Cerebral lactate uptake during exercise is driven by the increased arterial lactate concentration

Abstract

During exercise the brain consumes lactate as a substitute for glucose. Propranolol has previously attenuated this cerebral lactate uptake, suggesting a β-adrenergic transport mechanism. However, in the present study, we demonstrate that the fractional extraction of arterial lactate by the brain is unaffected by propranolol throughout the incremental exercise to exhaustion. We conclude that cerebral lactate uptake during exercise is passively driven by the increasing arterial concentration, rather than by a β-adrenergic mechanism within the brain.