How eating carbohydrates affects metabolism during running and cycling

Plasma glucose oxidation was greater with carbohydrate ingestion than with water during both running (65 ± 20 vs. 42 ± 16 g/h) and cycling (57 ± 16 vs. 35 ± 12 g/h).

• Carbohydrate ingestion increased the contribution of plasma glucose oxidation to total carbohydrate oxidation during both running and cycling.
• During running, plasma glucose oxidation accounted for 33 ± 4% with carbohydrate compared to 23 ± 3% with water.
• During cycling, plasma glucose oxidation represented 36 ± 5% with carbohydrate compared to 22 ± 3% with water.
• Muscle glycogen utilization was not significantly different with carbohydrate compared to water during either activity.
• For running, muscle glycogen utilization was 112 ± 32 mmol/kg dry mass with carbohydrate versus 141 ± 34 mmol/kg dry mass with water.
• For cycling, muscle glycogen utilization was 227 ± 36 mmol/kg dry mass with carbohydrate compared to 216 ± 39 mmol/kg dry mass with water.

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