An acute oral dose of caffeine does not alter glucose kinetics during prolonged dynamic exercise in trained endurance athletes

Abstract.This study investigated the possible influence of oral caffeine administration on endogenous glucose production and energy substrate metabolism during prolonged endurance exercise. Twelve trained endurance athletes [seven male, five female; peak oxygen consumption ($$\dot V{\rm O}_{{\rm 2peak}} $$ ) = 65.5 ml·kg–1·min–1] performed 60 min of cycle ergometry at 65% $$\dot V{\rm O}_{{\rm 2peak}} $$