Sodium bicarbonate, the same stuff sold as baking soda, works as a buffer in the body. It helps neutralize excess acid, whether that acid comes from a meal or from hard exercise. That simple chemistry is the reason people reach for it as an antacid and as a pre-workout aid.
For heartburn or indigestion, a glass of water with a small dose after a meal calms the burn. Athletes take a larger dose dissolved in water about 60 to 120 minutes before sprinting, lifting, or any effort that floods the muscles with acid. The buffering action eases that burn, delays fatigue, and speeds recovery between bouts of work.
Watch the dose and your own tolerance. This is a sodium-heavy compound, so anyone managing blood pressure or on a low-sodium diet should steer clear. Some kidney conditions also make it a bad choice. Too much, especially on a full stomach, can cause gas, bloating, and serious upset. Rarely, heavy overuse can push blood pH into dangerous territory. Check with a doctor before adding it to a routine, especially if you take other medications.