title: The immediate effects of a single bout of aerobic exercise on oral glucose tolerance across the glucose tolerance continuum.
abstract: We investigated glucose tolerance and postprandial glucose fluxes immediately after a single bout of aerobic exercise in subjects representing the entire glucose tolerance continuum. Twenty-four men with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or type 2 diabetes (T2D; age: 56 ± 1 years; body mass index: 27.8 ± 0.7 kg/m(2), P > 0.05) underwent a 180-min oral glucose tolerance test (OGTT) combined with constant intravenous infusion of [6,6-(2)H2]glucose and ingestion of [U-(13)C]glucose, following 1 h of exercise (50% of peak aerobic power) or rest. In both trials, plasma glucose concentrations and kinetics, insulin, C-peptide, and glucagon were measured. Rates (mg kg(-1) min(-1)) of glucose appearance from endogenous (RaEndo) and exogenous (oral glucose; Ra OGTT) sources, and glucose disappearance (Rd) were determined. We found that exercise increased RaEndo, RaOGTT, and Rd (all P < 0.0001) in all groups with a tendency for a greater (~20%) peak RaOGTT value in NGT subjects when compared to IGT and T2D subjects. Accordingly, following exercise, the plasma glucose concentration during the OGTT was increased in NGT subjects (P < 0.05), while unchanged in subjects with IGT and T2D. In conclusion, while a single bout of moderate-intensity exercise increased the postprandial glucose response in NGT subjects, glucose tolerance following exercise was preserved in the two hyperglycemic groups. Thus, postprandial plasma glucose responses immediately following exercise are dependent on the underlying degree of glycemic control.
authors.affiliation: Department of Infectious Diseases, The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Sine H
authors.initials: SH
authors.lastname: Knudsen
authors.affiliation: Department of Infectious Diseases, The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Karstoft
authors.affiliation: Department of Infectious Diseases, The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Bente K
authors.initials: BK
authors.lastname: Pedersen
authors.affiliation: Clinical Metabolomics Core Facility, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Gerrit
authors.initials: G
authors.lastname: van Hall
authors.affiliation: Department of Infectious Diseases, The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thomas P J
authors.initials: TP
authors.lastname: Solomon
keywords: Glucose kinetics; oral glucose tolerance test; physical activity; type 2 diabetes