Effects of sodium bicarbonate, caffeine, and their combination on repeated 200-m freestyle performance

Int J Sport Nutr Exerc Metab. 2008 Apr;18(2):116-30. doi: 10.1123/ijsnem.18.2.116.

Abstract

The purpose of this study was to investigate the effects of sodium bicarbonate (NaHCO(3)), caffeine, and their combination on repeated 200-m freestyle performance. Six elite male freestyle swimmers ingested NaHCO(3) (0.3 g/kg; B), caffeine (6.2 +/- 0.3 mg/kg; C), a combination of both (B+C), and placebo (P) on 4 separate occasions before completing 2 maximal 200-m freestyle time trials (TT1 and TT2) separated by 30 min. No significant differences (p = .06) were observed for performance in TT1 (B 2:03.01 +/- 0:03.68 min, C 2:02.42 +/- 0:03.17 min, B+C 2:01.69 +/- 0:03.19 min, P 2:03.77 +/- 0:03.21 min) or TT2 (B 2:02.62 +/- 0:04.16 min, C 2:03.90 +/- 0:03.58 min, B+C 2:01.70 +/- 0:02.84 min, P 2:04.22 +/- 0:03.75 min). The drop-off in performance time from TT1 to TT2, however, was significantly greater when C was ingested than with B (-1.5%, p = .002) or B+C (-1.2%, p = .024). This is likely because of the lower blood pH and slower recovery of blood HCO(3) post-TT1 after C ingestion. These findings suggest that the ergogenic benefit of taking C alone for repeated 200-m swimming performance appears limited. When combined with NaHCO(3), however, its negative impact on repeated maximal exercise performance is reversed.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Blood Chemical Analysis / methods*
  • Caffeine / metabolism
  • Caffeine / pharmacology*
  • Cross-Over Studies
  • Drug Combinations
  • Humans
  • Hydrogen-Ion Concentration
  • Lactates / blood
  • Male
  • Sodium Bicarbonate / metabolism
  • Sodium Bicarbonate / pharmacology*
  • Swimming / physiology*
  • Task Performance and Analysis*

Substances

  • Drug Combinations
  • Lactates
  • Caffeine
  • Sodium Bicarbonate