Abstract Background: The beneficial effects of pyruvate on lactic acidosis and energy metabolism have been studied. The ability to attenuate acidosis and improve aerobic system contribution are essential for team sports athletes to perform multiple sprints in a limited time. This study aimed to investigate the impact of pyruvate supplementation on energy metabolism and lactic acidosis during high-intensity interval exercise (HIIE) and to evaluate its role in repeated sprint exercise (RSE) performance.Methods: Fourteen national-level male soccer athletes from China Football College (age: 20 ± 2 years, body fat: 13.11 ± 3.50%) participated in a randomized, double-blind, crossover study. Each subject underwent two HIIE and RSE tests after one week of supplementation with 0.1g/kg/d of pyruvate or placebo. Venous blood gas (pH, bicarbonate (HCO3-), base excess (BE) and oxygen partial pressure (pO2)) were measured at baseline, pre-HIIE, post-HIIE, pre-RSE and post-RSE. Finger-stick capillary lactate were collected at baseline, immediately after each bout of HIIE, and 3, 5, 7 and 10 min post HIIE. The energy system contributions during HIIE and exercise performance of RSE were analyzed. Results: Blood pH (p < 0.01), HCO3- (p < 0.01) and BE (p < 0.01) were significantly lower than their baseline levels at post-HIIE, pre-RSE and post-RSE in both Group pyruvate (PYR) and Group placebo (PLA), respectively. Blood pH, HCO3- and BE were significantly improved in PYR at pre-HIIE (p < 0.01), post-HIIE (p < 0.01) and pre-RSE (p < 0.01) than in PLA. Furthermore, blood BE remained higher in PYR than in PLA until the end of RSE (p < 0.05). Blood pO2 was higher at post-HIIE (p < 0.05), pre-RSE (p < 0.01) and post-RSE (p < 0.01), compared to baseline, in two groups and further higher in PYR than in PLA at post-HIIE (p < 0.05) and post-RSE (p < 0.05). During HIIE, the contribution of the aerobic system in the fourth bout of HIIE was higher in PYR than in PLA (p < 0.05). The contribution of the anaerobic energy was higher than that of the aerobic energy in PLA (p < 0.01), but without difference in PYR (p > 0.05). In addition, compared with PLA, the relative peak power (RPP) of the first and fifth sprints, the relative average power (RAP) of the fifth sprint and the average of RPP and RAP during RSE were significantly improved in PYR (p < 0.05). However, the blood lactate (p > 0.05), PD% of each bout (p > 0.05) or average PD% of RSE (p > 0.05) showed no significant difference between the two groups. Conclusion: Pyruvate supplementation with 0.1g/kg/d for a 1-week enhances aerobic metabolism and buffers exercise-induced metabolic acidosis but not lactic acidosis during HIIE, improving RSE performance in moderate acidosis. Thus, after 1 week pyruvate supplementation, athletes are expected to balance aerobic and anaerobic energy contributions and attenuate metabolic acidosis during team sports, improving exercise performance.

Effects of Sodium Pyruvate on Exercise-Induced Lactic Acidosis and Exercise Performance