Rossi, A., Hawkins, S., Cornwell, A., DiCaprio, P., Chou, C.-Y., & Khodiguian, N. (2006). The effects of modified chronic sodium bicarbonate ingestion on short-duration, high-intensity performance in elite middle-distance runners. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2237.

This study determined the efficacy of a modified chronic sodium bicarbonate ingestion protocol that may increase blood bicarbonate more than previous methods without causing gastro-intestinal distress. Elite middle-distance runners (M = 4; F = 2) ingested four progressively larger doses (600 mg/kgBW) of either CaCO3 (placebo) or NaHCO3 (modified chronic sodium bicarbonate) during the 24 hours prior to performance trials, or an acute dose of NaHCO3 (300 mg/kg) 90 minutes pre-performance. Each performance trial consisted of a run to exhaustion at approximately 1,500m running race intensity (110% VO2max) on an inclined (8%) treadmill. Pre-ingestion, pre-exercise, and post-exercise blood plasma was analyzed for sodium, lactate, and bicarbonate concentrations, hematocrit, and pH.

The modified chronic ingestion protocol led to significantly higher pre-exercise plasma bicarbonate concentration than the acute and placebo trials. It resulted in less gastro-intestinal distress. No significant differences in time to exhaustion were observed between groups. Plasma lactate increased approximately 11-fold post-exercise in all groups, but there were no significant differences between groups in absolute decrease in bicarbonate concentration or CO2 exhalation during exercise. Chronic sodium bicarbonate ingestion also led to a significant decrease in hematocrit and a significant increase in body weight.

Implication. Bicarbonate ingestion did not improve performance. The modified chronic sodium bicarbonate ingestion protocol administered in the current study elevated plasma bicarbonate concentration more than typical acute ingestion, and was better tolerated. Increasing plasma bicarbonate concentration above normal levels may not have an ergogenic effect on competitive middle-distance running.

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