Abstract

Aim of the study is to determine whether consuming lactate added to a carbohydrate-electrolyte beverage would result in enhanced exercise performance. 9 subjects completed 3 separate sessions; each consisting of 60 min of cycling at 65% VO2max, including three 2-min bouts at 85% VO2max at min 15, 30, and 45. A performance test consisting of cycling 4 miles for time was performed following 60 min of cycling. Each subject consumed 2.9 ml/kg/BW of either water placebo (WP), or solutions of 6% carbohydrate comprised of 4% sucrose, 2% glucose with electrolytes (20 mmol/l Na+, 3 mmol/l K+) (SG), or 4% sucrose, 2% lactate with electrolytes (20 mmol/l Na+, 3 mmol/l K+) (SL), and amino acids (arginine 1.6%, glycine 1.0% and glutamine 0.6%). All beverages were administered in a double blind counterbalance order. Mean times for the performance test were: WP=626.3+-32.8 sec, SG=600.5+-33.6 and SL=650.5+-48.6 sec. There were no significant differences in blood pH, pCO2 or HCO3 at any time point during the exercise bouts. Plasma lactate concentrations were significantly elevated during exercise and following the post-exercise performance test, but were not changed by treatment. Compared to WP, ingestion of SG and SL resulted in significantly higher plasma glucose concentrations during exercise. In addition, ingestion of SG resulted in significantly higher glucose concentrations than when consuming SL. Results indicate that the substitution of 2% lactate for 2% glucose in a 6% carbohydrate-electrolyte drink does not improve performance. Verf.-Ref.