The purpose of this study was to determine the effects of the simultaneous use of pyridoxine‐alpha‐ketoglutarate (PAK) and sodium bicarbonate (NaHCO3) on short‐term maximal exercise capacity in eight well‐trained male cyclists. The study consisted of the determination of maximal power output and the administration of various combinations of placebos, PAK and NaHCO3, followed by a short‐term maximal exercise test.

To determine maximal power output (powermax), the subjects performed a continuous, incremental test on a Monark bicycle ergometer to symptom limited maximum (test 1). To determine the effects of NaHCO3 and PAK on short‐term maximal exercise performance, the subjects were administered either placebo (PLA), PAK and sodium bicarbonate (P/B), PAK and placebo (PAK), or sodium bicarbonate and placebo (BIC) prior to performing short‐term maximal exercise (test 2). Oral tablets of NaHCO3 and PAK were given in doses of 260 mg kg‐1and 50 mg kg‐1 respectively. The subjects pedalled at the power output corresponding to 100% of their VO2 max at 70 rev min‐1 until voluntary cessation or until they were unable to maintain pedal revolution rate. Venous blood samples were drawn at rest (RES), cessation of exercise (CES) and after 2 min of recovery (REC) and analysed for lactate, pH and bicarbonate ion concentration.

The subjects attained an average maximum power output of 377±20 W during the graded maximal pre‐test (test 1). There were no significant differences between treatments in the ability to sustain powermax during test 2. During test 2, the subjects were able to sustain powermax for 7.6±4.3 min with P/B, 6.7±2.9 min with PAK, 7.3±4.9 min with BIC and 6.9±2.7 min with placebo (mean±s.E.).

Blood lactate (BLa) was significantly elevated at cessation of exercise and remained elevated during recovery, but there were no significant differences between treatments. Bicarbonate fell significantly during exercise and recovery in each treatment. At rest, bicarbonate levels were significantly higher in both the P/B and BIC than in the PAK or PLA treatments. Pooled data from the P/B and BIC treatments demonstrated a significant increase in pH at rest and end of exercise when compared to PLA treatment. These data suggest that sodium bicarbonate rather than PAK was responsible for this increase.

In summary, our data suggest that in the dosages used in this study, administration of sodium bicarbonate or PAK, alone or in combination, is ineffective in increasing short‐term maximal exercise capacity.