Influence of sodium bicarbonate ingestion on plasma ammonia accumulation during incremental exercise in man

Eur J Appl Physiol Occup Physiol. 1993;66(1):49-54. doi: 10.1007/BF00863399.


This investigation evaluated the influence of metabolic alkalosis on plasma ammonia (NH3) accumulation during incremental exercise. On two occasions separated by at least 6 days, six healthy men cycled at 70, 80, and 90% of maximum oxygen consumption (VO2max) for 5 min; each exercise period was followed by 5 min of seated recovery. Exercise was then performed at 100% VO2max until exhaustion. Beginning 3 h prior to exercise, subjects ingested 3.6 body mass-1 NaHCO3 (test, T) or 3.0 body mass-1 CaCO3 (placebo, P) (both equivalent to 0.3 over a 2-h period. Trials were performed after an overnight fast and the order of treatments was randomized. Arterialized venous blood samples for the determination of acid-base status, blood lactate and plasma NH3 concentrations were obtained at rest before treatment, 15 s prior to each exercise bout (Pre 70%, Pre 80%, Pre 90%, and Pre 100%), and at 0, 5 (5'Post), and 10 (10'Post) min after exhaustion. Additional samples for blood lactate and plasma NH3 determination were obtained immediately after each exercise bout (Post 70%, Post 80%, Post 90%) and at 15 min after exercise (15'Post). Time to exhaustion at 100% of VO2max was not significantly different between treatments [mean (SE): 173 (42) s and 184 (44) s for T and P respectively]. A significant treatment effect was observed for plasma pH with values being significantly higher on T than on P Pre 70% [7.461 (0.007) vs 7.398 (0.008)], Pre 90% [7.410 (0.010) vs 7.340 (0.016)], and 10'Post [7.317 (0.032) vs 7.242 (0.036)].(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Ammonia / blood*
  • Bicarbonates / pharmacology*
  • Exercise*
  • Humans
  • Male
  • Oxygen Consumption
  • Sodium / pharmacology*
  • Sodium Bicarbonate


  • Bicarbonates
  • Ammonia
  • Sodium Bicarbonate
  • Sodium