sodium bicarbonate

The positive impact of sodium bicarbonate on sprint performance has been confirmed by a new study comparing its effects with those of two other potential ‘buffering’ agents.

When continuous exercise is performed at high intensity for up to five minutes, energy production by anaerobic glycolysis is accompanied by a rise in intramuscular acidity that contributes to fatigue. Extracellular bicarbonate helps to buffer this acidity, thereby potentially delaying fatigue. And, indeed, ingestion of sodium bicarbonate has been shown to improve high-intensity performance substantially in previous studies.

The researchers (from the Netherlands, New Zealand and the UK) in the current study were keen to compare the effectiveness of sodium bicarbonate with sodium citrate and sodium lactate, which are known to produce indirect buffering effects.

In a double blind randomised crossover trial, 15 competitive male endurance runners, accustomed to brief intense efforts as part of their interval training, performed a run to exhaustion 90 minutes after ingestion of each of the agents and a placebo (sodium chloride) on separate days.

The mean run times to exhaustion were:

• bicarbonate 82.3 seconds;
• lactate 80.2s;
• citrate 78.2s;
• chloride 77.4s.

There were no substantial differences in gut discomfort between the buffer treatments.

The researchers conclude they have found ‘more evidence that ingestion of sodium bicarbonate is an effective strategy to enhance sprint performance. Sodium lactate is also likely to be effective, although possibly not as effective as sodium bicarbonate. Sodium citrate is probably not as effective as sodium bicarbonate.

‘We therefore recommend ingestion of sodium bicarbonate to enhance sprint performance.’

Med Sci Sports Exerc, vol 36, no 7, 1239-1243

Isabel Walker