Efeitos da suplementação aguda e crônica de nitrato no desempenho de membros superiores em mulheres praticantes de exercício resistido

Abstract

Introduction: Nitrate (NO3-) has been investigated as a potential ergogenic aid due to its conversion into nitric oxide (NO), a molecule associated with blood flow regulation, tissue oxygenation, and muscular contractile efficiency. In parallel, the growing interest in improving performance during resistance exercise has increased the search for strategies capable of optimizing physical performance. Rationale: However, the effects of nitrate supplementation on resistance training remain inconclusive, especially in women, a population that has been understudied and may present physiological responses different from those observed in men. Objective: To evaluate the effects of acute and chronic nitrate supplementation on upper-limb physical performance in women engaged in resistance training. Methodology: This was an experimental, randomized, double-blind, placebo-controlled study approved by the Research Ethics Committee. Twenty-six trained women participated (Nitrate: n=13; 21.2 ± 2.12 years; Placebo: n=13; 22.8 ± 2.97 years), all with at least 5 months of resistance training experience. Four visits were conducted: one familiarization session, including physical and nutritional assessments, load determination, and signing of the informed consent form; and three experimental sessions: control (without supplementation), acute (single dose), and chronic (daily dose for 5 consecutive days). In each session, participants performed supinated lat pulldown and bent-over row exercises (4 sets of 12 repetitions at 60% of 1RM), followed by 4 sets to failure in the pronated lat pulldown exercise at 75% of 1RM. The total number of repetitions, maximal voluntary isometric contraction (MVIC), heart rate (HR), blood pressure (BP), blood lactate, time under tension (TUT), and rating of perceived exertion (RPE) were evaluated. Data were analyzed using IBM SPSS Statistics through Generalized Linear Mixed Models (GLMMs). Results: There was a significant increase in the total number of repetitions performed to failure in both groups. However, the Nitrate group showed greater effect sizes (acute: d=1.31; chronic: d=1.63) compared with the Placebo group (d=0.59 and d=1.15, respectively). This greater performance occurred without corresponding increases in RPE, HR, BP, or blood lactate concentrations. For MVIC, the group × condition interaction showed a near-significant trend (p=0.051) toward attenuation of strength loss in the nitrate group, 3 minutes after the end of the session. For TUT, significant differences were observed only between conditions, with a progressive increase in both groups. Conclusion: Nitrate supplementation demonstrated ergogenic potential in women engaged in resistance training, increasing total training volume without elevating metabolic cost or perceived exertion.