Impact of Short-Term Exercise Training Intensity on β-cell Function in Older Obese Adults with Prediabetes

The effect of work-matched exercise intensity on β-cell function is unknown in people with prediabetes prior to clinical weight loss. We determined if short-term moderate continuous (CONT) versus high intensity interval (INT) exercise increased β-cell function. Thirty-one subjects (Age: 61.4±2.5 yr; BMI: 32.1±1.0 kg/m2) with prediabetes (ADA criteria, 75g OGTT) were randomized to work-matched CONT (70% HRpeak) or INT (3 min 90% HRpeak and 3 min 50% HRpeak) exercise for 60min/d over 2-weeks. A 75g 2 hr OGTT was conducted after an overnight fast, and plasma glucose, insulin, C-peptide and FFA were determined for calculations of skeletal muscle (Oral Minimal Model; OMM), hepatic (HOMA-IR), and adipose (Adipose-IR) insulin sensitivity. β-cell function was defined from glucose-stimulated insulin secretion (GSIS, deconvolution modeling) and the disposition index (DI). GLP-1(active) and GIP were also measured during the OGTT, along with VO2peak and body composition. CONT and INT increased skeletal muscle, but no...