Effects of Phosphate Loading on Metabolic and Myocardial Responses to Maximal and Endurance Exercise

Abstract

Six trained male cyclists and triathletes participated in a double blind study to determine the effects of phosphate loading on maximal and endurance exercise performance. Subjects ingested either 1 gm of tribasic sodium phosphate or a glucose placebo four times daily for 3 days prior to performing either an incremental maximal cycling test or a simulated 40-km time trial on a computerized race simulator. They continued the supplementation protocol for an additional day and then performed the remaining maximal or performance exercise test. Subjects observed a 17-day washout period between testing sessions and repeated the experiment with the alternate supplement regimen in identical fashion. Metabolic data were collected at 15-sec intervals while venous blood samples and 2D-echocardiographic data were collected during each stage of exercise during the maximal exercise test and at 8-km intervals during the 404cm time trial. Results indicate that phosphate loading attenuated anaerobic threshold, increased myocardial ejection fraction and fractional shortening, increased maximal oxidative capacity, and enhanced endurance performance in competitive cyclists and triathletes.

The Influence of Sodium Phosphate Supplementation on VO2max, Serum 2,3-diphosphoglycerate Level and Heart Rate in Off-road Cyclists

“…In a similar experiment Kreider et al (1992) also showed a significant (17%) increase in serum phosphate concentration following supplementation and 9% higher values of VO2max, yet they did not evaluate 2,3-DPG concentration. Bradle et al (1988) despite a significant (p<0,05) rise in the concentration of phosphates in the blood (35%) following 4 day of calcium phosphate intake, registered no changes in 2,3-DPG, P50, pH and VO2max.…”

Effects of sodium phosphate and beetroot juice supplementation on repeated-sprint ability in females

“…Furthermore, best sprints were 0.13-0.23 and 0.15-0.20 s faster (~6 % improvement; p < 0.01) after SP compared with placebo and BJ, respectively, for all sets (d = −0.54 to −0.89). While some studies have found no benefit of SP on exercise performance (Brennan and Connolly 2001;Buck et al 2014;Brewer et al 2014;West et al 2012), others have reported improved endurance exercise performance (Folland et al 2008;Kreider et al 1992) and aerobic capacity of 3.5-12 % (Brewer et al 2013;Cade et al 1984;Czuba et al 2008Czuba et al , 2009Kreider et al 1990Kreider et al , 1992Stewart et al 1990) following 3.6-4 g or 50 mg kg −1 of fat free mass (FFM) of SP ingested each day over a 3-to 6-day loading period. Furthermore, Brewer et al (2014) recently reported improved sprinting and time-trial efforts whilst cycling following SP loading.…”

Scientific Opinion on the substantiation of health claims related to sodium phosphate and increase in endurance performance (ID 318, 2887) and increase in endurance capacity (ID 318, 2887) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

“…While all four of these studies assessed the effects of the intervention on maximal oxygen uptake (VO 2 max), only three were considered pertinent for the respective claims considered in this opinion; these were the two which assessed changes in endurance performance (Kreider et al, 1990;Kreider et al, 1992), and the one which assessed changes in endurance capacity (Stewart et al, 1990). …”

“…The four references provided for the scientific substantiation of the claims reported on human intervention studies on the effects of (tribasic) sodium phosphate consumption in athletes performing endurance exercise (Cade et al, 1984;Kreider et al, 1990;Kreider et al, 1992;Stewart et al, 1990). While all four of these studies assessed the effects of the intervention on maximal oxygen uptake (VO 2 max), only three were considered pertinent for the respective claims considered in this opinion; these were the two which assessed changes in endurance performance (Kreider et al, 1990;Kreider et al, 1992), and the one which assessed changes in endurance capacity (Stewart et al, 1990).…”

“…In a randomised, cross-over, double-blind, placebo-controlled intervention study (Kreider et al, 1992), six trained male cyclists and triathletes participated in assessing the effects of phosphate loading on maximal and endurance exercise performance. Subjects consumed either 1 g of tribasic sodium phosphate or placebo (glucose) four times daily for three days prior to performing either an incremental maximal cycling test or a simulated 40 km time trial on a computerised race simulator.…”