Sodium Bicarbonate for Sport: Does Baking Soda Work?

Sodium bicarbonate — known at home as baking soda, in sport usually as bicarbonate — is one of the few supplements with genuine performance data behind it. Unlike most shelf miracles, it is not marketing but a measurable physiological mechanism: bicarbonate buffers the acid that builds up in the muscle during intense effort. The catch: the effect applies almost only to short, hard efforts — and it comes with exactly the stomach trouble no athlete wants. Here is what bicarbonate really does, which disciplines benefit and how to use it tolerably.

What bicarbonate actually does in the body

During intense effort the body increasingly draws its energy from glycolysis — the rapid breakdown of sugar without oxygen. This produces hydrogen ions that lower the pH in the muscle, making it acidic. That acidosis slows muscle contraction and is one reason a sprint pace can only be held for a few minutes. The body counters with its own buffer system: bicarbonate in the blood neutralises the acid leaving the muscle and keeps pH stable for longer.

The idea behind the supplement is simple: giving the body extra bicarbonate expands its buffering capacity — and with it the time window during which it can sustain high intensity. This is a clean, repeatedly reproduced mechanism, not a placebo. The catch lies in the time frame: the buffer only acts where acid load is genuinely high — during the anaerobic, high-intensity phase.

What the research shows

Meta-analyses of bicarbonate supplementation give a consistent picture: for efforts lasting roughly one to ten minutes, the performance gain is in the range of one to three percent. This covers distances such as 800, 1,500 and 5,000 metres, track cycling events, 200-metre swimming, 2,000-metre rowing and sports with many short, hard surges.

Three percent decides races in these disciplines — over a 1,500-metre race that is more than two seconds. For longer efforts the effect almost disappears: for the marathon, half marathon, long-distance triathlon or a multi-hour gran fondo there is no reliable benefit. The reason is the share of anaerobic energy supply — the longer the effort, the smaller and less limiting the acidosis. Bicarbonate is therefore a tool for the middle-distance athlete, not the endurance athlete. How the body's energy systems are structured is explained in the training periodization guide.

Dose and timing: what matters

The dose used in studies is 0.2 to 0.3 grams of sodium bicarbonate per kilogram of body weight. For a 70-kilogram person that is 14 to 21 grams — roughly one to one and a half level tablespoons. Higher doses add little extra performance but clearly amplify the side effects. Do not go below 0.2 grams per kilogram, or the effect is lost.

Timing matters just as much: 60 to 180 minutes before the start. Bicarbonate needs this time to peak in the blood. The effect then lasts about two to three hours. Take it too early or too late and you miss the window — or you have already excreted the bicarbonate by the time you need it.

There are three common ways to take it:

• Powder in water: the cheapest option. About 500 to 750 millilitres of water for the daily dose, drunk in several portions over 15 to 30 minutes. The taste takes getting used to — salty and soapy.
• Capsules: enteric-coated capsules bypass the stomach and reduce discomfort — more expensive, but better tolerated, especially with a sensitive stomach.
• Ready-made sports products: pre-mixed bicarbonate drinks with flavourings. Convenient, but far more expensive than plain bicarbonate from the shop.

The stomach problems — the real sticking point

Bicarbonate is a base and reacts instantly in the acidic stomach: it foams, presses and irritates. Up to a third of users report nausea, stomach pressure, bloating or diarrhoea — and that is precisely why the supplement often rules itself out in practice. A bicarbonate-triggered stomach cramp costs more performance than the three percent it might deliver at best.

If you still want to try it, you can improve tolerance:

• Use a lower dose. Start at 0.2 grams per kilogram and work upwards — not everyone needs the full dose.
• Split it. Take the total in several small portions over one to two hours instead of one gulp.
• Take it with a meal. A carbohydrate-rich meal clearly buffers stomach irritation. Two to three hours before the start.
• Dilute with water. Plenty of fluid lowers the concentration in the stomach.
• Test in training. Never for the first time in a race. Build tolerance over several intense sessions.

Who benefits — and who does not

Athletes in short, high-intensity disciplines clearly can benefit: middle-distance runners, track cyclists, 100- and 200-metre swimmers, rowers and athletes in sports with many surges such as track cycling, sprinting or boxing. For very short efforts under a minute the benefit is also small — creatine is the better choice there.

For endurance athletes, bicarbonate is usually a non-issue. Anyone following a marathon training plan, riding a gran fondo or doing a half Ironman has a large aerobic share — acidosis is not the limiting factor. Spend the money on better fuelling instead: the topics marathon fueling and carb loading deliver far more than a bicarbonate experiment. And a 10-kilometre race, at roughly 40 minutes, sits only at the edge of the window — the benefit there is small to doubtful.

Bicarbonate and creatine: the combination

Newer studies examine whether bicarbonate together with other supplements does more than alone. The most plausible combination is bicarbonate plus creatine: creatine boosts short-term energy for sprints, bicarbonate buffers the acid produced. For efforts from 30 seconds to about three minutes the combination may have an extra effect. Beta-alanine and bicarbonate have also been studied together, with mixed results. For recreational athletes the combination is not a must — it only adds effort and side-effect risk.

Common mistakes with bicarbonate

• Using it in a marathon. The classic: athletes try bicarbonate before a long race and end up with stomach cramps and no performance gain. For efforts over ten minutes it does not belong in the plan.
• Dosing too high. More than 0.3 grams per kilogram adds no extra performance but plenty of discomfort.
• Taking it too late. Five minutes before the start it does not work — the active substance must already be in the blood.
• On an empty stomach with little water. This increases stomach irritation and the likelihood of diarrhoea.
• Confusing a training run with a race. Whether it works is tested in training at true race intensity — not in an easy jog, where the effect would not show anyway.

How Peakora plans your fuelling

Peakora does not hand out supplement advice off the cuff; it calculates from your race profile which fuelling matches your goal time. For the sessions where supplements really contribute, the fuelling calculator plans carbohydrates, fluid and sodium — and clearly classifies the effort: aerobic long run or anaerobic interval. So you know before the start whether bicarbonate even fits your race.

Frequently asked questions about bicarbonate in sport

Does baking soda actually help running performance?

Only for short, high-intensity efforts lasting roughly one to ten minutes. Meta-analyses show a performance gain of one to three percent for distances such as 800 to 5,000 metres. For marathon, half marathon or long rides there is no reliable benefit.

How much sodium bicarbonate should I take?

The effective dose is 0.2 to 0.3 grams of sodium bicarbonate per kilogram of body weight — for 70 kilograms, that is 14 to 21 grams. Higher doses add little benefit and mainly increase gastrointestinal discomfort. Always take it with plenty of water.

When should I take bicarbonate before a race?

60 to 180 minutes before the start. The effect kicks in once bicarbonate peaks in the blood and lasts about two to three hours. Test it first in several intense training sessions — never for the first time on race day.

What are the side effects of bicarbonate?

Mainly stomach pressure, nausea and diarrhoea — in up to a third of users. Countermeasures include a lower dose, splitting the total across several small portions over one to two hours, taking it with a carbohydrate-rich meal, or using enteric-coated capsules.