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.
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Accepted: December 1, 2004
Received: March 8, 2004
☆This study was supported by a grant from GlaxoSmithKline Consumer Healthcare, United Kingdom.
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