1. Introduction
SECONDARY
Nitrates are an effective ergogenic supplement; however, the effects of nitrate supplements based on habitual dietary nitrate intake through diet alone are not well understood. We aimed to assess this in a group of 15 highly trained football players from Slovenian football’s First Division. Participants underwent two separate Cooper performance tests either with nitrate supplementation (400 mg nitrates) or placebo while having their nutrition assessed for nitrate intake, as well as energy and macronutrient intake. Nitrate supplementation had a statistically significant positive effect on performance if baseline dietary nitrate intake was below 300 mg (Nitrates, found predominantly in green leafy and root vegetables, have been studied extensively for their possible ergogenic benefits through a wide variety of sports modalities and exercise lengths [The formation of nitric oxide is stimulated either through the ingestion of nitrate-rich foods, and to a certain degree through endogenous synthesis through the oxygenation of the amino acid L-arginine to citrulline, followed by the oxygenation of citrulline to nitric oxide [While many studies have examined the effectiveness of nitrates on different aspects of physical performance [Previous research indicates that nitrate supplementation is less effective in well-trained individuals, defined in this case as athletes having a maximal oxygen uptake (VO2max) below 65 mL/kg/min [Thus, the purpose of this article was to find out the effects of nitrate supplementation on performance depending on different baseline levels of athletes’ habitual dietary nitrate intake on a sample of elite football players from the First Division of Slovenian football. Based on this, the following hypotheses were determined:


An amount of 300 mg of baseline dietary nitrate intake was chosen as a reference value for performance comparison, as previous research has reported that at least 300 mg of nitrates is needed to improve exercise performance [The main objective of this study was to examine the effects of nitrate supplementation on performance as a function of the habitual dietary intake of nitrates on a sample of elite Slovenian football players, with perceived exertion being the secondary response variable. The main conclusions of this study are that nitrate supplementation augments performance when dietary nitrate intake is below 300 mg, with nitrates having no significant effect on perceived exertion during exercise. The average nitrate intake of Slovenian First Division football players was 165 mg, with nitrates being consumed mostly from leafy vegetables.