GLUCOSE KINETICS DURING EXERCISE IN TRAINED MEN

Abstract

Six trained men were studied to examine the relative increases in hepatic glucose output and peripheral glucose uptake during 40 min of exercise at 75% VO2max. Rates of appearance (Ra) and disappearance (Rd) were measured using a primed, continuous intravenous infusion of D-[3-3H]glucose. Plasma glucose increased (P < 0.05) from 4.8 +/- 0.2 mmol l-1 at rest to 6.2 +/- 0.5 mmol l-1 after 40 min of exercise. Both Ra and Rd increased (P < 0.05) during exercise, however, during the early phase of exercise, Ra exceeded Rd (P < 0.05). Ra peaked at 42.0 +/- 3.2 mumol kg-1 min-1 after approximately 15 min of exercise. In contrast, the highest Rd of 33.9 +/- 4.3 mumol kg-1 min-1 was measured at the e..