Sodium bicarbonate (baking soda) increases the blood’s buffering capacity and can help in short, very intense efforts. The catch is the stomach.
What is generally reported:
Typical doses are around 0.2-0.3 g/kg body mass, taken roughly 60-180 minutes before exercise
The best evidence is for efforts of about 1-7 minutes, or repeated sprints
Gastrointestinal distress (bloating, cramps, diarrhoea) is common and can wipe out any benefit
Newer strategies, such as splitting the dose, taking it with a carbohydrate meal, or using enteric-coated capsules, appear to reduce gut problems for some people
Worked example: a 70 kg athlete at 0.3 g/kg needs 21 g of sodium bicarbonate. That is a lot of baking soda, which is why taste and gut issues are so common.
Starting at the lower end (0.2 g/kg, about 14 g here) in training is a sensible way to test tolerance.