What is one of the most-researched sports supplements with proven benefits? The answer may surprise you because it’s probably sitting in your kitchen cabinets now: sodium bicarbonate.
Commonly known as baking soda, this everyday item is recognized by the International Olympic Committee as one of the top five supplements for enhancing performance in specific sports scenarios. In fact, according to one leading coach, 80% of endurance athletes at the 2024 Paris Olympics used sodium bicarbonate to boost their performance.
But how exactly does sodium bicarbonate improve performance? Which athletic scenarios does it benefit most? And are there any potential drawbacks should athletes know about? In this article, we’ll answer these important questions.
Quick Recap: Sodium bicarbonate increases time until fatigue, allowing athletes to push harder during short periods of high-intensity. It likely works by reducing acidity and/or phosphate buildup in muscles. Because sodium bicarbonate can cause digestive issues, it’s important to take it in a gastro-resistant form and get the timing and dosage right.
How Does Sodium Bicarbonate Help Athletic Performance?
The most common reason cited for sodium bicarbonate’s benefits is that it buffers the blood, i.e. making it less acidic, which facilitates the removal of hydrogen ions from the muscles, allowing them to return to a less-acidic state.
Let’s break this down in more detail.
ATP Breakdown and Acidosis
Adenosine triphosphate (ATP) is the primary energy currency of cells, powering nearly all bodily functions, including muscle contractions. The body breaks down glucose, glycogen (the stored form of glucose), creatine phosphate, proteins, and/or fats to form ATP molecules.
As the body breaks down ATP for energy, it produces various byproducts, including hydrogen ions (H+). The excess hydrogen causes muscle cells to become more acidic. This is known as acidosis.
Pro Fact: Lactate Is Not to Blame.During anaerobic exercise, the body produces lactate (often incorrectly called lactic acid). Hydrogen ions are transported with lactate. So, for many years, lactate was blamed for the buildup of hydrogen.
However, research now shows that ATP breakdown is the primary source of hydrogen ions. Further, lactate is actually helpful because it buffers these hydrogen ions, delaying acidosis and allowing continued energy production.
Muscle Acidity and Its Impact on Performance
The body tightly regulates pH levels to optimize cellular function. Resting muscle cells have a pH of around 7.0, but during intense activity, muscle pH can drop significantly. Research theorizes that this shift in acidity can impair:
- Enzyme activity involved in energy production.
- Calcium handling, which is essential for muscle contraction.
- ATP hydrolysis, reducing available energy.
- Muscle fiber recruitment, leading to diminished strength and endurance.
The increased acidity may also be responsible for the “burning” sensation during intense exercise, though its role in muscle fatigue is still debated.
How Much Impact Does It Have?
It’s important to remember pH is measured on a logarithmic scale, meaning a 1-unit change in pH equals a tenfold change in hydrogen ion concentration. Therefore, even a small change in pH represents a significant biological change.
For example, in one study, researchers found that high-frequency muscle contractions caused the pH of muscle cells in the soleus (a lower leg muscle) to drop from 7 to as low as 6.2.
At 15°C, this drop in pH caused:
- 32% reduction in muscle force
- 19% reduction in speed of contraction
- 23% reduction in peak power
At 30°C, muscle force was only reduced by 6%. However, contraction speed and peak power saw much greater declines: 24% and 30%, respectively. This suggests that while muscles maintain greater strength at higher temperatures, they become slower and less powerful.
The Role of Bicarbonate
The kidneys naturally produce bicarbonate (HCO₃⁻). Its primary job is to bind to excess hydrogen ions to maintain proper pH levels.
During low-intensity exercise, the body can generally produce enough bicarbonate on its own. However, during high-intensity exercise, the body can produce so many hydrogen ions that the body can’t clear them away fast enough—leading to an accumulation of hydrogen and acidity.
To counteract this, athletes can supplement with bicarbonate. It increases the buffering capacity of the blood, and thus increases the transport of hydrogen ions out of the muscles so they return to a less acidic state.
Pro Fact: Lactate is transported along with hydrogen atoms, so lactate transport from cells also increases. That is why lactate concentrations are usually higher when athletes are using sodium bicarbonate.
Is Muscle Fatigue Really Caused by Acidity?
Despite decades of research, the precise cause of muscle fatigue remains unclear. While increased acidity from hydrogen ions is widely cited to be the cause, research shows that phosphate accumulation may actually be the culprit.
Phosphate, a byproduct of phosphocreatine breakdown, interferes with calcium release and uptake in muscle cells, impairing contraction.
While bicarbonate doesn’t directly remove phosphate, its buffering action on hydrogen ions indirectly supports phosphate clearance by maintaining cellular homeostasis.
Thus, this may be the real reason behind sodium bicarbonate’s benefits— though it's possible that a combination of factors, including buffering effects on both hydrogen ions and phosphate, are really behind sodium bicarbonate’s performance-enhancing benefits.
When to Use Sodium Bicarbonate
While we don't know exactly why sodium bicarbonate works, we know it does work—but only for certain specific scenarios:
1. Very intense workouts above FTP or Critical Power.
This usually means short (2-15 minutes) high-intensity efforts, such as sprints and middle-distance events. For example, Keely Hodkinson, the 2024 Olympic Gold Champion, famously uses sodium bicarbonate.
2. Endurance events were power output varies.
Even though it is best associated with shorter events, sodium bicarbonate benefits endurance athletes whose power output varies during the event.
In other words, if you are doing a long race where you will have periods of higher intensity—such as steep climbs or want to have an all-out finish—then sodium bicarbonate can help.
Can Sodium Bicarbonate Help Adaptations?
Sodium bicarbonate is mostly commonly used to aid performance. However, sodium bicarbonate may also support adaptations—so it shouldn’t be reserved solely for competitions.
As Dr. Tim Podlogar points out, sodium bicarbonate allows you to push harder, and this increase in intensity in itself will support adaptations. Further, Podlogar says that sodium bicarbonate could provide a better environment for mitochondrial function, as mitochondria thrive in less acidic conditions.
However, the evidence on this is not as strong as the performance benefits of sodium bicarbonate.
Side Effects of Sodium Bicarbonate
While the bicarbonate part of sodium bicarbonate will not cause any negative consequences, the sodium part of the molecule can cause some problems.
Diarrhea
Consuming too much sodium in a single dose can draw water from the bloodstream into the intestines. This disrupts normal fluid balance and can lead to digestive issues, such as diarrhea, which no one wants during a race. This is why it is important to divide up sodium bicarbonate into several smaller doses.
Water Retention
Sodium attracts water into tissues, leading to water retention. This is why you may notice a higher body mass when weighing yourself after taking sodium bicarbonate. The water retention can cause bloating and an uncomfortable feeling of heaviness.
Belching
When you consume sodium bicarbonate, part of the bicarbonate reacts with your stomach acid to produce carbon dioxide (CO₂). Because CO₂ is a gas, the body needs to release the gas, which can result in belching as well as bloating.
How to Use Sodium Bicarbonate
To get the benefits of sodium bicarbonate for performance while avoiding potential side effects, it is important that you take it properly.
Here are the key guidelines.
- Dosage: Consume 2 and 0.3 g of sodium bicarbonate per kilogram of body mass before exercise.
- Timing: Take the first half of the dosage 120 before exercise begins and the second half of the dosage 60 minutes before the exercise begins.
- Splitting Dosage: Break the dosage into two smaller dosages.
- Topping Up: During exercise that lasts longer than 3 hours, consume 5 g of sodium bicarbonate per hour.
- Form: Take in a gastro-resistant form, such as tablets or coated capsules.
- Combining with Other Supplements: Using sodium bicarbonate with beta alanine may increase benefits. It is unclear whether there are added benefits of combining it with caffeine.
For more detailed info, read our sodium bicarbonate ingestion protocol.
