title: The effects of buffer ingestion on metabolic factors related to distance running performance.
abstract: We examined the effects of sodium bicarbonate (BIC) and sodium citrate (CIT) ingestion on distance running performance. Seven male runners [mean VO2max = 61.7 (SEM 1.7) ml.kg-1.min-1] performed three 30-min treadmill runs at the lactate threshold (LT) each followed by a run to exhaustion at 110% of LT. The runs were double-blind and randomly assigned from BIC (0.3 g.kg body mass-1), CIT (0.5 g.kg body mass-1) and placebo (PLC, wheat flour, 0.5 g.kg body mass-1). Venous blood samples were collected at 5, 15 and 25 min during the run and immediately post-exhaustion (POST-EX) and analysed for pH, and the concentrations of lactate ([la-]b) and bicarbonate ([HCO3-]). Performance was measured as running time to exhaustion at 110% of LT (TIME-EX). The pH was significantly higher (P < or = 0.05) for the BIC and CIT trials during exercise, but not POST-EX compared to PLC. The [la-]b was significantly higher (P < or = 0.05) for the CIT trial compared to PLC during exercise, and for both CIT and BIC compared to PLC at POST-EX. Blood [HCO3-] was significantly higher (P < or = 0.05) during exercise for BIC compared to PLC. TIME-EX was not significantly different among treatments: BIC 287 (SEM 47.4)s; CIT 172.8 (SEM 29.7)s; and PLC 222.3 (SEM 39.7)s. Despite the fact that buffer ingestion produced favourable metabolic conditions during 30 min of high intensity steady-state exercise, a significant improvement in the subsequent maximal exercise run to exhaustion did not occur.
authors.affiliation: Exercise Physiology Laboratory, University of Kansas 66045, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Potteiger
authors.forename: M J
authors.initials: MJ
authors.lastname: Webster
authors.forename: G L
authors.initials: GL
authors.lastname: Nickel
authors.forename: M D
authors.initials: MD
authors.lastname: Haub
authors.forename: R J
authors.initials: RJ
authors.lastname: Palmer
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D000863:Antacids / Q000494:pharmacology; D001639:Bicarbonates / Q000097:blood / Q000494:pharmacology; D001784:Blood Gas Analysis; D015992:Body Mass Index; D002021:Buffers; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D012420:Running
chemical_list: D000863:Antacids; D001639:Bicarbonates; D002021:Buffers; D019344:Lactic Acid