What is Sodium Phosphate?
Phosphate is a compound with numerous biological roles.
Proposed Benefits of Sodium Phosphate
Phosphate supplementation is used to enhance athletic performance by improving oxygen offloading from haemoglobin.
Mechanism of Action of Sodium Phosphate
Phosphate supplementation is proposed to enhance athletic performance by increasing red blood cell 2, 3-bisphosphoglycerate levels and hence improve oxygen offloading from haemoglobin.
Research on Sodium Phosphate
The research findings indicating the performance benefits of phosphate supplementation are inconsistent. There is also a lack of data showing an increase in 2 3-bisphosphoglycerate as a result of phosphate loading.
A recent study investigated the effects of phosphate supplementation over a 7-day period (1). Following phosphate supplementation there was a 25% increase in red blood cell 2, 3-bisphosphoglycerate. Exercise performance was not measured in this study but it was hypothesised that a 25% increase in 2 3-bisphosphoglycerate would influence VO2 max and could result in performance benefits to high intensity endurance athletes through improved oxygen offloading at the tissues, allowing the athlete to exercise at a greater work rate for longer.
Overall, some studies show a performance benefit with phosphate supplementation (2-4), whilst others do not (5-7).
Several confounding influences may explain these mixed results, including, mode of exercise, exercise intensity, dietary intake, type of supplement, supplemental dose, length of loading, fitness level of subjects and analysis technique. These differences in study design make it difficult to draw definitive conclusions.
On the whole the research suggests that in excess of 2-3 days of phosphate ingestion is required is required to see changes in 2 3-bisphosphoglycerate. This suggests that acute phosphate supplementation is unlikely to be effective and longer term regimes may be required. Generally an increase in 2 3-bisphosphoglycerate results in functionally improved performance and may benefit high intensity endurance exercise. Future well-designed studies of adequate duration should investigate phosphate loading further.
Rating of Efficacy for Sodium Phosphate
- Bremner K., Bubb W.A., Kemp G.J., Trenell M.I. and Thompson C.H. The effect of phosphate loading on erythrocyte 2,3-bisphosphate levels. Clinica Chimica Acta. 323:111-114, 2002.
- Cade R., Conte M., Zauner C., Mars D., Perterson J., Lunne D., Hommen N. and Packer D. Effects of phosphate loading on 2,3-diphosphoglycerate and maximal oxygen uptake. Med Sci Sports Exerc. 16:263-268, 1984.
- Kreider R.B., Miller G.W., Williams M.H., Somma C.T. and Nasser T.A. Effects of phosphate loading on pxygen uptake, ventilatory anaerobic threshold, and run performance. Med Sci Sports Exerc. 22:250-256, 1990.
- Kreider R.B., Miller G.W., Schenck D., Cortes C.W., Miriel V., Somma C.T., Rowland P., Turner C. and Hill D. Effects of phosphate loading on metabolic and myocardial responses to maximal and endurance exercise. Int J Sport Nutr. 2:20-47, 1992.
- Duffy D.J. and Conlee R.K. Effects of phosphate loading on leg power and high intensity treadmill exercise. Med Sci Sports Exerc. 18:674-677, 1986.
- Galloway S.D., Tremblay M.S., Sexsmith J.R. and Roberts C.J. The effects of acute phosphate supplementation in subjects of different aerobic fintess levels. Eur J Appl Physiol. 72:224-230, 1996.
- Goss F., Robertson R.J., RIechman S., Zoeller R., Dabayebeh I.D. and Moyna N. Effect of potassium phosphate supplementation on perceptual and physiological responses to maximal graded exercise. Int J Sport Nutr Exerc Metab. 11:53-62, 2001.