Novel Approach for Glycemic Management Incorporating Vibration Stimulation of Skeletal Muscle in Obesity

Abstract

Because obesity is associated with impaired glucose tolerance and type 2 diabetes (T2D), it is important to manage the blood glucose level at an early stage. Nevertheless, people with obesity have significantly lower resistance to muscle fatigue after exercise and exercise adherence. Therefore, we developed a novel "Relaxing-Vibration Training (_RVT)" consisting of 25 postures using vibration stimulation of skeletal muscle and determined the feasibility of _RVT for glycemic management. Thirty-one participants with obesity were enrolled in a controlled trial (CT) and experimental trial (ET) based on a 75 g oral glucose tolerance test (OGTT). During the CT, participants were required to rest in a quiet room. During the ET, the _RVT program (50 Hz, 4 mm), consisting of 25 postures of relaxation and stretching on the vibratory platform, was performed for 40 min. Subsequently, the participants rested as in the CT. Subjective fatigue and muscle stiffness measurements and blood collection were conducted before and after _RVT. In both the CT and ET, interstitial fluid (ISF) glucose concentrations were measured every 15 min for 2 h. The incremental area under the curve value of real-time ISF glucose during an OGTT was significantly lower in the ET than in the CT (ET: 7476.5 ± 2974.9, CT: 8078.5 ± 3077.7, effect size r = 0.4). Additionally, the levels of metabolic glucose regulators associated with myokines, muscle stiffness, and subjective fatigue significantly improved after _RVT. This novel _RVT suggests that it is effective in glycemic management with great potential to improve impaired glucose tolerance and T2D with obesity in the future.

Keywords: impaired glucose tolerance; muscle stiffness; myokine; obesity; vibration therapy.

Figure 1

Schematic illustrating the experimental protocol and time course of the study in (A) the CT and (B) the ET.

Figure 2

Flow diagram for the study.

Figure 3

Comparison of (A) ISF glucose concentrations and (B) the IAUC in the CT and the ET. Data are expressed using (A) the linear mixed model (mean ± SE) and (B) the Wilcoxon signed-rank test (median, min, max), * p < 0.05. Abbreviations: CT: controlled trial, ET: experimental intervention trial, ISF: interstitial fluid, IAUC: incremental area under the curve, SE: standard error.

Figure 4

Changes in the levels of markers of metabolic regulation of glucose and lipid after _RVT: cortisol, FGF21, myostatin, IL-6, and FFAs. Data are expressed using the Wilcoxon signed-rank test (median, min, max). Abbreviations: FGF21: fibroblast growth factor 21, IL6: interleukin 6, FFA: free fatty acid.