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Q & A - Using Bicarbonate To Buffer Lactic Acid In Athletes

Before I answer this question, let’s examine a few basics of human physiology and exercise performance. When you exercise by jogging, cycling, lifting weights, or playing any sport, your muscles produce waste and breakdown products. These products build up in your muscles, and one of the biggest waste products of exercise is lactic acid. Lactic acid build up in your muscles is what makes your muscles burn during sprints or when trying to complete that last repetition on the bench press. The type of exercise you perform also affects how quickly this lactic acid accumulates in your muscles. The more anaerobic the exercise, the faster the lactic acid levels climb in your muscles. A maximum effort weight training session or a 40 yard sprint workout tends to make lactic acid levels soar much faster than a slow five mile jog since the first two are much more anaerobic.

The body does have its own buffer system to prevent muscle pH from rising lactic acid and the muscle tissue becoming acidic. However, as a workout continues your body’s natural buffering system becomes unable to keep up with the acid levels. There are three main substances that buffer muscle cell tissue from rising pH levels and hydrogen ions: carnosine, phosphate, and bicarbonate (1). Interestingly, bicarbonate only accounts for less than ten percent of the body’s buffering potential. The body’s primary buffer in muscle tissue is carnosine with phosphate the secondary buffer (1).

Where sodium bicarbonate becomes more important to athletes in terms of buffering potential is in the blood. Exercise not only increases the acidity in your muscles but also acidifies your blood as well. When lactic acid levels rise in your blood, you get exercise-induced fatigue. The main buffer in the blood is sodium bicarbonate (2). This is how the idea came for athletes to ingest baking soda, otherwise known as sodium bicarbonate, to buffer their blood and muscles from acid. The concept was that by taking baking soda an athlete could train harder and longer because the added sodium bicarbonate would delay the rise in lactic acid levels.

The baking soda you eat or drink never makes it to your muscle tissue because it can’t make it through the muscle cell membranes, but it does make it into your blood stream (3). Because your body is always trying to reach a state of equilibrium, when your ingest the bicarbonate, it lowers your blood pH. This creates a gradient that brings the lactic acid out from the muscle tissue and into the blood stream, thereby lowering the pH of your muscle as well. Next, let’s examine how well this actually works on improving athletic endurance, performance, and time until exhaustion.

It has been well documented in the scientific literature that supplementing with bicarbonate does improve performance. One study gave athletes 200mg/kg bodyweight, about 18 grams for a 200 lb athlete. The athletes then performed five successive 60 second sprints on a stationary bike, with the last sprint lasting until the athlete reached exhaustion. The bicarbonate improved time until exhaustion by 42% (4). Another study gave athletes 300mg/kg which equals 27 grams for a 200 lb athlete. In this study college varsity track athletes ran an 800 meter sprint. The baking soda improved times by an average of 3 seconds or a distance of 19 meters. In elite runners such as these collegiate track athletes, cutting three seconds off your 800 time is a huge improvement (5). In rowers taking this same dose of 300mg/kg, the baking soda group rowed 50 meters further in a six-minute time trial over the placebo group (6). Most studies that have shown beneficial performance effects of supplementing with sodium bicarbonate have used high doses, over 200 mg/kg, and short high intensity exercise lasting less than six minutes.

What about side effects from taking baking soda before a workout? The most commonly reported side effect is intense gastrointestinal distress. Try this simple experiment in your kitchen. In a bowl add some baking soda, now pour some water or vinegar over the baking soda and watch what happens. This is what happens in your stomach, intestines, and colon. Over half of all athletes who took the baking soda developed severe diarrhea. Also, let’s not forget about the terrible taste of ingesting baking soda as well. In order to minimize the gastrointestinal side effects, athletes should divide the large dose into several smaller doses taken before a competition. One other side effect of the baking soda is the large amount of sodium that you are taking. A twenty-gram dose of baking soda contains five grams of sodium. This can cause havoc to one’s blood pressure.

In terms of the legality baking soda is not banned by the IOC, NFL, NBA, NHL, Major League Baseball, or NCAA. In summary, sodium bicarbonate is a cheap, legal supplement that has proven performance effects for short intense exercise lasting less than six minutes, but has some major problematic side effects. An athlete should not experiment with taking baking soda for the first time before a big competition or race. He or she should test how they tolerate taking baking soda in a practice. This way there are no additional surprises or games ruined by bathroom trips.

References

1. Lavender, G. & Bird, S.R. (1989). Effects of sodium bicarbonate ingestion upon repeated sprints. British Journal of Sports Medicine 23, pp. 41-45.

2. Johnson, W.R. & Black, D.H. (1953). Comparison of effects of certain blood alkalinizer and glucose upon competitive endurance. Journal of Applied Physiology 5, pp. 577-578.

3. Hood, V.L., Schubert, C., Keller, U., Muller, S. (1988). Effect of systemic pH on pHi and lactic acid generation in exhaustive forearm exercise. American Journal of Physiology 255 (24), pp. F479-F485.

4. Costill, D.L., et al. (1984). Acid base balance during repeated bouts of exercise. Influence of HC03. International Journal of Sports Medicine 5, pp. 225-231.

5. Wilkes, D., Gledhill, N. & Smith, R. (1983). Effect of induced metabolic alkalosis on 800-m racing time. Medicine and Science in Sports and Exercise 15 (4), pp. 277-280.

6. McNaughton, L.R. & Cedaro, R. (1991). The effect of sodium bicarbonate on rowing ergometer performance in elite rowers. The Australian Journal of Science and Medicine in Sport 23 (3), pp. 66-69.