Bicarbonate of soda and athletic performance: how soda loading works

Of all the things bicarbonate of soda gets credit for, this is the one with the strongest science behind it: taken before short, hard exercise, sodium bicarbonate is a recognised performance aid. Sports scientists call it "soda loading", and it has been studied for decades in sprinters, swimmers, rowers and combat athletes.

Why hard efforts burn

During high-intensity exercise your muscles produce energy faster than oxygen can arrive, and the by-products — hydrogen ions accompanying lactate — build up faster than your body can clear them. That rising acidity is a big part of the burning, heavy-legged feeling that forces you to slow down in the last lengths of a race or the final reps of a set.

What soda loading does

Sodium bicarbonate raises the buffering capacity of your blood. With more buffer available outside the muscle cells, hydrogen ions can be shuttled out and neutralised faster, which delays the point where acidity limits your effort. As the International Journal of Sport Nutrition and Exercise Metabolism puts it, bicarbonate ingestion "has been proposed to enhance performance by increasing extracellular buffering capacity". The American College of Sports Medicine lists it among the small group of supplements with genuine ergogenic evidence, and sports-science educators like Eric Trexler (Stronger By Science) and dietitian-strength coach Daniel Preiato point to the same conclusion: meaningful, repeatable benefits — for the right kind of effort.

Who actually benefits

The effect shows up in efforts of roughly one to seven minutes at high intensity — middle-distance running and swimming, rowing, track cycling, repeated sprints, hard interval sessions and combat sports. If your training is long and steady, bicarb has little to offer; acidity isn't what limits a slow hour on the road.

How athletes use it — and the golden rule

Research protocols typically use bicarbonate dissolved in water, taken one to three hours before the effort. The well-known catch is the gut: too much, too fast, or too close to the start causes stomach upset in some athletes. So the golden rule is: trial it in training first, never on race day. Start with a small dose, taken well before the session, with food and plenty of water, and build up only if your stomach is happy. The safety notes in our complete bicarbonate of soda guide apply here too — it's a sodium salt, and anyone with blood pressure, kidney or medication considerations should speak to a professional before loading.

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