Pfeiffer, B., Stellingwerff, T., Zaltas, E., & Jeukendrup, A. (2010). Carbohydrate oxidation from a drink during running compared to cycling exercise. Presentation 859 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

This study investigated the commonalities and differences in exogenous carbohydrate oxidation after a carbohydrate drink in two activities, running and cycling. Well-trained cyclists (N = 8) performed four exercise trials in random order. The trials consisted of either running or cycling for 120 minutes at ~60% of Ss' sport-specific VO2max while receiving either a carbohydrate drink, delivering 1.5 g CHO/min, or a similar volume of plain water.

Exogenous carbohydrate oxidation from both treatments showed a similar time course. Peak exogenous carbohydrate oxidation rates were reached at the end of 120 minutes of exercise and were not significantly different between the two forms of exercise. Average exogenous carbohydrate oxidation over the final hour of exercise was not significantly different between treatments. Oxidation efficiency was not significantly different between running and cycling trials. Average heart rate over the last hour was ~4 bpm higher during running compared to cycling. However, rating of perceived exertion values were similar between all trials and treatments.

Implication. A carbohydrate drink is oxidized as effectively during running as in cycling at a similar relative intensity (~60% VO2max). The implications of research involving carbohydrate intake derived from cycling studies can be extrapolated to running and vice versa.

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