Electrical Muscle Stimulation With or Without Blood Flow Restriction Does Not Prevent the Impairment in Glycemic...

Physical inactivity depresses glycemic control, an impairment that can be prevented with exercise. We investigated whether electrical muscle stimulation (EMS) with blood flow restriction (BFR) could similarly prevent the impairments in glycemic control associated with physical inactivity and whether this was effective for attenuating the loss of physical function after inactivity. Thirty-two participants underwent 1 week of step reduction (≤ 3000 steps/day) randomized to either no intervention (Control), twice daily EMS, or twice daily EMS with BFR (EMS + BFR). Oral glucose tolerance and tests of physical function (neuromuscular function, and cardiorespiratory fitness) were assessed before and after step reduction. Blood glucose incremental area under the curve (iAUC) during the oral glucose tolerance test increased after step reduction (Control: ∆71 ± 133 mM⋅min, EMS: ∆56 ± 65 mM⋅min, EMS + BFR: ∆103 ± 78 mM⋅min, p = 0.0002), as was the insulin iAUC (Control: ∆3580 ± 3245μIU⋅min/mL, EMS: ∆2266 ± 5043μIU⋅min/mL, EMS + BFR: ∆1534 ± 1246μIU⋅min/mL, p = 0.001). A relationship between the change in blood glucose and insulin response was observed after Control (r² = 0.71, p = 0.002), but not after EMS + BFR (r² < 0.01, p = 0.93), despite all groups demonstrating a reduction in whole-body insulin sensitivity (Matsuda index; Control: ∆-1.4 ± 2.5, EMS: ∆-1.3 ± 1.5, EMS + BFR: ∆-1.5 ± 1.5, p < 0.0001). Maximal oxygen uptake was not reduced after 1 week of inactivity; however, maximal isometric force production and exercise thresholds were reduced across groups. In summary, EMS + BFR did not prevent the decrease in insulin sensitivity nor attenuate measurements of physical function with 1 week of physical inactivity. The relevance of the dissociated insulin and glucose response with EMS + BFR remains to be determined.