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Buffer zone

[This article originally appeared in the October 2003 issue of Runner's World magazine.]

Q. I heard that taking Tums before a race can improve my performance. Is this true?
--A.E., Biloxi, Miss.

A.Your question is based on the theory that lactic acid causes fatigue and that counteracting the lactic acid should therefore delay fatigue and enhance performance. Many (though not all) exercise scientists accept this theory as valid for events lasting from two minutes to an hour or more. Supporting evidence comes in part from numerous studies (Matson & Tran, International Journal of Sport Nutrition 3: 2-28, 1993; McNaughton et al., European Journal of Applied Physiology 80: 64-9, 1999) in which runners or cyclists have improved their times by ingesting buffers (substances that prevent the blood from becoming too acidic). Before you raid the shelves of your local pharmacy, though, you should consider the following caveats.

First, not all buffers produce the desired effect. For example, eating sodium bicarbonate (the active ingredient in Alka-Seltzer and baking soda) will make your blood less acidic, but eating calcium carbonate (the active ingredient in Tums and Rolaids) will not (Matson & Tran, International Journal of Sport Nutrition 3: 2-28, 1993; Stephens et al., Medicine and Science in Sports and Exercise 34: 614-21, 2002). Second, a lot of buffer must be consumed; the dose used in most studies is about 0.14 grams of sodium bicarbonate per pound of body weight (Horswill, International Journal of Sport Nutrition 5: S111-9, 1995). To take in that amount, a 150-pound person would have to choke down 10 or so Alka-Seltzer tablets (dissolved in water) prior to racing -- not a good idea unless you have medical supervision (especially since some forms of Alka-Seltzer have extra ingredients such as aspirin). Finally, not only do some people not seem to benefit from bicarbonate loading, some actually experience stomach discomfort and/or diarrhea as a result of it.

Clearly, the pre-race buffer breakfast is not for everyone. If you do want to try it, my recommendations would be to (1) use sodium bicarbonate rather than some other less proven buffer, (2) ingest the buffer slowly over a period of an hour or so, finishing at least one hour before your run (Linderman & Fahey, Sports Medicine 11: 71-7, 19991), and (3) seek help from a health care professional in finding a dosage that is both safe and effective.

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