Effect of sodium bicarbonate contribution on energy metabolism during exercise: a systematic review and meta-analysis

Background The effects of sodium bicarbonate (NaHCO3) on anaerobic and aerobic capacity are commonly acknowledged as unclear due to the contrasting evidence thus, the present study analyzes the contribution of NaHCO3 to energy metabolism during exercise. Methods Following a search through five databases, 17 studies were found to meet the inclusion criteria. Meta-analyses of standardized mean differences (SMDs) were performed using a random-effects model to determine the effects of NaHCO3 supplementation on energy metabolism. Subgroup meta-analyses were conducted for the anaerobic-based exercise (assessed by changes in pH, bicarbonate ion [HCO3-], base excess [BE] and blood lactate [BLa]) vs. aerobic-based exercise (assessed by changes in oxygen uptake [VO2], carbon dioxide production [VCO2], partial pressure of oxygen [PO2] and partial pressure of carbon dioxide [PCO2]). Results The meta-analysis indicated that NaHCO3 ingestion improves pH (SMD = 1.38, 95% CI: 0.97 to 1.79, P < 0.001; I-2 = 69%), HCO3- (SMD = 1.63, 95% CI: 1.10 to 2.17, P < 0.001; I-2 = 80%), BE (SMD = 1.67, 95% CI: 1.16 to 2.19, P < 0.001, I-2 = 77%), BLa (SMD = 0.72, 95% CI: 0.34 to 1.11, P < 0.001, I-2 = 68%) and PCO2 (SMD = 0.51, 95% CI: 0.13 to 0.90, P = 0.009, I-2 = 0%) but there were no differences between VO2, VCO2 and PO2 compared with the placebo condition. Conclusions This meta-analysis has found that the anaerobic metabolism system (AnMS), especially the glycolytic but not the oxidative system during exercise is affected by ingestion of NaHCO3. The ideal way is to ingest it is in a gelatin capsule in the acute mode and to use a dose of 0.3 g center dot kg(- 1) body mass of NaHCO3 90 min before the exercise in which energy is supplied by the glycolytic system.