Increased Blood pH but Not Performance with Sodium Bicarbonate Supplementation in Elite Rugby Union Players
International Journal of Sport Nutrition & Exercise Metabolism
Purpose: This study investigated the effect of ingesting 0.3 g/kg body weight (BW) of sodium bicarbonate (NaHCO 3 ) on physiological responses, gastrointestinal (GI) tolerability, and sprint performance in elite rugby union players. Methods: Twenty-five male rugby players, age 21.6 (2.6) yr, participated in a randomized, double-blind, placebo-controlled crossover trial. Sixty-five minutes after consuming 0.3 g/kg BW of either NaHCO 3 or placebo, participants completed a 25-min warm-up followed
... n warm-up followed by 9 min of high-intensity rugby-specific training followed by a rugby-specific repeated-sprint test (RSRST). Whole-blood samples were collected to determine lactate and bicarbonate concentrations and pH at baseline, after supplement ingestion, and immediately after the RSRST. Acute GI discomfort was assessed by questionnaire throughout the trials, and chronic GI discomfort was assessed during the 24 hr postingestion. Results: After supplement ingestion and immediately after the RSRST, blood HCO 3 concentration and pH were higher for the NaHCO 3 condition than for the placebo condition (p < .001). After the RSRST, blood lactate concentrations were significantly higher for the NaHCO 3 than for the placebo condition (p < .001). There was no difference in performance on the RSRST between the 2 conditions. The incidence of belching, stomachache, diarrhea, stomach bloating, and nausea was higher after ingestion of NaHCO 3 than with placebo (all p < .050). The severity of stomach cramps, belching, stomachache, bowel urgency, diarrhea, vomiting, stomach bloating, and flatulence was rated worse after ingestion of NaHCO 3 than with placebo (p < .050). Conclusions: NaHCO 3 supplementation increased blood HCO 3 concentration and attenuated the decline in blood pH compared with placebo during high-intensity exercise in well-trained rugby players but did not significantly improve exercise performance. The higher incidence and greater severity of GI symptoms after ingestion of NaHCO 3 may negatively affect physical performance, and the authors strongly recommend testing this supplement during training before use in competitive situations.