What this Trial Is About

Sodium bicarbonate (SB) is one of the ergogenic aids that enhance short-duration, high-intensity sports performance by improving the buffering system. However, studies suggest that SB may also be beneficial for prolonged high-intensity endurance exercises, where anaerobic glycolysis plays a role. The commonly used SB dose in these studies (0.3 g/kg) often leads to gastrointestinal (GI) discomfort, necessitating alternative approaches. Among various protocols, consuming SB with a carbohydrate-rich meal has been identified as an effective strategy to mitigate GI distress. Although some studies indicate a positive effect of SB on performance, research involving female athletes remains limited, comprising only 7.4% of the total studies. Given that women generally have lower muscle mass and fewer type II muscle fibers, their glycolytic capacity might be lower, and SB could have distinct physiological effects on them. While SB has been shown to enhance anaerobic performance in female athletes, its impact on high-intensity endurance exercise performance has not yet been investigated. This study aims to examine the effects of acute sodium bicarbonate ingestion, consumed with a carbohydrate-rich meal, on prolonged high-intensity running performance, acid-base balance, and GI response in female runners. In this double-blind, crossover-designed study, 19 recreational female runners will be randomly assigned to either a bicarbonate or a placebo group. The bicarbonate group will ingest 0.3 g/kg SB, while the placebo group will consume 0.03 g/kg salt, both 90 minutes before exercise, alongside a carbohydrate-rich meal. Participants will then complete a 10 km time-trial run, aiming for their best performance. Throughout the study, GI symptoms, exercise completion time, blood lactate, pH, bicarbonate levels, heart rate, and perceived exertion during exercise will be assessed. Performance tests will be conducted twice during the follicular phase of the menstrual cycle, with a 3-7 days washout period between trials. A two-way repeated measures ANOVA will be used to compare the effects of the interventions.

Sodium Bicarbonate Intake on Endurance Performance