Racing flats? Check. Stopwatch? Check. Baking soda?
Written by: Matt Fitzgerald
There are various dietary supplements that are purported to enhance exercise performance by reducing lactic acid levels in the blood during exercise. Most such claims are based on outdated beliefs about the effects of lactic acid on exercise performance.
First of all, the muscles do not produce lactic acid during exercise. They produce a very similar substance called lactate. Until recently, it was believed that lactate produced by the muscles during exercise caused fatigue by making the muscles too acidic to function properly. However, it has been discovered that lactate does not contribute to rising muscle acidity during intense exercise. What’s more, increased muscle acidity is now known to be only a minor factor contributing to muscle fatigue.
This does not mean that all supplements affecting lactate metabolism and muscle acidity during exercise are non-performance-enhancing. While lactate is not among the acids that contribute to muscle fatigue, and while muscular acidosis is only a minor factor contributing to exercise fatigue, it’s still a factor, and there are supplements known to enhance exercise performance by slowing the decline in muscle pH balance that is normally seen during intense exercise. Let’s take a look at them.
Beta-alanine is a non-essential amino acid. In the body it is combined with another amino acid, histidine, to form a compound called carnosine, which buffers acids produced by the muscles during exercise. Studies on the effects of beta-alanine supplementation on exercise performance have produced mixed results, but some have shown increases in anaerobic capacity (or fatigue resistance at very high intensities). The beta-alanine dosage level that has been proven effective in studies is 3-6 grams daily. Most experts say 1 to 4 grams daily is plenty.
Best known as baking soda, sodium bicarbonate is also the most abundant acid buffer in muscle tissue. Sodium bicarbonate ingestion has been shown to improve performance in single-bout, high-intensity events, and in repeated sprint workouts, probably due to an increase in buffering capacity. Recommended dosage is 0.2-0.4 gram per kilogram of bodyweight before exercise. Possible side effects include nausea, vomiting and diarrhea, so be sure to try sodium bicarbonate preloading in training before you try it in a race.
Sodium citrate is a salt associated with citric acid. It occurs naturally in a variety of foods, including many fruits. It is also an intermediate product of aerobic metabolism in the human body. When consumed in food or produced in the body, sodium citrate quickly degrades into sodium bicarbonate. The most reliable results seem to follow when about 0.5 gram of sodium citrate per kilogram of body weight is dissolved into a liter of flavored water (it’s unpalatable in plain water) and consumed about 90 minutes before racing.
Sodium phosphate is mainly responsible for regulating acid-base balance in body tissues. It is also a major component of a compound that helps release oxygen from red blood cells. Scientists believe that, like sodium citrate, sodium phosphate plays a role in preventing muscular acidosis during very intense exercise. The sodium phosphate loading protocol that proved effective in boosting time trial performance in cyclists in one study was 1 gram taken four times per day for six days prior to racing.