Natalie Zm Eichner

Combining Short-Term Interval Training with Caloric Restriction Improves ß-Cell Function in Obese Adults

Although low-calorie diets (LCD) improve glucose regulation, it is unclear if interval exercise (INT) is additive. We examined the impact of an LCD versus LCD + INT training on ß-cell function in relation to glucose tolerance in obese adults. Twenty-six adults (Age: 46 ± 12 year; BMI 38 ± 6 kg/m2) were randomized to 2-week of LCD (~1200 kcal/day) or energy-matched LCD + INT (60 min/day alternating 3 min at 90 and 50% HRpeak). A 2 h 75 g oral glucose tolerance test (OGTT) was performed. Insulin secretion rates (ISR) were determined by deconvolution modeling to assess glucose-stimulated insulin secretion ([GSIS: ISR/glucose total area under the curve (tAUC)]) and ß-cell function (Disposition Index [DI: GSIS/IR]) relative to skeletal muscle (Matsuda Index), hepatic (HOMA-IR) and adipose (Adipose-IRfasting) insulin resistance (IR). LCD + INT, but not LCD alone, reduced glucose and total-phase ISR tAUC (Interactions: p = 0.04 and p = 0.05, respectively). Both interventions improved skeletal muscle IR by 16% (p = 0.04) and skeletal muscle and hepatic DI (Time: p < 0.05). Improved skeletal muscle DI was associated with lower glucose tAUC (r = −0.57, p < 0.01). Thus, LCD + INT improved glucose tolerance more than LCD in obese adults, and these findings relate to ß-cell function. These data support LCD + INT for preserving pancreatic function for type 2 diabetes prevention.

Short-Term Interval and Continuous Training Improves Pancreatic ß-Cell Function Adjusted for Skeletal Muscle Insulin Resistance in Adults with Prediabetes

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