Carbohydrate drinks and cycling performance.

Abstract

We compared the effects of similarly tasting orange flavored drinks containing 0% (P), 6.4% (E1), and 10% (E2) carbohydrate (CHO) using 12 well-trained cyclists (VO2max = 5.0 l/min-1) on metabolic responses to exercise (EX) and a sprint type performance ride (PR). Each subject completed 3 separate 2 h EX bouts at 65% VO2max followed by a PR identified as the time in sec to complete 500 revolutions at a constant belt resistance of 29.4 N (ANOVA*). The CHO feedings or placebo of 3 ml/kg body weight were given double blind and counter-balanced at 0 min and every 20 min thereafter during EX. Blood samples were drawn and core temperature (Tr) was recorded at 0, 30, 60, 90, and 120 min of EX and 1 min post PR. Blood samples were analyzed for glucose (G) and lactate [LA-]. Blood G at 0 min were similar; however, at 120 min, G was 3.96 mM for P*, 4.57 mM for E1, and 4.77 mM for E2. Blood [LA-] remained similar throughout EX averaging (P, 2.6 mM; E1, 2.9 mM; E2, 2.5 mM). Tr at 120 min was also similar (P, 38.5 degrees C; E1, 38.6 degrees C; E2, 38.3 degrees C). Mean PR times for P(264.4 s)**, E1 (255.3 s)*, E2 (252.4 s)* indicate consumption of a CHO drink during EX improves PR. Furthermore, a 10% CHO drink improves PR more than a 6.4% CHO drink.