Dietary nitrate supplementation reduces performance decline during repeated sprint exercise independent of sex

Dietary nitrate supplementation has been shown to improve endurance exercise performance, but its effects on repeated anaerobic sprints and potential sex-based differences remain underexplored. This study examined whether acute dietary nitrate supplementation reduces performance decline during repeated Wingate sprints and whether responses differ between sexes. The secondary aim was to investigate the potential central and peripheral mechanisms. Using a randomized crossover design, 19 males and 17 females (all recreational athletes) consumed dietary nitrate supplementation in the form of nitrate-rich beetroot juice (~13 mmol NO₃ ^-) or placebo 2.5 hours prior to completing four 30-second maximal cycling sprints. The primary outcomes included power output and total work changes from the first to the last sprint. To investigate the potential mechanisms, corticospinal excitability and muscle microvascular function were also measured prior to sprints. No sex by supplement interactions were observed (all p > 0.05) for any of the measured parameters. Dietary nitrate supplementation significantly attenuated the decline in performance across repeated sprints, with large main effects on peak power, mean power, power decline, and total work (all p < 0.05). However, dietary nitrate supplementation did not affect corticospinal excitability or muscle microvascular reactivity (all p > 0.05). Acute dietary nitrate ingestion effectively mitigates fatigue development during repeated anaerobic efforts; however, no sex differences were detected. The observed performance benefits occurred without detectable changes in resting measures of corticospinal excitability or microvascular reactivity.