Acute Effects of Nitrate-Rich Beetroot Juice on Cardiovascular and Hemodynamic Responses to Flywheel Resistance Exercise: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial

Background/Objectives: Beetroot juice is a popular nutritional resource in sports due to its ergogenic effects, promoting vasodilation, hypotension, improved energy efficiency, and reduced oxygen cost. However, its role in modulating the autonomic nervous system during strength training remains understudied. This study assessed the effects of acute nitrate-rich beetroot juice supplementation on cardiovascular and hemodynamic responses to flywheel resistance exercise. Methods: Fifteen male participants (age 22 ± 3.64 years) from the Federal University of Viçosa completed a crossover, double-blind, placebo-controlled trial. Each participant consumed either 400 mg of standardized nitrate or a placebo before performing 4 sets of 8–12 repetitions at 100% of their maximum concentric strength using a leg extension exercise, with 90 s recovery intervals. Heart rate, blood pressure, oxygen saturation, and subjective perception of effort were measured after each set. Data were analyzed using SPSS 23, employing the Shapiro–Wilk normality test, t-test for related samples, and MANOVA with time and supplement factors. Results: NO3− supplementation led to a smaller increase in systolic blood pressure (SBP) during exercise compared to the placebo and reduced diastolic blood pressure (DBP) in the last set, reflecting decreased peripheral vascular resistance. However, no significant effects were observed for heart rate, rate–pressure product, oxygen saturation, time under tension, or subjective perception of effort. Conclusions: These findings suggest that NO3− supplementation can offer cardiovascular benefits by attenuating blood pressure increases during strength training, highlighting its potential as a low-risk ergogenic aid for healthy young men.