Exercise improves pancreatic function in an energy dose-dependent manner. We previously showed that when calories are matched, an acute exercise bout changes glucose-stimulated insulin secretion (GSIS) relative to multi-organ insulin resistance (IR) in an intensity-based manner during the immediate post-exercise period in people with prediabetes. However, the impact of short-term training intensity on ß-cell function is unknown. Thus, we examined the impact of high-intensity interval and moderate-continuous training on GSIS relative to multi-organ IR in adults with prediabetes. Thirty-one adults (Age: 61±8y; BMI: 33±6 kg/m2) with prediabetes according to ADA 75g OGTT and/or HbA1c criteria were randomized to energy-matched interval (INT: 60-min/d alternating 3-min at 90 and 50% HRpeak) or continuous training (CONT: 60-min/d 70% HRpeak) for 2 weeks. Fitness (VO2peak) and body mass were measured before and after, and a 120-min 75g OGTT with blood samples for glucose, insulin, C-peptide and FFA were determined every 30-min. GSIS (C-pep/Glc tAUC0-120min) and ß-cell function (Disposition Index [DI: GSIS/IR]) relative to skeletal muscle (InsulintAUC x GlctAUC), hepatic (HOMA-IR) and adipose (Adipose-IRfasting) IR were calculated. Training increased VO2peak (+1.1±2.1 mL/kg/min), and reduced body mass (-0.6±1.1 kg) and IR (-11±31%), independent of intensity (P<0.05). INT and CONT also decreased GSIS to a similar extent (Interaction: P=0.88). Short-term training improved skeletal muscle DI by ∼24% (P<0.05), but there was no effect on hepatic or adipose DI. Collectively, short-term INT and CONT training improves ß-cell function relative to skeletal muscle, but not hepatic or adipose, IR. These data suggest unique mechanisms regulate glucose metabolism following single vs. habitual physical activity in adults with prediabetes.


M.E. Francois: None. N. Eichner: None. N.M. Gilbertson: None. E.M. Heiston: None. E. Barrett: None. S.K. Malin: None.

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