One Bout of Resistance Training Does Not Enhance Metformin Actions in Prediabetic and Diabetic Individuals
Alfonso Moreno‐Cabañas, Juan F. Ortega, Felix Morales‐Palomo, Miguel Ramírez-Jiménez, Laura Álvarez-Jiménez, Ricardo Mora‐Rodríguez
Abstract
PURPOSE: This study aimed to determine the separated and combined effects of metformin and resistance exercise on glycemic control, insulin sensitivity, and insulin-like growth factor 1 (IGF-1) in overweight/obese individuals with prediabetes and type 2 diabetes mellitus. METHODS: Fourteen adults with a body mass index of 32.1 ± 4.1 kg·m-2, insulin resistance (HOMA-2 1.6 ± 0.6), and poor glycemic control (glycated hemoglobin, 6.9% ± 0.9%; 51.9 ± 10.7 mmol·mol-1) while taking metformin (1561 ± 470 g·d-1) were recruited. Participants underwent four 72-h long experimental trials in a randomized counterbalanced order, either 1) taking metformin (MET), 2) replacing metformin by placebo pills (PLAC), 3) taking placebo and undergoing a resistance training bout (RT + PLAC), and 4) taking metformin and undergoing the same RT bout (RT + MET). Interstitial fluid glucose concentration was frequently sampled to obtain 72-h glucose area under the curve (GAUC) and the percentage hyperglycemic glucose readings (>180 mg·dL-1; GPEAKS). Insulin sensitivity (i.e., HOMA-2) and IGF-1 were also assessed. RESULTS: HOMA-2 was not affected by treatments. GAUC and GPEAKS were similarly reduced below PLAC during RT + MET and MET (all P < 0.05). In contrast, RT + PLAC did not affect glucose concentration. Metformin decreased serum IGF-1 concentrations (P = 0.006), and RT did not reverse this reduction. CONCLUSIONS: A bout of full-body RT does not interfere or aid on metformin's blood glucose-lowering actions in individuals with prediabetes and type 2 diabetes mellitus.