Phosphate loading and the effects on v02max in trained cyclists

Abstract

It is known that an increased level of red blood cell 23-diphos- phoglycerate (DPG) shifts the oxyhemoglobin dissociation curve to the right, thus allowing a greater unloading of oxygen at the tissue level. It has been hypothesized that phosphate might help increase VOjnax by increasing 2$ -DPG level. Eight trained cyclists underwent three cycle ergometer tests (control, placebo, and experimental) to determine whether phosphate ingestion had any positive effect on VOjnax, time to exhaustion, serum 23- DPG, and serum phosphate levels. We found no change between the control, placebo, or experimental conditions in pretest serum phosphate levels, but we did find increases in 23-DPG levels in the phosphate condition (p