High doses of sodium bicarbonate increase lactate levels and delay exhaustion in a cycling performance test

It is well established that ingestion of sodium bicarbonate (NaHCO₃) causes metabolic alkalosis. However, there is no consensus in terms of optimal NaHCO₃ doses leading to enhanced performance. This study aimed to determine the effects of different NaHCO₃ doses on performance and lactate clearance in non-professional cyclists.

Twenty-one cyclists performed the following three double-blind trials: 1) ingestion of 0.3 g · kg^-1 body weight (BW) of placebo; 2) ingestion of 0.1 g · kg^-1 BW NaHCO₃ plus 0.2 g · kg^-1 BW placebo (0.1 BC); and 3) ingestion of 0.3 g · kg^-1 BW NaHCO₃ (0.3 BC). Performance was evaluated after warm-up on the bike followed by a performance test until exhaustion. Lactate levels were monitored in blood samples before and immediately after performance tests.

Lactate levels in the blood were significantly higher after exercise in 0.3 BC and 0.1 BC (15.12 ± 0.92 versus 10.3 ± 1.22 and 13.24 ± 0.87 versus 10.3 ± 1.22 mmol/L; P < 0.05) compared with control. Significant improvements in performance were only identified in 0.3 BC group (76.42 ± 2.14; P = 0.01).

The present study found that 0.3 g · kg^-1 BW NaHCO₃ is effective in improving performance and improving blood lactate levels in cyclists compared with control and 0.1 g · kg^-1 BW NaHCO_3.