Sub-maximal oxidation trial Following a 10 minute warm up at 100 W, participants began a 2.5 hour oxidation trial at 50% Wmax. Steady state power output was based on individual quantification of Wmax from pre-experimental assessment.

Expired air samples were collected via the Douglas bag method at 30 and 60 minutes, and then 15 minute intervals thereafter, and analysed for percentage AZD2014 O2 and CO2, using a Servomex 1440 gas analyser (Servomex Group Ltd, Crowborough, UK). Total Douglas bag volume was measured using a dry gas meter (Harvard Apparatus, Holliston, USA). Standardised measurements for minute ventilation (VE, L.min-1), oxygen uptake (VO2, L.min-1), carbon dioxide (VCO2, L.min-1) and respiratory exchange ratio (RER) were recorded at 0, 30 and 60 minutes, and every 15 minutes thereafter during the oxidation trial. In addition, immediately following each Douglas bag collection, duplicate 10 ml expired air samples were extracted

into vacuumed Exetainer tubes (Labco Ltd, High Wycombe, UK) for the determination of expired gas 13C:12C ratio. Exetainer samples were analysed independently (Iso-Analytical Ltd., Crewe, UK) for 13C:12C ratio by gas chromatography continuous flow isotope ratio mass spectrometry (GC-IRMS, Europa Scientific 20–20 IRMS). Stable isotope measurements and indirect calorimetry HSP inhibitor were used to calculate rates of CHOEXO, CHOTOT (total carbohydrate oxidation) and FATTOT (total fat oxidation). At rest, and at 15 minute intervals throughout the oxidation trial, 30 μl of capillarised wholeblood was collected in heparinised tubes and frozen at -8°C for subsequent analysis of blood glucose using an Analox micro-stat PGM7 (Analox Instruments Ltd, London, UK). Telemetric HR was recorded at 15 minute intervals throughout the oxidation trial. Ratings of perceived exertion (RPETOTAL and RPELEGS) using the 6–20 and 0–10 Borg scales respectively were recorded every

30 minutes during submaximal exercise. Participants also verbally completed an adapted 14 point gastrointestinal (GI) symptom assessment questionnaire [31] every 30 minutes, grading the degree of subjective discomfort on a 0–10 visual analogue scale. Particular attention was given to symptoms categorised Beta adrenergic receptor kinase as both ‘moderate’ (4–6) and ‘severe’ (7–10). Beverage administration In a double-blind random order manner, participants were assigned the following beverages across trials: maltodextrin only (MD), isoenergetic maltodextrin with fructose (MD + F) or aspartame sweetened, citrus flavoured water (P). All CHO beverages were supplied by High 5 Ltd., and prepared as 10% concentrated formulas in opaque drinks bottles. The test beverages provided an average CHO delivery rate of 1.7 g · min-1 for MD (corn-derived glucose monohydrate), and 1.1 g · min-1 maltodextrin with 0.6 g · min-1 fructose for MD + F (using corn-derived glucose monohydrate and crystalline fructose, Energy Source™, High 5 Ltd.).