Baking soda can act as a buffer for lactic acid. With less lactic acid buildup in the muscle, theoretically you should be able to perform more reps.
With less lactic acid you also do not experience as much pain in the muscle during a set, allowing you to dig deeper into extreme training. This
trick is not new. It has been used by athletes - especially endurance athletes - for decades. When Dr. Mauro Di Pasquale came out with his high-fat
diet, he recommended a Kool-Aid / baking soda drink that was to be sipped throughout the workout. Mauro chose Kool-Aid because it is cheap and
contains a lot of sugar, but you could also mix baking soda with any good commercial carb drink or sports drink.
Does it work? Yes, a little. I experimented with Mauro's baking soda drink and found that it did reduce pain in the muscle and that I could do more reps during a set. The downside is that baking soda tastes very salty. Even if you mix it with a beverage full of sugar, the drink still tastes salty. This means you could feel thirsty after you take a swig. I found that I needed two containers during training, one with the baking soda mixture and a bottle with just cold water. The good thing is that you definitely stay hydrated because you have to drink the entire baking soda drink to get the proper buffering effect, and you drink another bottle of water to wash the salty taste out of your mouth.
The buffering effect does happen, but baking soda docs not perform miracles. We're talking about one or two more reps a set and maybe about 10 percent less burn in the muscle. That makes a difference, but it doesn't totally eliminate the pain of muscle exertion (dream on). It's not for everyone but it's worth trying if you find getting those last few reps a problem. Oh, and try holding your nose as you sip! A method I have used and got better results from is to go to a pharmacy and buy some gelatin capsules. Take the required amount of baking soda (two table spoons) and stuff it in the capsules. Take the desired amount 1 hour before training (as it must be absorbed into the blood before it can buffer lactic acid). Try this method and see what happens, best of luck