title: Oxidation of combined ingestion of glucose and sucrose during exercise.
abstract: The first purpose of the study was to examine whether combined ingestion of glucose and sucrose at an intake rate of 1.2 g/min would lead to higher oxidation rates compared with the ingestion of an isocaloric amount of glucose or sucrose alone. The second aim of the study was to investigate whether a mixture of glucose and sucrose when ingested at a high rate (2.4 g/min) would result in exogenous CHO oxidation rates higher than 1.2 to 1.3 g/min. Eight trained cyclists (maximal oxygen consumption: 64 +/- 2 mL . kg -1 . min -1 , mean +/- SE) performed 5 exercise trials in random order. Each trial consisted of 120 minutes of cycling at 50% maximum power output (63% +/- 2% maximal oxygen consumption), whereas subjects received a solution providing either 1.2 g/min of glucose (GLU), 1.2 g/min of sucrose (SUC), 0.6 g/min of glucose + 0.6 g/min of sucrose (M-GLU+SUC), 1.2 g/min of glucose + 1.2 g/min of sucrose (H-GLU+SUC), or water (WAT). Peak exogenous CHO oxidation rates in the H-GLU+SUC trial (1.20 +/- 0.07 g/min) were significantly higher ( P < .01) compared with the GLU, M-GLU+SUC, and SUC trials (0.77 +/- 0.04, 0.90 +/- 0.07, 0.98 +/- 0.04 g/min, respectively). Furthermore, peak exogenous CHO rates in M-GLU+SUC and SUC trials were significantly higher ( P < .05) compared with the GLU trial. In conclusion, combined ingestion of moderate amounts of glucose and sucrose (144 g) during cycling exercise resulted in approximately 21% higher exogenous CHO oxidation rates compared with the ingestion of an isocaloric amount of glucose. Furthermore, when a mixture of glucose and sucrose was ingested at high rates (2.4 g/min), exogenous CHO oxidation rates reached peak values of approximately 1.20 g/min.
authors.affiliation: Human Performance Laboratory, School of Sport and Exercise Science, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Roy L P G
authors.initials: RL
authors.lastname: Jentjens
authors.forename: Christopher
authors.initials: C
authors.lastname: Shaw
authors.forename: Tom
authors.initials: T
authors.lastname: Birtles
authors.forename: Rosemary H
authors.initials: RH
authors.lastname: Waring
authors.forename: Leslie K
authors.initials: LK
authors.lastname: Harding
authors.forename: Asker E
authors.initials: AE
authors.lastname: Jeukendrup
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001769:Blood / Q000378:metabolism; D050260:Carbohydrate Metabolism; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D015444:Exercise / Q000502:physiology*; D005767:Gastrointestinal Diseases / Q000139:chemically induced; D005947:Glucose / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D012996:Solutions; D013395:Sucrose / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism*
chemical_list: D004338:Drug Combinations; D012996:Solutions; D013395:Sucrose; D005947:Glucose