Suplementação de nitrato em ciclistas de curta e longa distâncias : uma revisão sistemática de ensaios clínicos randomizados

Abstract

Dietary nitrate, from sources such as beetroot juice, has shown potential as an ergogenic aid in exercise performance. Studies have shown a possible significant reduction in oxygen cost during activities such as cycling after nitrate supplementation. This improvement in exercise efficiency, however, may not directly translate into a performance gain for athletes. Objective: To evaluate the possible effects of isolated nitrate supplementation on the performance of short- and long-distance cyclists. Methodology: This study is a systematic review of the literature conducted in the EMBASE, PubMed and Web of Science databases with the following descriptors: “Nitrates”, “Nitrate”, “Exercise”, “Physical Activity”, “Physical Exercise”, “Aerobic Exercise”, “Training, Exercise”, “Athletic Performance” and “Bicycling”. Randomized clinical trials, with no restrictions on year and language, conducted with healthy adults who regularly performed short- and/or long-distance cycling were selected. The outcomes of interest are performance, power, lactate concentration, blood pressure and heart rate, oxygen consumption and perceived exertion. The systematic review protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO identifier number CRD42024497141). Results: Sixteen studies, published between 2011 and 2019 and all in English, were selected. The follow-up time of the studies ranged from 01 to 08 days, with most samples with male individuals and only one study with a female sample. Nitrate supplementation ranged from 4.1 mmol/L to 12.9 mmol/L per day and sodium nitrate from 0.0555 mmol/L to 12.8 mmol/L per day. Performance was assessed in all studies and only four showed a statistically significant improvement in this outcome. Power was assessed in 11 studies and only four showed an improvement. Lactate concentration was analyzed in six studies and two showed an improvement in this parameter. Regarding cardiorespiratory parameters and perceived exertion, there were again no significant effects of isolated nitrate supplementation. Conclusion: Nitrate supplementation did not show consistent effects in improving cyclists' performance.