Efeito do tipo de carboidrato no desempenho e no desconforto gastrointestinal induzido pelo exercício

Abstract

Introduction: It is well established that carbohydrate consumption (CHO) improves performance in endurance exercises. However, depending on the type and quantity, CHO can cause gastrointestinal (GI) discomfort, which can worsen performance. Objective: to evaluate the effect of consuming different types of CHO on performance and GI discomfort in trained cyclists. Methods: On three occasions, with crossover, randomized, double-blind and placebocontrolled design, seven trained cyclists (age: 37.7 ± 3 years, relative peak power: 4.5 ± 0.4 W · kg-¹, VO2máx : 52.1 ± 5.5 ml · kg · min-¹) ingested Placebo (PLA), Maltodextrin (MAL) or Maltodextrin plus Fructose (MAL + FRU) and performed 45 min of exercise at 65% of peak power, immediately followed for 15 min of time trial cycling (TT). CHO solutions had a concentration of 8% and were offered in 1.5 g · min-¹, with MAL + FRU in the proportion of 2: 1 (maltodextrin: fructose). GI discomfort questionnaires were applied and blood was collected for plasma glucose analysis. Performance was assessed using the Smallest Important Difference (SWC) and the size of the Cohen D (ES) effect. Results: Complaints of GI discomfort were low and similar in the three groups (PLA 4.4 ± 3.2; MAL 5.5 ± 4.9; MAL + FRU 5.7 ± 5.8 p = 0.89). TT performance was better in the MAL + FRU situation when compared to PLA (distance covered: 8415.7 ± 772.6 m versus 7900.7 ± 345.5 m, respectively, 6.5%> SWC, ES = 0, 86) and it was no different between MAL versus PLA or MAL versus MAL + FRU. There was no difference in plasma glucose concentrations between groups. Conclusion: The consumption of MAL + FRU improved the performance of cyclists when compared to the consumption of placebo, but not in relation to the consumption of MAL in isolation. This improvement in performance does not seem to be related to GI symptoms, as there was no increase in GI discomfort in all groups evaluated.