Effects of Pyruvate Supplementation on High-intensity Interval Exercise Induced Metabolic Acidosis and Repeated Sprint Exercise Performance of College Soccer Athletes

Abstract Background: The effects of pyruvate on metabolic acidosis and oxidative metabolism had been studied. The ability to attenuate acidosis and improve oxidative system contribution are critical to the performance of team sport athletes during perform multiple high-intensity exercise over a limited period of time. This study aimed to investigate the impact of pyruvate supplementation on energy metabolism and metabolic acidosis during high-intensity interval exercise (HIIE), as well as to evaluate its role on repeated sprint exercise (RSE) performance.Methods: 14 well-trained male college soccer athletes (age: 20 ± 2 years, body fat: 13.11 ± 3.50 %) were studied in a randomized, double-blind, cross-over study. The participants ingested either 0.1g/kg/d of pyruvate or a placebo for 1-week. Metabolic acidosis was induced by HIIE after the supplement period, and RSE ability in the acidosis state was assessed. Venous blood pH, bicarbonate (HCO3-) and base excess (BE) were measured at baseline, pre-HIIE, post-HIIE, pre-RSE and post-RSE. Finger-stick blood lactate were collected at baseline, immediately after each bout of HIIE and 3, 5, 7, 10 min after HIIE. The energy systems contribution during HIIE were estimated. Results: Blood pH, HCO3- and BE were significantly lower than baseline after HIIE (p < 0.01) in both pyruvate group (PYR) and placebo group (PLA). Compared to PLA, the 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). Furthermore, blood BE remained higher in PYR than PLA till end of RSE (p < 0.05). The contribution of oxidative system in the fourth bout of HIIE was higher in PYR than PLA (p < 0.05). In PLA, the ratio of total anaerobic energy contribution during HIIE was higher than that of aerobic (oxidative) (p < 0.01), but not in PYR (p > 0.05). Relative peak power (RPP) of first, fifth sprint, relative average power (RAP) of fifth sprint, the average of RPP and RAP during RSE were significantly improved in PYR compared with PLA (p < 0.05). While no significant changes in the PD% of each bout (p > 0.05) or average PD% (p > 0.05) were observed between the two groups. Conclusion: Pyruvate supplementation for 1-week enhances oxidative system energy contribution and buffers metabolic acidosis during HIIE, and improves RSE performance in acidosis.