How Does Sodium Bicarbonate Work? Bicarb Benefits as a Lactate Buffer.

Bicarb benefits have been widely reported in sports-science and physiology literature and sodium bicarbonate has become more and more popular as a lactate buffer and an ergogenic aid to boost performance in running and other sports.

Does Bicarb really work?

In short, yes bicarbonate can improve sports performance, particularly in high-intensity efforts lasting 1 – 10 minutes. The benefits can vary between individuals and the exact sporting challenge and its demands, but multiple research studies demonstrate a benefit (Grgic et al, 2020).

Bicarbonate works as a buffer, helping to neutralise the acid (hydrogen ions) that can accumulate in the muscles and blood during hard exercise. This can delay fatigue and allow athletes to sustain higher intensities for longer—especially in events like middle-distance running or short cycling time trials. However, the effect is not universal; some athletes see clear gains, while others experience little benefit or gains are limited by side effects like gastrointestinal discomfort.

The evidence base is fairly strong for short-duration, high-intensity endurance efforts. A 2023 meta-analysis of randomized controlled trials found that sodium bicarbonate supplementation significantly improved cycling time-trial performance and mean power output compared to placebo, indicating a small but meaningful ergogenic effect (Lopes-Silva and Correia-Oliveira, 2023). These improvements are typically in the range of ~1–3%, which can be decisive in competitive settings but less noticeable for recreational athletes.

Individual studies support these findings. For example, a double-blind crossover trial showed that bicarbonate ingestion improved mean power output by about 3% during a final sprint after a prolonged cycling race. Similarly, research on trained cyclists demonstrated improved 4 km time-trial performance when bicarbonate timing was individualised to peak blood buffering levels.

Running studies also suggest benefits in time-to-exhaustion and high-intensity efforts, though results are more variable depending on protocol and athlete level. Overall, bicarb does work, but it’s best suited to trained athletes performing intense efforts—and its practical use is often limited by dosing challenges and side effects.

How does Sodium Bicarb work?

Sodium bicarb acts as a buffering agent against acid build up in the muscles. During high-intensity exercise, especially activities like sprinting or repeated intervals, the body relies more on anaerobic metabolism, which leads to the production of hydrogen ions and a drop in muscle pH (a process thought to be linked to fatigue). This condition, often associated with lactic acid build up, can impair muscle contraction and energy production. When sodium bicarbonate is ingested before exercise, it increases the concentration of bicarbonate in the blood, helping to neutralize excess acidity and maintain a more stable pH level.

By reducing the rate at which muscles become acidic, sodium bicarbonate allows athletes to sustain high-intensity efforts for longer periods and delay fatigue. This is particularly beneficial in sports that involve repeated bursts of effort, such as middle-distance running, rowing, or team sports. The enhanced buffering capacity also improves the gradient for hydrogen ions to move out of muscle cells into the bloodstream, further protecting muscle function. As a result, athletes may experience improved power output, endurance during intense efforts, and overall performance in events where acid accumulation would normally limit output.

How does Bicarb benefit performance?

In short, bicarb delays muscle acidosis allowing athletes to maintain high intensity output for longer, before fatigue forces a reduction in intensity. Increase time to exhaustion has been shown in various different high intensity exercise trials (Lino et al, 2021)

During high intensity exercise the body meets rising energy demand by increasing anaerobic metabolism, resulting in lactic acid production. Bicarbonate of sodium has been shown to counteract the build up of H+ ions, associated with increasing acidity, during high intensity exercise. This has been shown to be particularly effective in 2km rowing trials, repeated sprint running workouts, high rep count resistance training, and cycling performance (Siegler et al, 2016).

Is bicarb an ergogenic aid?

Sodium bicarbonate is widely considered an ergogenic aid in sport, and has strong support within peer-reviewed literature. As a performance booster bicarb is not banned by WADA or any anti-doping authority.

In sports science, an ergogenic aid is anything that enhances physical performance. Sodium bicarbonate fits this definition because it improves the body’s ability to buffer acid during high-intensity exercise, delaying fatigue and allowing athletes to sustain effort longer. Because of this, it’s commonly used in events like cycling, sprinting, rowing, and middle-distance running, where acid accumulation can limit performance.

Can bicarb improve running performance?

Bicarb has been a popular supplement to fight lactic acid amongst middle distance athletes and even long distance (marathon) runners. There is strong evidence that bicarb improves muscular endurance, without having any significant improvement on muscular strength, showing bicarb is a helpful aid for running performance.

Notably Lassen et al (2021) assessed the blood chemistry whilst administering personalised timing of bicarb supplementation for elite runners. Bicarb intake resulted in reduced muscle acidosis, delayed fatigue, and significant improvement in 800m and 1500m performance. 

Moreover the effect was improved when individuals timed their dosage in relation to the trial, after determining each athlete’s time to peak blood bicarbonate concentration after consumption. This obviously required 2 laboratory visits, but highlights that personalisation of the timing of dose allows the biggest gains without necessarily increasing the dose.

When should I use Bicarb?

The timing of bicarb ingestion before sporting performance is important in maximising the potential ergogenic effect. Most research and bicarb products suggest consuming 2 to 3 hours before competition, with the aim of maximising bicarbonate levels in the blood at the time of the high intensity exercise (competition or race)

In a recent running-based trial, bicarbonate levels in the blood peaked between 60 – 180 minutes post consumption (Lassen et al, 2021) showing a range between individuals. The method of consumption can also play a role; for example VOOM Bicarb Charger delivers the sodium bicarb in an enteric coated capsule to reduce risk of GI upset, but this means the capsules should be taken 2 to 4 hours before competition.

Will bicarb upset my stomach for running?

Whilst strong research supports the benefit of bicarb, there is also regular reference to the risk of gastrointestinal distress, so testing before a race or competition can help ease concerns. GI distress is highly individual –  some athletes tolerate sodium bicarb well, while others experience significant side effects that can outweigh any performance benefit.

Scientifically speaking, once in the stomach bicarb reacts with stomach acid (hydrochloric acid) and produces carbon dioxide gas. This chemical reaction can lead to symptoms like bloating, nausea, stomach cramps, and diarrhoea. The rapid production of gas increases pressure in the stomach, which is why athletes often report discomfort or an urgent need to use the bathroom before or during exercise. In higher doses (typically 0.3g + per kg of body mass, which is standard for performance benefits), these side effects become more likely.

That being said, the enteric coating of the VOOM Bicarb capsules allows the capsules and bicarb to move further down the system towards the small intestine before releasing the bicarb to be absorbed into the body, which reduces the risk of GI discomfort.

If you think a sodium bicarb supplement could be a performance booster for you, why not check out the VOOM bicarb calculator which gives you a personalised dose and timing recommendation for this highly effective lactate buffer.