SPRIET, L.L., and G.J.F. HEIGENHAUSER. Regulation of pyruvate dehydrogenase (PDH) activity in human skeletal muscle during exercise. Exerc. Sport Sci. Rev., Vol. 30, No. 2, pp. 91–95, 2002. Pyruvate dehydrogenase is a mitochondrial multienzyme complex that catalyzes the conversion of pyruvate to acetyl-coenzyme A and regulates the entry of carbohydrate into the tricarboxylic acid cycle for oxidation. During exercise, pyruvate dehydrogenase activation in human skeletal muscle is proportional to the relative aerobic power output (percent o2max) and is regulated by increases in Ca2+, free ADP, and pyruvate concentrations.