Preexercise breakfast ingestion versus extended overnight fasting increases postprandial glucose flux after exercise in healthy men

Edinburgh, R.M.; Hengist, A.; Smith, H.A.; Travers, R.L.; Koumanov, F.; Betts, J.A.; Thompson, D.; Walhin, J.-P.; Wallis, G.A.; Hamilton, D.L.; Stevenson, E.J.; Tipton, K.D.; Gonzalez, J.T.

Abstract

The aim of this study was to characterize postprandial glucose flux after exercise in the fed versus overnight fasted state and to investigate the potential underlying mechanisms. In a randomized order, twelve men underwent breakfast-rest [(BR) 3 h semirecumbent], breakfast-exercise [(BE) 2 h semirecumbent before 60 min of cycling (50% peak power output)], and overnight fasted exercise [(FE) as per BE omitting breakfast] trials. An oral glucose tolerance test (OGTT) was completed after exercise (after rest on BR). Dual stable isotope tracers ([U-13C] glucose ingestion and [6,6-2H2] glucose infusion) and muscle biopsies were combined to assess postprandial plasma glucose kinetics and intramuscular signaling, respectively. Plasma intestinal fatty acid binding (I-FABP) concentrations were determined as a marker of intestinal damage. Breakfast before exercise increased postexercise plasma glucose disposal rates during the OGTT, from 44 g/120 min in FE {35 to 53 g/120 min [mean (normalized 95% confidence interval)] to 73 g/120 min in BE [55 to 90 g/120 min; P = 0.01]}. This higher plasma glucose disposal rate was, however, offset by increased plasma glucose appearance rates (principally OGTT-derived), resulting in a glycemic response that did not differ between BE and FE (P = 0.11). Plasma I-FABP concentrations during exercise were 264 pg/ml (196 to 332 pg/ml) lower in BE versus FE (P = 0.01). Breakfast before exercise increases postexercise postprandial plasma glucose disposal, which is offset (primarily) by increased appearance rates of orally ingested glucose. Therefore, metabolic responses to fed-state exercise cannot be readily inferred from studies conducted in a fasted state.

Citation

Edinburgh, R., Hengist, A., Smith, H., Travers, R., Koumanov, F., Betts, J., Thompson, D., Walhin, J.-P., Wallis, G., Hamilton, D., Stevenson, E., Tipton, K., & Gonzalez, J. (2018). Preexercise breakfast ingestion versus extended overnight fasting increases postprandial glucose flux after exercise in healthy men. AJP - Endocrinology and Metabolism, 315(5), E1062-E1074. https://doi.org/10.1152/ajpendo.00163.2018

• Journal Article Type: Article
• Acceptance Date: Aug 2, 2018
• Online Publication Date: Nov 9, 2018
• Publication Date: Nov 30, 2018
• Deposit Date: Jun 15, 2019
• Publicly Available Date: Nov 21, 2019
• Journal: AJP - Endocrinology and Metabolism
• Print ISSN: 0193-1849
• Electronic ISSN: 1522-1555
• Publisher: American Physiological Society
• Peer Reviewed: Peer Reviewed
• Volume: 315
• Issue: 5
• Pages: E1062-E1074
• DOI: https://doi.org/10.1152/ajpendo.00163.2018
• Public URL: https://durham-repository.worktribe.com/output/1328764