Purpose Citrulline (CIT) and beetroot extract (BR) supplements positively impacts exercise performance in elite rowers. However, its influence on metabolic outcomes such as whole-body volumes of oxygen consumption (VO2) and carbon dioxide production (VCO2), substrate oxidation, energy expenditure (EE), and gross efficiency remains unknown. We studied the effects of 1 week of daily co-supplementation of 3.5 g BR (500 mg NO3-) plus 6 g CIT on VO2 and VCO2 kinetics, substrate utilization, EE, and gross efficiency in elite male rowers compared to a placebo and to a BR supplementation. Methods Twenty elite rowers participated in this randomized, double-blind, placebo-controlled crossover trial completing 1 week of supplementation in each group of study: Placebo (PLAG); BRG; and BR-CITG. Efficiency (70% VO2max) and performance (incremental maximal) tests were performed, and gas-exchange data were collected via indirect calorimetry. Results Analysis of covariance (ANCOVA) showed no mean between-condition differences on respiratory exchange ratio (RER), EE, and gross efficiency in the efficiency test (all P > 0.06), and in the performance test (all P > 0.28). Moreover, in both tests no interaction Time × Supplement effects were observed for VO2, VCO2, RER, EE, substrate oxidation, and, gross efficiency (all P > 0.12). Conclusion After 1 week, no effects on energy metabolism and substrate utilization were observed after the daily co-ingestion of BR extract plus CIT supplement, therefore longer (> 7 days) and higher doses of supplementation might be needed to influence metabolism.
© Copyright 2024 European Journal of Applied Physiology. Springer. Alle Rechte vorbehalten.