Effects of various sodium bicarbonate loading protocols on the time-dependent extracellular buffering profile
Journal Title (Medline/Pubmed accepted abbreviation): J Strength Cond Res
Year: 2010
Volume: 24
Number: 9
Page numbers: 2551- 2557
doi (if applicable):

Summary of Background and Research Design

Background:Although much research has investigated the types of exercise that are enhanced with sodium bicarbonate (NaHCO3) ingestion, to date there has been limited research on the dosage and timing of ingestion that optimizes the associated ergogenic effects.

Hypothesis: Ingestion of NaHCO3 may attenuate metabolic alkalosis from exercise and enhance performance

Subjects: Male volunteers

Experimental design:Randomized, counter-balanced, single-blind study

Treatments and protocol: Part A, measures of alkalosis throughout 120 min after ingestion of various single NaHCO3 dosages and placebo (0.3 g/kg, 0.2 g/kg, 0.1 g/kg, and placebo); and
Part B, similar profiles after alternative NaHCO3 loading protocols (single morning dosage [SMD], single evening dosage [SED], and dosages ingested on 3 consecutive evenings [CED]). Within parts A and B, loading protocols were implemented in a randomized (counterbalanced), single-blind manner, with each test condition separated by 1 week. Blood pH, bicarbonate, and base excess were assessed at baseline and every 20 min post-ingestion up to 120 min post-ingestion.

Summary of research findings:
  • Blood buffering in the 0.1-g/kg condition was significantly lower than the 0.2-g/kg and 0.3-g/kg conditions (P < .002), but there was no significant differences between the 0.2-g/kg and 0.3-g/kg conditions (P = .34)
    • Although the blood buffering was relatively constant in the 0.1-g/kg and 0.2-g/kg conditions, it was significantly higher at 60 min than at 100 min and 120 min in the 0.3-g/kg condition (< .05)
  • Blood buffering for SMD was significantly higher than for SED and CED (P < .05)
  • Blood buffering in the SMD condition was significantly lower at 17:00 hours than at 11:00 hours (= .007)

Interpretation of findings/Key practice applications:

This article did not address actual performance effects of these increases in pH and it would have been interesting to see how blood pH would have been affected during exercise as opposed to rest. However, there are several studies demonstrating efficacy of bicarbonate loading for performance under certain exercise conditions. The single 0.2-g/kg and 0.3-g/kg NaHCO3 dosages appeared to be the most effective for increasing blood-buffering capacity. There was no significant difference between the 0.2-g/kg and 0.3-g/kg NaHCO3 dosages. The 0.2-g/kg dosage is best ingested 40 to 50 min before exercise and the 0.3-g/kg dosage 60 min before exercise. Because NaHCO3 loading may cause dehydration, it is important to monitor hydration by plasma/urine osmolality or the specific gravity of urine. Single doses exceeding 0.3 g/kg are not recommended because the risk of side effects increases.
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