Effects of Whole Body Vibration Plus Diet on Insulin-Resistance in Middle-Aged Obese Subjects

We investigated the early effects of whole body vibration (WBV) added to hypocaloric diet on insulin-resistance and other parameters associated with glucose regulation in sedentary obese individuals. We randomly assigned 34 patients to WBV plus hypocaloric diet (WBV group) or diet alone (CON group) for 8 weeks. Fasting and post-load glucose, insulin, lipids, C-reactive protein, tumor necrosis factor-alpha, leptin, adiponectin were assessed. Insulin sensitivity index (ISI) was derived from oral-glucose-tolerance test. Body composition was evaluated with dual-energy X-ray absorptiometry. Both groups lost approximately 5% of weight, with greater reduction of body fat in WBV than in CON (-7.1 +/- 1.2 Kg vs. -5.3 +/- 1.0 Kg, p = 0.003). Percent variation of ISI was more pronounced in WBV than in CON group (+35 +/- 4% vs. +22 +/- 5%, p = 0.002), accompanied by slight improvement in post-load glucose (-1.07 +/- 0.02 vs. -0.12 +/- 0.01 mmol/l, p = 0.031) but without changes in fasting levels. Adiponectin significantly increased in WBV group compared with CON (p = 0.021 for comparison) whereas no differences in leptin and inflammatory markers were observed. In middle-aged sedentary obese subjects, WBV added to hypocaloric diet for 8 weeks improved body composition, insulin-resistance, glucose regulation and adiponectin levels to a greater extent compared with diet alone. Efficacy and feasibility of this approach in the long term need to be ascertained.