Effects of carbohydrate intake on time to exhaustion and anaerobic contribution during supramaximal exercise

Abstract

Objective: This study evaluated the effect of carbohydrate intake on time to exhaustion and anaerobic contribution during supramaximal exercise on a cycle ergometer. Methods: The sample comprised ten participants with a mean age of 23.9±2.5 years, mean body mass of 75.1±12.3 kg, mean height of 170.0±1.0 cm, and mean body fat of 11.3±5.2%. The participants underwent an incremental test to determine maximal oxygen uptake and maximum power output, and two supramaximal tests with a constant load of 110% of the maximum power output to exhaustion. Thirty minutes before the supramaximal tests the participants consumed carbohydrates (2 g.kg-1) or placebo. Results: The times to exhaustion of carbohydrate and placebo did not differ (carbohydrate: 170.7±44.6s; placebo: 156.1±26.7s, p=0.17; effect size=0.39). Similarly, the anaerobic contributions of the two treatments did not differ (carbohydrate: 3.0±0.9 L; placebo: 2.7±1.1 L, p=0.23; effect size=0.29). Conclusion: Carbohydrate intake was not capable of increasing time to exhaustion and anaerobic contribution in physically active men cycling at 110% of maximum power output.

Carbohydrate mouth rinse reduces rating of perceived exertion but does not affect performance and energy systems contribution during a high-intensity exercise

“…Regarding the anaerobic contribution in high intensity exercise, studies verifying the effect of caffeine 24 and metformin 25 showed that even with a higher time to exhaustion, there was no significant difference in the anaerobic contribution in these exercises, probably because the anaerobic energy reserve may be a finite source 26 . On the other hand, as well as CHO mouth rinse, CHO intake did not increase time to exhaustion and anaerobic contribution in physically active cycling at 110% PPO 27 . Nevertheless, even without significant difference, time to exhaustion was 4.4% longer in CHO than in PLA, and was associated with a lower RPE, possibly because CHO mouth rinse may have activated brain regions (including areas of the insula/frontal operculum, orbitofrontal cortex and striatum) involved in reward 8,9 .…”