Int J Sports Med 1994; 15(7): 430-434
DOI: 10.1055/s-2007-1021083

© Georg Thieme Verlag Stuttgart · New York

Adding Polylactate to a Glucose Polymer Solution Does Not Improve Endurance

T. Swensen, G. Crater, D. R. Bassett Jr., E. T. Howley
  • Departments of Zoology and Human Performance and Sports Studies, University of Tennessee, Knoxville TN 37996
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14. März 2008 (online)


Polylactate (PL), a semi-soluble amino acid /lactate salt, is a newly developed carbohydrate supplement purported to increase endurance. Our purpose was to determine if the addition of PL to a glucose polymer solution (GP) extends exercise time relative to a pure GP solution. In a double blind and random crossover design, 5 subjects exercised twice to exhaustion at 70% of V̇O2max. During the trials, they consumed GP or a GP/PL mixture at the rate of 0.3 g carbohydrate per kg of body wt in a 7% solution every 20min until exhaustion. The GP/PL mixture contained 6.25 g GP to 0.75 g PL per 100 ml of water. Mixture composition was critical because PL, as supplied by the manufacturer and under our experimental conditions, produced severe gastro-intestinal efflux in concentrations ≥ 2.5%; PL was tolerable in concentrations ≤ 0.75%. At 20 min intervals, we measured V̇O2, respiratory exchange ratio, heart rate, and perceived exertion. At 30 min intervals, we measured serum glucose, insulin, free fatty acids, and glycerol as well as whole blood lactate and pH. We found that the addition of PL to a GP solution had no measurable physiological or performance effects.