Effect of sodium citrate ingestion on oxygen debt & exercise endurance during supramaximal exercise.

ABSTRACT

BACKGROUND & OBJECTIVES: Administration of alkalinizing agents has been shown to improve performance in high intensity exercise. The present investigation was undertaken to determine whether sodium citrate ingestion enhances supramaximal endurance performance on a cycle ergometer and to assess its effect on oxygen debt incurred for the same supramaximal energy output. METHODS: Ten untrained, healthy, males performed acute intense bicycle ergometry exercise in two sessions viz., without (control) and with sodium citrate ingestion (experimental) in a dose of 0.5 g/kg body weight. Pre-exercise O2 consumption, pulse rate (PR) and respiratory rate (RR)/minute were recorded before both sessions. Exhaustion time (ET) was noted and work done calculated in the control session. Post-exercise PR and RR/min were also recorded in both sessions of study. Venous blood samples were drawn post-exercise and analysed for pH and lactate. O2 debt incurred was calculated in both sessions. RESULTS: Work output in supramaximal exercise averaged 69.40 +/- 15.31 Watts in the control session. None of the subjects in the experimental session complained of fatigue even when the exhaustion time noted in the control session was reached. Post-exercise tachycardia and tachypnoea were both significantly less (P<0.05 and P<0.001 respectively) in subjects after the experimental session as compared to the control. O2 debt incurred and lowering of blood pH were also significantly less (P<0.001) in the post-citrate phase. However, serum lactate increased significantly (P<0.05) in subjects after the experimental session. INTERPRETATION & CONCLUSION: Ingestion of sodium citrate prior to supramaximal exercise resulted in a reduction in post exercise O2 debt incurred. Blood pH was almost normal despite a higher serum lactate concentration. This probably led to an enhancement in exercise performance.