Ingestion of agents that modify blood buffering action may affect high-intensity performance. Here we present a meta-analysis of the effects of acute ingestion of three such agents - sodium bicarbonate, sodium citrate and ammonium chloride - on performance and related physiological variables (blood bicarbonate, pH and lactate). A literature search yielded 59 useable studies with 188 observations of performance effects. To perform the mixed-model meta-analysis, all performance effects were converted into a percentage change in mean power and were weighted using standard errors derived from exact p-values, confidence limits (CLs) or estimated errors of measurement. The fixed effects in the meta-analytic model included the number of performance-test bouts (linear), test duration (log linear), blinding (yes/no), competitive status (athlete/nonathlete) and sex (male/female). Dose expressed as buffering mmoL/kg/body mass (BM) was included as a strictly proportional linear effect interacted with all effects except blinding. Probabilistic inferences were derived with reference to thresholds for small and moderate effects on performance of 0.5% and 1.5%, respectively. Publication bias was reduced by excluding study estimates with a standard error >2.7%. The remaining 38 studies and 137 estimates for sodium bicarbonate produced a possibly moderate performance enhancement of 1.7% (90% CL ± 2.0%) with a typical dose of 3.5 mmoL/kg/BM (∼0.3 g/kg/BM) in a single 1-minute sprint, following blinded consumption by male athletes. In the 16 studies and 45 estimates for sodium citrate, a typical dose of 1.5 mmoL/kg/BM (∼0.5 g/kg/BM) had an unclear effect on performance of 0.0% (±1.3%), while the five studies and six estimates for ammonium chloride produced a possibly moderate impairment of 1.6% (±1.9%) with a typical dose of 5.5 mmoL/kg/BM (∼0.3 g/kg/BM). Study and subject characteristics had the following modifying small effects on the enhancement of performance with sodium bicarbonate: an increase of 0.5% (±0.6%) with a 1 mmoL/kg/BM increase in dose; an increase of 0.6% (±0.4%) with five extra sprint bouts; a reduction of 0.6% (±0.9%) for each 10-fold increase in test duration (e.g. 1-10 minutes); reductions of 1.1% (±1.1%) with nonathletes and 0.7% (±1.4%) with females. Unexplained variation in effects between research settings was typically ±1.2%. The only noteworthy effects involving physiological variables were a small correlation between performance and pre-exercise increase in blood bicarbonate with sodium bicarbonate ingestion, and a very large correlation between the increase in blood bicarbonate and time between sodium citrate ingestion and exercise. The approximate equal and opposite effects of sodium bicarbonate and ammonium chloride are consistent with direct performance effects of pH, but sodium citrate appears to have some additional metabolic inhibitory effect. Important future research includes studies of sodium citrate ingestion several hours before exercise and quantification of gastrointestinal symptoms with sod...

The changes in pH and [HCO₃-] for the 8 NaHCO₃-ingestion protocols were similar, so an optimal protocol cannot be recommended. However, the results suggest that NaHCO₃ coingested with a high-carbohydrate meal should be taken 120-150 min before exercise to induce substantial blood alkalosis and reduce GI symptoms.

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This study aimed to assess nutritional intake, sports nutrition knowledge and risk of Low Energy Availability (LEA) in female Australian rules football players. Victorian Football League Women’s competition (VFLW) players (n = 30) aged 18–35 (weight: 64.5 kg ± 8.0; height: 168.2 cm ± 7.6) were recruited from Victoria, Australia. Nutritional intake was quantified on training days using the Automated 24 h Dietary Assessment Tool (ASA24-Australia), and sports nutrition knowledge was measured by the 88-item Sports Nutrition Knowledge Questionnaire (SNKQ). The risk of LEA was assessed using the Low Energy Availability in Females Questionnaire (LEAF-Q). Daily mean carbohydrate intake in the current investigation was 3 g⋅kg−1⋅d−1, therefore, below the minimum carbohydrate recommendation for moderate exercise of approximately one hour per day (5–7 g⋅kg−1⋅d−1) and for moderate to intense exercise for 1–3 h per day (6–10 g⋅kg−1⋅d−1) for 96.3% and 100% of players, respectively. Daily mean protein intake was 1.5 g⋅kg−1⋅d−1, therefore, consistent with recommendations (1.2–2.0 g⋅kg−1⋅d−1) for 77.8% of players. Daily mean calcium intake was 924.8 mg⋅d−1, therefore, below recommendations (1000 mg⋅d−1) for 65.5% of players, while mean iron intake was 12.2 mg⋅d−1, also below recommendations (18 mg⋅d−1) for 100% of players. Players answered 54.5% of SNKQ questions correctly, with the lowest scores observed in the section on supplements. Risk of LEA was evident in 30% of players, with no differences in carbohydrate (p = 0.238), protein (p = 0.296), fat (p = 0.490) or energy (p = 0.971) intakes between players at risk of LEA and those not at risk. The results suggest that female Australian rules football players have an inadequate intake of carbohydrate and calcium and low sports nutrition knowledge. Further investigation to assess the risk of LEA using direct measures is required.

Cocaine-dependent women, relative to their male counterparts, report shorter cocaine-free periods and report transiting faster from first use to entering treatment for addiction. Similarly, preclinical studies indicate that female rats, particularly those in the estrus phase of their reproductive cycle, show increased operant responding for cocaine under a wide variety of schedules. Making maladaptive choices is a component of drug dependence, and concurrent reinforcement schedules that examine cocaine choice offers an animal model of the conditions of human drug use; therefore, the examination of sex differences in decision-making may be critical to understanding why women display a more severe profile of cocaine addiction than men. Accordingly, we assessed sex and estrous cycle differences in choice between food (45 mg grain pellets) and intravenous cocaine (0.4 or 1.0 mg/kg per infusion) reinforcement in male, female (freely cycling), and ovariectomized (OVX) females treated with either estrogen benzoate (EB; 5 μg per day) or vehicle. At both cocaine doses, intact female rats choose cocaine over food significantly more than male rats. However, the estrous cycle did not impact the level of cocaine choice in intact females. Nevertheless, OVX females treated with vehicle exhibited a substantially lower cocaine choice compared with those receiving daily EB or to intact females. These results demonstrate that intact females have a greater preference for cocaine over food compared with males. Furthermore, this higher preference is estrogen-dependent, but does not vary across the female reproductive cycle, suggesting that ovarian hormones regulate cocaine choice. The present findings indicate that there is a biological predisposition for females to forgo food reinforcement to obtain cocaine reinforcement, which may substantially contribute to women experiencing a more severe profile of cocaine addiction than men.