The effect of pre‐exercise hyperventilation on repeated high‐intensity inclined sprint performance

High‐intensity exercise induces systemic acidosis, which contributes to muscular performance decline. Controlled pre‐exercise hyperventilation has been proposed as a non‐invasive intervention to induce respiratory alkalosis and counteract acidosis‐related acute fatigue. In this study, we hypothesized that a real‐world‐applicable pre‐exercise hyperventilation protocol can improve incline sprint performance. This randomized, single‐centre, controlled crossover study included 36 recreational athletes aged 18–40 years. Each participant completed a series of three inclined treadmill interval sprints on two separate days: one with pre‐exercise hyperventilation and one without. Respiratory parameters were measured via spirometry, and post‐sprint capillary blood gas analysis was performed. Pre‐exercise hyperventilation resulted in higher mean CO 2 elimination during hyperventilation (32.8 ± 5.1 vs. 21.5 ± 2.5 mL/kg, P < 0.0001) and lower mean end‐tidal CO 2 partial pressure (17 ± 2.5 mmHg vs. 30 ± 2.7 mmHg, P < 0.0001) compared to control condition. Mean cumulative elevation gain did not differ between pre‐exercise hyperventilation (83.2 ± 27.6 m) and control condition (84.3 ± 26.0 m, P = 0.6461). Differences in CO 2 elimination did not correlate with differences in performance ( P = 0.5905). We found no alterations in post‐sprint capillary blood lactate and pH between the two conditions ( P > 0.05 for all sprints cumulatively and separately). Participants subjectively assessed the breathing protocol as unpleasant, and felt it negatively influenced their performance. The easily translatable pre‐exercise hyperventilation protocol investigated in this study did not improve performance in repeated high‐intensity incline sprint intervals. Therefore, we discourage its application in real‐world applications.