Adding protein to a carbohydrate pre-exercise beverage does not influence running performance and metabolism

摘要

BACKGROUND: To analyze whether pre-exercise CHO+PRO vs. CHO intake distinctly influences running performance and metabolic bio-markers along a various of exercise intensities.METHODS: In a randomized, double blind, counterbalanced, crossover and placebo control design, 10 middle distance runners were tested in 3 occasions. After 10 h of fasting, participants ingested isovolumic beverages (0.75+0.25gmiddotBW-1 of CHO+PRO, 1.0gmiddotBW-1 of CHO and placebo control) 30 min before a treadmill running incremental protocol of 4 min steps until exhaustion. Venous blood was collected at fasting, 30 min after beverage ingestion and after the 3rd and 7th running steps. Oxygen uptake-related variables, including respiratory exchange ratio, heart rate, plasma glucose, insulin, glucagon, free fatty acids, blood lactate concentrations, gastrointestinal discomfort and rate of perceived exertion were measured.RESULTS: The addition of PRO to CHO had no influence on the measured variables, which did not differ between conditions along all in-cremental protocol intensities. The intake of CHO+PRO (compared to CHO) tended to decrease glycemia (106.5 +/- 21.3 vs. 113.6 +/- 26.5) and to increase insulinemia (14.4 +/- 15.1 vs. 12.7 +/- 10.8) at intensities close to maximum oxygen uptake.CONCLUSIONS: The addition of PRO to a pre-exercise CHO beverage had no impact on running performance and related metabolic variables at a wide spectrum of exercise intensities.