Introduction/Purpose: Most U.S. adults (54%) do not meet minimum exercise recommendations by American College of Sports Medicine (ACSM). Neuromuscular electrical stimulation (NMES) is a novel alternate strategy to induce muscle contraction. However, effectiveness of NMES to improve insulin sensitivity and energy expenditure is unclear. The purpose of this study was to investigate the effects of four weeks of NMES on glucose tolerance in a sedentary overweight or obese population. Methods: Participants (n=10; age: 36.8 ± 3.8 years; BMI=32 ± 1.3 kg/ m2) were randomized into either control or NMES group. All participants received bilateral quadriceps stimulation (12 sessions; 30 minutes/session; 3 times/week at 50 Hz and 300 µs pulse width) altering pulse amplitude to either provide low intensity sensory level (control; tingling sensation) or at high intensity neuromuscular level (NMES; maximum tolerable levels with visible muscle contraction). Glucose tolerance was assessed by three-hour oral glucose tolerance test (OGTT), substrate utilization was measured by indirect calorimetry and body composition via dual X-ray absorptiometry at baseline and after four weeks of NMES intervention. Results: Control and NMES groups had comparable fasting blood glucose, glucose tolerance, substrate utilization, and muscle mass at baseline. Four weeks of NMES resulted in a significant improvement in glucose tolerance measured by OGTT, whereas no change was observed in control group. There was no change in substrate utilization and in muscle mass in both control and NMES groups. Conclusion: NMES is a novel and effective strategy to improve glucose tolerance in an at-risk overweight or obese sedentary population.

No abstract

Most U.S. adults do not meet minimum exercise recommendations by ACSM. We and others have shown an increase in GLUT4 protein and glucose uptake with electrical stimulation induced muscle contraction using an in vitro cell culture model. However, effectiveness of neuromuscular electrical stimulation (NMES) in humans to improve insulin sensitivity is not clear. Purpose: To determine the effects of four weeks of NMES on insulin sensitivity, substrate utilization, and muscle mass in sedentary humans. Methods: Sedentary overweight/obese subjects (n=10; Age 36.8 ±3.8 yrs; BMI 32.0 ±1.3 kg/m2) were randomized into a control (Con) or NMES group. All participants received bilateral quadriceps stimulation (3x/wk; 30 min/ses) either at low intensity sensory level (Con) or high intensity neuromuscular level (NMES) for 4 weeks (50Hz). Insulin sensitivity was assessed by oral glucose tolerance test (OGTT), substrate utilization by indirect calorimetry, blood lactate by lactate analyzer, and body composition by DXA. Results: Con and NMES groups had comparable fasting blood glucose, glucose tolerance, substrate utilization, and muscle mass (all p>0.05) at baseline. Four weeks of NMES tended to improve glucose tolerance, measured by glucose area under the curve (AUC) (455.6 ±26.1 to 415.4 ±25.9 AU; p=0.07) whereas no change was observed in Con (430.7 ±20.2 to 494.7 ±77.2 AU; p=0.76). Glucose level after 2 hours of glucose consumption during OGTT was significantly lower after 4 weeks of NMES (150.9 ±7.6 to 138.2 ±7.6 mg/dL; p=0.03) whereas no change was observed in Con (151.8 ±6.1 to 173.2 ±34.2 mg/dL; p=0.33).Additionally, lactate AUC assessed during 30 min of NMES, was significantly greater compared to that of Con (p<0.02). There was no change in substrate utilization (p=0.85) or muscle mass (p=0.17) after NMES intervention. Conclusion: NMES is a novel and effective strategy to improve insulin sensitivity and glucose utilization in an at-risk overweight/obese sedentary population. Disclosure S. Bajpeyi: None. M. Galvan: None. M.J. Sanchez: None. J.B. Boyle: None. K. Min: None. F.J. Agullo: None. J.D. Covington: None. Funding University of Texas at El Paso