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Study type: OtherConfidence: LowChecked against the abstract

Effect of sodium bicarbonate on [HCO3-], pH, and gastrointestinal symptoms: eight ingestion protocols compared (crossover)

Carr AJ, Slater GJ, Gore CJ, Dawson B, Burke LM

Year2011
Sample sizen=13
JournalInternational Journal of Sport Nutrition and Exercise Metabolism
AuthorsCarr AJ, Slater GJ, Gore CJ, Dawson B, Burke LM

Evidence is still limited and needs further study

Summary

Summary

A crossover trial in which 13 physically active subjects undertook eight ingestion protocols using 0.3 g per kg of body mass of sodium bicarbonate, plus one placebo protocol. Capillary blood was taken every 30 minutes over the following three hours for pH and [HCO3-], and gastrointestinal symptoms were quantified by questionnaire. [HCO3-] and pH were substantially greater than placebo for every protocol at almost all time points. When it was coingested with food, [HCO3-] (30.9 mmol/kg) and pH (7.49) were greatest and the incidence of gastrointestinal symptoms was lowest; the greatest incidence was observed 90 minutes after ingesting 0.3 g/kg as a solution. The authors conclude that because the changes in pH and [HCO3-] were similar across the eight protocols, an optimal protocol cannot be recommended. They add that their results suggest sodium bicarbonate coingested with a high-carbohydrate meal should be taken 120-150 minutes before exercise to induce substantial blood alkalosis and reduce gastrointestinal symptoms. Note that the abstract prints the unit for [HCO3-] as mmol/kg. We have not been able to consult the full text, and we cannot verify whether that unit is correct, so we quote the abstract as printed.

Source (read the original)

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DOI: 10.1123/ijsnem.21.3.189

Verification breakdown

Bibliography
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Content
The text of this record has been checked against the original abstractWhat was checked: sample size, measured outcomes, study design, population studiedCreated against the abstract. The participants were 13 physically active subjects rather than athletes specifically, and performance was not measured. That the authors themselves decline to recommend an optimal protocol must not be dropped. The studyType is other because the abstract does not state that the study was randomised. The abstract prints the unit for [HCO3-] as mmol/kg. Unable to consult the full text, we cannot verify the unit and quote the abstract as printed.
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Bibliographic checks are made by querying Crossref and PubMed. The result reflects the check date shown above; retractions or corrections issued since then are not included. A new build using a lock older than 365 days will fail. Content checks are made by AI matching the record against the original abstract; they are not expert judgements of validity. What has not been checked is shown rather than hidden. About our verification process

Key Findings

Key findings

  • 1

    When coingested with food, [HCO3-] (30.9 mmol/kg) and pH (7.49) were greatest and the incidence of gastrointestinal symptoms was lowest. Note that the abstract prints the unit for [HCO3-] as mmol/kg. We have not been able to consult the full text, and we cannot verify whether that unit is correct, so we quote the abstract as printed.

  • 2

    The greatest incidence of gastrointestinal side effects was observed 90 minutes after ingesting 0.3 g/kg as a solution.

  • 3

    The authors conclude that because the changes in pH and [HCO3-] were similar across the eight protocols, an optimal protocol cannot be recommended.

  • 4

    The suggestion to take it 120-150 minutes before exercise with a high-carbohydrate meal is offered as an implication of the results.

  • 5

    The participants were 13 physically active subjects, and performance was not measured. Statistics were pairwise comparisons between protocols interpreted against the smallest worthwhile change for each variable, with a likelihood above 75% treated as a substantial change.

Related Research

Related research

Meta-analysis

Effects of acute alkalosis and acidosis on performance: a meta-analysis

Sports Medicine, 2011

A meta-analysis pooling the effects of three agents that modify blood buffering — sodium bicarbonate, sodium citrate and ammonium chloride — on exercise performance. It covers 59 studies and 188 performance effects, all converted into a percentage change in mean power. For sodium bicarbonate, 38 studies and 137 estimates produced a possibly moderate enhancement of 1.7% (90% confidence limits ±2.0%) at a typical dose of about 3.5 mmol per kg of body mass (about 0.3 g/kg) in a single one-minute sprint by male athletes. Those limits cross zero. The modifying effects of study and subject characteristics are all reported as small, with their 90% confidence limits: +0.5% (±0.6%) per 1 mmol/kg increase in dose; +0.6% (±0.4%) with five extra sprint bouts; −0.6% (±0.9%) for each tenfold increase in test duration (for example 1 to 10 minutes); −1.1% (±1.1%) with non-athletes; −0.7% (±1.4%) with females. Four of these five — all but the bouts estimate — have limits crossing zero and should be read only as indications of direction. Unexplained variation between research settings was typically ±1.2%. Sodium citrate had an unclear effect (0.0%, ±1.3%), and ammonium chloride a possibly moderate impairment of 1.6% (±1.9%). The authors recommend ingestion of 0.3-0.5 g/kg of body mass and list quantification of gastrointestinal symptoms with sodium bicarbonate and citrate as important future research.

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