Title: Effect of Carbohydrate Supplementation Type on Endurance Cycling Performance in Competitive Athletes
Abstract: PURPOSE: To determine the effect of carbohydrate supplementation type on endurance cycling performance. METHODS: On four separate days, eight male (35.8 ± 2.5 yrs) and eight female (32.4 ± 2.4 yrs) athletes cycled at 75% VO2peak for 80 min followed by a 10 kilometer time trial. Subjects consumed isocaloric (CHO)(5.9% or 0.6 grams of CHO per kg, per hour) amounts of randomly assigned sport beans (SB), drink (SD), gel or water only, before, during and after exercise. Fluid intake (7 ml/kg before and after and 3.5 ml/kg every 20 min during exercise) was kept constant for all trials. Heart rate (HR), rate of perceived exertion (RPE), respiratory exchange ratio (RER) and blood glucose, lactate, electrolyte and free fatty acid (FFA) concentrations were collected before, during, and following exercise. RESULTS: There were no differences in HR, RPE, RER or blood lactate responses between treatments during the 80 min exercise bout. Blood glucose concentrations were similar at rest between treatments and decreased significantly during exercise with the water trial only. Blood glucose concentrations for all CHO supplements were significantly, p < 0.05, higher than water during the 80 min exercise bout and during the time trial (99.8 ± 5.3 mg/dl for SB, 98.6 ± 5.4 mg/dl for SD, 105.1 ± 8.1 mg/dl for Gel and 79.6 ± 5.1 mg/dl for water). There were no significant differences between CHO treatments. All 3 CHO treatments had significantly faster 10K time trials (17.18 ± 0.6 min for SB, 17.25 ± 0.6 min for SD, 17.28 ± 0.6 min for Gel) versus water (17.82 ± 0.7 min). Only the SB trial had higher average power outputs during the 10K time trial (226.3 ± 17.7 watts) vs. water (208.1 ± 18.2 watts). HR, VO2, RER, and blood glucose and lactate levels were higher with all CHO supplements versus water immediately following the 10K time trial. CONCLUSIONS: All carbohydrate supplementation types (sports beans, drinks or gel) were equally effective in maintaining blood glucose levels during exercise and improving exercise performance compared to water only. Sponsored by a grant from the Jelly Belly Candy Company