Sodium bicarbonate, a familiar old friend.
Sodium bicarbonate is back in the spotlight following its role in the 2026 London Marathon record and its growing presence within evidence-based sports supplementation.
When we face very high exercise intensities, the demand for ATP increases considerably. To sustain it, the flow through glycolysis increases.
This increase in glycolytic metabolism is associated with greater proton (H⁺) production. When the intensity is maintained over time, intracellular buffering systems begin to be insufficient, and a relative accumulation of H⁺ occurs, contributing to a decrease in intramuscular pH as part of the imbalance between energy production and utilization.
This more acidic environment can interfere with key processes involved in muscle contraction and promote the onset of fatigue along with a decline in performance, which is key for those looking for ways to improve sports performance with sodium bicarbonate:
- Decreased efficiency of contractile proteins
• Disruption of calcium homeostasis
• Reduced ability to generate force and power
This is where sodium bicarbonate comes into play.
It acts primarily as an extracellular buffer. By increasing the concentration of bicarbonate in the blood, the ability to buffer H⁺ increases, maintaining the gradient between the muscle and the blood. This gradient facilitates the removal of H⁺ from the muscle fiber through specific transporters, helping to delay muscle fatigue and the decline in intramuscular pH.
The result is a greater capacity to sustain high-intensity efforts in which glycolysis is a determining factor.
That is why its effect is observed mainly during efforts lasting approximately 1 to 10 minutes: 800 m, 1500 m, rowing, track cycling, CrossFit, or HYROX, among others.
In marathon running, its impact is smaller, although it may be useful at certain moments, such as pace changes, inclines, sprints, etc…
The dose most commonly used in the scientific literature is 0.2–0.3 g/kg of body weight, administered between 60 and 180 minutes before exercise, although the optimal timing depends on individual tolerance.
Its main limitation remains gastrointestinal tolerance, with possible effects such as nausea, diarrhea, abdominal distension, or general discomfort.
For this reason, more advanced strategies have emerged, such as encapsulated formulations or formulations combined with hydrogels, designed to improve tolerance without compromising the ergogenic effect.
In addition, sports performance does not depend solely on supplementation. Maintaining consistent training, rest, hydration, and nutrition habits remains essential for optimizing performance and delaying muscle fatigue in the long term.
If you are getting back into training or want to improve your adherence to sport, you may also be interested in our article on how to effectively restore your habits and get back into your sports routine.
Author: Marcos Rueda Córdoba
Grgic, J., Grgic, I., Del Coso, J., Schoenfeld, B. J., & Pedisic, Z. (2021). Effects of sodium bicarbonate supplementation on exercise performance: an umbrella review.Journal of the international society of sports nutrition,18(1), 71.
Gurton, W. H., King, D. G., Ranchordas, M. K., Siegler, J. C., & Gough, L. A. (2024). Enhancing exercise performance and recovery through sodium bicarbonate supplementation: introducing the ingestion recovery framework.European journal of applied physiology,124(11), 3175-3190.
Keverkamp, L., & Scanlon, K. (2025). Physiological effects of sodium bicarbonate ingestion via Maurten Bicarb on endurance running performance.Journal of the International Society of Sports Nutrition,22(sup2), 2550173.