caa a22 4500 469055138 CHVBK 20180323132841.0 cr unu---uuuuu 170328e19921101xx s 000 0 eng 10.1007/BF00843762 doi (NATIONALLICENCE)springer-10.1007/BF00843762 Exogenous carbohydrate oxidation from maltose and glucose ingested during prolonged exercise [Elektronische Daten] [John Hawley, Steven Dennis, Andrea Nowitz, Fred Brouns, Timothy Noakes] Summary: Intestinal perfusion studies have shown that glucose absorption from maltose occurs faster than from isocaloric glucose. To determine whether ingested maltose might be a superior source of carbohydrate (CHO) for endurance athletes, we compared the rates of gastric emptying, absorption and oxidation of 15 g · 100 ml−1 solutions of maltose and glucose. Six endurance-trained cyclists drank 1200 ml of either U-14C maltose or U-14C glucose as a 400-ml loading bolus immediately before exercise, and as 8 × 100-ml drinks at 10-min intervals during a 90-min ride at 700% of maximal oxygen consumption. The rates of gastric emptying [maltose 690 (SD 119) ml · 90 min−1; glucose 655 (SD 93) ml · 90 min−1], the appearance of U-14C label in the plasma, and the peak rates of exogenous CHO oxidation [maltose 1.0 (SD 0.09) g · min−1; glucose 0.9 (SD 0.09) g · min−1] were not significantly different. Further, the 51 (SD 8) g of maltose and the 49 (SD 9) g of glucose oxidised during exercise were similar. Each accounted for approximately 2001o of the total CHO oxidised during the 90 min of exercise. Since only half of the CHO delivered to the intestine was oxidised in the 90-min ride (maltose 49%; glucose 50%), we conclude that neither the rate of gastric emptying, nor digestion limited the rate of ingested CHO utilisation during the early stages of exercise. Rather, we hypothesise that, initially, it could be the rate at which the CHO diffuses across the unstirred water layer of the brush-border of the intestinal villi that limits the utilisation of soluble CHO ingested during prolonged exercise. Springer-Verlag, 1992 Gastric emptying nationallicence U-14C maltose nationallicence Prolonged exercise nationallicence Hawley John The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut Dennis Steven The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut Nowitz Andrea The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut Brouns Fred Wander Research Laboratories, 3176, Bern, Switzerland aut Noakes Timothy The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut European Journal of Applied Physiology and Occupational Physiology Springer-Verlag 64/6(1992-11-01), 523-527 0301-5548 64:6<523 1992 64 421 https://doi.org/10.1007/BF00843762 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00843762 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hawley John The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut NATIONALLICENCE 700 1- Dennis Steven The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut NATIONALLICENCE 700 1- Nowitz Andrea The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut NATIONALLICENCE 700 1- Brouns Fred Wander Research Laboratories, 3176, Bern, Switzerland aut NATIONALLICENCE 700 1- Noakes Timothy The Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, South Africa aut NATIONALLICENCE 773 0- European Journal of Applied Physiology and Occupational Physiology Springer-Verlag 64/6(1992-11-01), 523-527 0301-5548 64:6<523 1992 64 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer