International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance

Abstract

Based on a comprehensive review and critical analysis of the literature regarding the effects of sodium bicarbonate supplementation on exercise performance, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Supplementation with sodium bicarbonate (doses from 0.2 to 0.5 g/kg) improves performance in muscular endurance activities, various combat sports, including boxing, judo, karate, taekwondo, and wrestling, and in high-intensity cycling, running, swimming, and rowing. The ergogenic effects of sodium bicarbonate are mostly established for exercise tasks of high-intensity that last between 30 s and 12 min. 2. Sodium bicarbonate improves performance in single- and multiple-bout exercise. 3. Sodium bicarbonate improves exercise performance in both men and women. 4. For single-dose supplementation protocols, 0.2 g/kg of sodium bicarbonate seems to be the minimum dose required to experience improvements in exercise performance. The optimal dose of sodium bicarbonate dose for ergogenic effects seems to be 0.3 g/kg. Higher doses (e.g., 0.4 or 0.5 g/kg) may not be required in single-dose supplementation protocols, because they do not provide additional benefits (compared with 0.3 g/kg) and are associated with a higher incidence and severity of adverse side-effects. 5. For single-dose supplementation protocols, the recommended timing of sodium bicarbonate ingestion is between 60 and 180 min before exercise or competition. 6. Multiple-day protocols of sodium bicarbonate supplementation can be effective in improving exercise performance. The duration of these protocols is generally between 3 and 7 days before the exercise test, and a total sodium bicarbonate dose of 0.4 or 0.5 g/kg per day produces ergogenic effects. The total daily dose is commonly divided into smaller doses, ingested at multiple points throughout the day (e.g., 0.1 to 0.2 g/kg of sodium bicarbonate consumed at breakfast, lunch, and dinner). The benefit of multiple-day protocols is that they could help reduce the risk of sodium bicarbonate-induced side-effects on the day of competition. 7. Long-term use of sodium bicarbonate (e.g., before every exercise training session) may enhance training adaptations, such as increased time to fatigue and power output. 8. The most common side-effects of sodium bicarbonate supplementation are bloating, nausea, vomiting, and abdominal pain. The incidence and severity of side-effects vary between and within individuals, but it is generally low. Nonetheless, these side-effects following sodium bicarbonate supplementation may negatively impact exercise performance. Ingesting sodium bicarbonate (i) in smaller doses (e.g., 0.2 g/kg or 0.3 g/kg), (ii) around 180 min before exercise or adjusting the timing according to individual responses to side-effects, (iii) alongside a high-carbohydrate meal, and (iv) in enteric-coated capsules are possible strategies to minimize the likelihood and severity of these side-effects. 9. Combining sodium bicarbonate with creatine or beta-alanine may produce additive effects on exercise performance. It is unclear whether combining sodium bicarbonate with caffeine or nitrates produces additive benefits. 10. Sodium bicarbonate improves exercise performance primarily due to a range of its physiological effects. Still, a portion of the ergogenic effect of sodium bicarbonate seems to be placebo-driven.

Fig. 1

Schematic representation of the mechanism of HCO₃^- absorption in the stomach and the impact of sodium bicarbonate ingestion on muscle metabolism and selected blood parameters. Sodium bicarbonate ingestion increases the concentration of HCO₃^- in the stomach lumen, some of which neutralizes HCl to form CO₂ and increases luminal pH. The rise in pH stimulates the Cl^-/HCO₃^- antiporter in the parietal cells, which transports HCO₃^- into the extracellular fluid. This transport is coupled with the H-K-ATPase pump that secretes H⁺ into the stomach lumen to restore the pH. This results in increased pH and HCO₃^- concentration, which increases the activity of monocarboxylate transporters (MCT1 and MCT4, represented in light blue), thereby enhancing the transport of H⁺ out of muscle cells and improving intramuscular acid-base balance. Improved pH control in the muscle cells allows higher glycolytic rates, resulting in higher rates of ATP production and higher muscle and blood lactate concentrations. Solid lines indicate reactions. Dashed lines indicate transport across membranes or movement within the cell compartment. Created using BioRender.com

Fig. 2

Illustration of the contribution of different energy systems to the production of ATP to sustain maximal or near-maximal exercise over a given amount of time. The horizontal gradient-filled bars indicate exercise intensity/duration zones that are more (filled) or less (shaded) likely to result in acidosis and thus benefit from sodium bicarbonate supplementation