Carbohydrate Oxidation from a Drink during Running Compared with Cycling Exercise
The purpose of this study was to investigate exogenous CHO oxidation from a CHO drink during moderate-intensity running (RUN) compared with cycling (CYCLE).Methods:
Eight athletes with comparable CYCLE and RUN training backgrounds (mean ± SD: age = 37 ± 7 yr, weight = 75 ± 7 kg, height = 1.77 ± 0.05 m; V˙O2max CYCLE = 63 ± 3 mL·kg−1·min−1, V˙O2max RUN = 65 ± 4 mL·kg−1·min−1) performed four exercise trials in random order. The trials consisted of either running or cycling at approximately 60% of the exercise specific V˙O2max for 120 min while receiving either a CHO drink (2:1 glucose-fructose blend; 1.5 g·min−1) or a similar volume of plain water (WAT; 675 mL·h−1).Results:
The set workload elicited similar relative exercise intensities of 59.7% ± 2.0% and 59.2% ± 1.9% V˙O2max for RUN and CYCLE, respectively. Peak and average exogenous CHO oxidation rates were not significantly different between RUN and CYCLE trials and showed a similar time course (peak at 120 min = 1.25 ± 0.10 vs 1.19 ± 0.08 g·min−1, respectively, P = 0.13; average over final hour = 1.14 ± 0.10 and 1.11 ± 0.11 g·min−1, respectively, P = 0.94). Furthermore, total fat oxidation rates were higher during RUN compared with CYCLE. The difference was significant with ingestion of WAT (P = 0.02) and failed to reach statistical significance with CHO (P = 0.09).Conclusions:
This study demonstrates that exogenous CHO oxidation rates are similar between prolonged running and cycling at a similar relative moderate intensity. These data suggest that previous exogenous CHO oxidation results from cycling studies can be extrapolated to running.