Introductory remarks

The biochemistry of exercise-induced metabolic acidosis has been of considerable interest for many years. We now accept that the fatigue associated with high rates of anaerobic glycolysis is caused not by the accumulation of lactate but by the imbalance between the rate of proton release and the rate of proton buffering and removal.

It is 70 years since formal investigations into acid–base balance and exercise began. Some carefully controlled studies in the 1980s suggested that ingestion of sodium bicarbonate (NaHCO₃) could be effective in enhancing the performance of events such as an 800 m track run, via an improved capacity to buffer metabolic acidosis which then reduced or delayed the onset of the accompanying fatigue This topic remains of considerable interest with regular additions to the literature.

The authors of the following brief reviews have a long history of involvement in investigating the ergogenic effects of buffers on athletes.

Sodium bicarbonate and sodium citrate

L R McNaughton

Introduction

Athletes utilise many different strategies to enhance performance. Among the more popular ergogenic aids are sodium bicarbonate (NaHCO₃) or sodium citrate, collectively recognised as “buffers.” These substances, permitted for use by the World Anti-Doping Agency code, potentially provide the body with improved resistance to the fatigue caused by changes in acid–base balance.

Typically, resting human arterial blood pH is approximately pH 7.4, slightly alkalotic, but after strenuous exercise may fall to ∼7.1, while muscle pH decreases to ∼6.8. Buffers such as NaHCO₃ and sodium citrate will increase the buffering capacity by increasing, for example, the amount of bicarbonate that can be utilised, say, by increasing the pH to 7.5.

Studies in the 1980s on intense running using NaHCO₃ as a buffer1 …