Sodium bicarbonate, more commonly known as baking soda, has been used as a lactic acid buffer for a number of years. Strenuous exercise produces lactic acid, and supplementing with sodium
bicarbonate an hour or two before a workout can help reduce its accumulation. Here's the negative: To be effective, the necessary dosage is so large - 0.2-0.3 g/kg (that's about 20-30 grams
for a 200 pound bodybuilder) - that it can cause such side effects as nausea, vomiting, flatulence, diarrhea and muscle cramps. Hardly ideal conditions for training.
Rather than cause this kind of misery for yourself and others who happen to train near you, you might try calcium carbonate, the active ingredient in the calcium-rich versions of Turns and Rolaids. Calcium carbonate neutralizes twice as much acid as sodium bicarbonate, so you don't need nearly as much - about 10 grams should duplicate the acid-neutralizing effects of 20 grams of sodium bicarbonate. However, I've found that three to five grams or so of calcium carbonate produces beneficial effects. The only drawback is that it comes in chew-able tablets, so you have to chew up a mess of them to get the desired effect.
Notwithstanding chewing a mouthful of chalk, calcium carbonate has two advantages. First, it buffers the fall in serum pH (meaning that the blood will be less acidic) that would otherwise lead to the negative effects of excess lactic acid. Second, it does so without producing gastrointestinal distress commonly seen with the necessary amount of sodium bicarbonate. Offsetting gastrointestinal acidosis and serum acidosis is especially handy if you consume a high-carb supplement just prior to or during intense exercise.
Controlling / reducing lactic acid can have positive effects in your training, including improved performance and spared muscle protein. Too much lactic acid can cause the body to catabolize protein and amino acids, particularly glutamine.
If you are not training intensely, though, don't expect a bump after using calcium carb. Its greatest benefit is realized when you use a carb supplement in addition to intense training. If you are doing very high repetitions or driving yourself through an ass-kicking leg day, calcium carbonate coupled with carbs is something you may want to try.