title: Effect of sodium bicarbonate on [HCO3-], pH, and gastrointestinal symptoms.
abstract: BACKGROUND
  Sodium bicarbonate (NaHCO₃) is often ingested at a dose of 0.3 g/kg body mass (BM), but ingestion protocols are inconsistent in terms of using solution or capsules, ingestion period, combining NaHCO₃ with sodium citrate (Na₃C₆H₅O₇), and coingested food and fluid.
  
  
  OBJECTIVE
  To quantify the effect of ingesting 0.3 g/kg NaHCO₃ on blood pH, [HCO₃-], and gastrointestinal (GI) symptoms over the subsequent 3 hr using a range of ingestion protocols and, thus, to determine an optimal protocol.
  
  
  METHODS
  In a crossover design, 13 physically active subjects undertook 8 NaHCO₃ experimental ingestion protocols and 1 placebo protocol. Capillary blood was taken every 30 min and analyzed for pH and [HCO₃-]. GI symptoms were quantified every 30 min via questionnaire. Statistics used were pairwise comparisons between protocols; differences were interpreted in relation to smallest worthwhile changes for each variable. A likelihood of >75% was a substantial change.
  
  
  RESULTS
  [HCO₃-] and pH were substantially greater than in placebo for all other ingestion protocols at almost all time points. When NaHCO3 was coingested with food, the greatest [HCO₃-] (30.9 mmol/kg) and pH (7.49) and lowest incidence of GI symptoms were observed. The greatest incidence of GI side effects was observed 90 min after ingestion of 0.3 g/kg NaHCO₃ solution.
  
  
  CONCLUSIONS
  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.
authors: Physiology Dept., Australian Institute of Sport, Canberra, Australia.
authors: Amelia J
authors: AJ
authors: Carr
authors: Gary J
authors: GJ
authors: Slater
authors: Christopher J
authors: CJ
authors: Gore
authors: Brian
authors: B
authors: Dawson
authors: Louise M
authors: LM
authors: Burke
mesh_terms: D000328:Adult; D002951:Citrates / Q000097:blood / Q000494:pharmacology; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004334:Drug Administration Schedule; D004435:Eating; D005260:Female; D005767:Gastrointestinal Diseases / Q000139:chemically induced / Q000517:prevention & control*; D041981:Gastrointestinal Tract / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D017693:Sodium Bicarbonate / Q000009:adverse effects / Q000097:blood* / Q000494:pharmacology*; D000077559:Sodium Citrate; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D002951:Citrates; D004040:Dietary Carbohydrates; D000077559:Sodium Citrate; D017693:Sodium Bicarbonate