Sodium Bicarbonate for Runners: What It Does, Dose and Avoiding Stomach Issues

Sodium bicarbonate for runners is a supplement with good scientific evidence but a very specific use: it improves performance in very intense efforts lasting a few minutes, not in a marathon. And it has a big practical drawback, because it can wreck your stomach if you don’t take it properly. In this guide I explain how it works, which runners it makes sense for, what dose is used, how to avoid stomach trouble and what precautions to take.

How sodium bicarbonate for runners works

When you run very fast, your muscles produce energy so quickly that hydrogen ions build up and the muscle becomes more acidic. That acidity is one of the causes of the burning feeling and of your legs not responding at the end of a hard interval.

Sodium bicarbonate, the same baking soda you have in your kitchen, acts as a buffer: it increases your blood’s ability to neutralize that acidity. That lets you hold the intensity a little longer before fatigue slows you down.

Which runners sodium bicarbonate makes sense for

The International Society of Sports Nutrition position stand on sodium bicarbonate concludes that it improves performance mainly in high-intensity efforts lasting from 30 seconds to about 10 minutes, and in repeated intervals. In running, that means the 800, 1,500, 3,000 or a very fast 5K, and hard interval sessions.

Over long distances like the half marathon or marathon, where the pace is aerobic, the benefit is small or none, and the risk of stomach problems isn’t worth it. For those races, there are supplements that make more sense, like caffeine for runners.

Sodium bicarbonate dose for runners

The most studied dose is 0.2 to 0.3 grams per kilo of body weight, taken 60 to 180 minutes before the effort. For a 70 kg person, that is 14 to 21 grams, which is quite a lot: several teaspoons.

Lower doses, around 0.2 g per kilo, usually give almost the same benefit with less discomfort, so it is a good idea to start there.

How to take sodium bicarbonate for runners without stomach problems

This is the big drawback: nausea, bloating, gas and diarrhea are common and can ruin a race. To reduce them, take the bicarbonate with a carb-rich meal and plenty of water, split it into several small doses over one or two hours, or use capsules, which are usually easier on the stomach than dissolved powder.

There are also protocols where a smaller dose is taken for several days before the event, which allows smaller doses on race day. Whatever your method, test it several times in interval sessions before using it in competition, just as you would with gels; I explain it in the guide on how to train your gut.

Precautions with sodium bicarbonate for runners

Sodium bicarbonate provides a lot of sodium: a full dose can be several times the recommended daily amount. If you have high blood pressure, kidney or heart problems, or follow a low-salt diet, talk to your doctor before taking it.

It isn’t banned by the World Anti-Doping Agency, so you can use it in competition. And remember it doesn’t replace training: it gives you a small extra margin in very specific efforts. To improve over those distances, what counts most is interval work and a good base.

Conclusion

Sodium bicarbonate for runners buffers muscle acidity and improves performance in intense efforts of 30 seconds to about 10 minutes, like the 800, 1,500 or hard intervals, but it barely helps in the half marathon or marathon. Use 0.2 to 0.3 g per kilo 1 to 3 hours before, take it with food and water or in capsules, test it in training and see your doctor if you have high blood pressure. Choose well, run better.

Frequently asked questions

What is sodium bicarbonate for in running?

It buffers the acidity that builds up in your muscles during very intense efforts, which lets you hold the intensity a bit longer. It is useful in short, intense races and intervals.

What dose of sodium bicarbonate for runners should I take?

0.2 to 0.3 grams per kilo of body weight, 60 to 180 minutes before the effort. Start with the lower dose.

Does sodium bicarbonate help in a marathon?

Hardly. In long, aerobic races the benefit is small and the risk of stomach trouble isn’t worth it.

How do I stop sodium bicarbonate upsetting my stomach?

Take it with a carb-rich meal and plenty of water, split it into small doses or use capsules, and test it in training first.

Is sodium bicarbonate allowed in competition?

Yes. It isn’t on the World Anti-Doping Agency’s prohibited list.