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Brennan, K M.1; Connolly, D A. J. FACSM1

Medicine & Science in Sports & Exercise: May 2001 - Volume 33 - Issue 5 - p S165
D16n Free Communication/Poster Nutrition and Sport

1Human Performance Lab, University of Vermont, Burlington, VT

(Sponsor: Declan Connolly, FACSM)

The use of sodium phosphate (NaPO4) supplementation to improve endurance performance has long been proposed without substantial evidence. There are several investigations of NaPO4 supplementation in the literature, however the findings are equivocal. Phosphate loading has been proposed to alter metabolic and cardiovascular functions including; an attenuated lactate threshold, an increased availability of inorganic phosphate for creatine phosphate synthesis, enhanced myocardial and cardiovascular efficiency, and an improved aerobic capacity. To test theory that NaPO4 could improve aerobic performance the current study was undertaken. 12 previously trained male subjects (Mean VO2 max 60.6 ± 4.4 mlkg−1min−1) participated in a double blind crossover experiment to determine the effects of a commercial sodium phosphate supplement on maximal oxygen consumption (VO2 max) and blood lactate. Subjects performed an incremental VO2 max test on a cycle ergometer using 3-minute stages. Lactate concentrations were determined from fingerstick blood samples at the end of each stage and immediately analyzed as whole blood. After the completion of pre-supplement testing, subjects were randomly assigned either a sodium phosphate or a placebo supplement. The supplementation regimen consisted of 1000mg of either dibasic sodium phosphate or placebo four times a day for 4 days. On day 5 subjects returned to the lab to repeat the testing protocol. Repeated measures analysis of variance (P < 0.05) indicated no significant effects of sodium phosphate supplementation in contrast to the placebo treatment for VO2 max or blood lactate. In conclusion, our data suggest that NaPO4 is an ineffective supplement when used to enhance endurance performance.

©2001The American College of Sports Medicine