useful wearable devices for whole-body neuromuscular electrical stimulation (WB-NMES), rather than the traditional belt type, that efficiently provide electrical stimulation to the forearms and back arms, chest, back, abdomen, oblique abdomen, gluteus muscles, and front and back thigh muscles [10]. Watanabe et al [10] have shown that a combination of aerobic exercise and WB-NMES for 15 min enhances metabolic response to the same extent as high-intensity exercise.…”