Phosphate loading

Since the early 1990s, scientists have been interested in the possibility of increasing the dietary consumption of phosphorus to improve cardiovascular and metabolic function during exercise. Several of the early studies suggested that phosphate loading, which involves ingestion of sodium phosphate as a dietary supplement, is an effective ergogenic aid.

Proposed ergogenic benefits

Phosphate loading has been proposed to have numerous potential benefits during exercise. These include elevation of extracellular and intracellular phosphate levels, which would increase the availability of phosphate for oxidative phosphorylation and phosphocreatine synthesis, thus improving the body’s energy production capacity. Phosphate loading is also thought to enhance 2,3-diphosphoglycerate(2,3-DPG) synthesis in the red blood cells.

This increase in 2,3-DPG would shift the oxygen-hemoglobin dissociation curve to the right, permitting greater oxygen unloading in the active muscles. Thus, phosphate loading has been proposed to improve the cardiovascular response to exercise, improve the body’s buffering capacity, and consequently improve endurance capacity and performance.

Proven effects

Only a few studies have been conducted to determine the ergogenic benefits of phosphate loading. Unfortunately, the results are divided. Several studies showed significant improvements in VO₂max and time to exhaustion. However, several other showed no effects. There appear to be some potential benefits to phosphate loading, but additional research is needed to confirm this.

Risks of phosphate loading

At this time, no known risks are associated with phosphate loading. However, because insufficient research has been conducted to date, more studies are needed to determine its safety.