The effects of normoxic endurance exercise on erythropoietin (EPO) production and the impact of selective β1 and non-selective β1\u2009+\u2009β2 adrenergic receptor blockade.

Abstract

PURPOSE\nHabitual endurance exercise results in increased erythropoiesis, which is primarily controlled by erythropoietin (EPO), yet studies demonstrating upregulation of EPO via a single bout of endurance exercise have been equivocal. This study compares the acute EPO response to 30\xa0min of high versus 90\xa0min of moderate-intensity endurance exercise and whether that response can be upregulated via selective adrenergic receptor blockade.\n\n\nMETHODS\nUsing a counterbalanced, cross-over design, fifteen participants (age 28\u2009±\u20098) completed two bouts of running (30-min, high intensity vs 90-min, moderate intensity) matched for overall training stress. A separate cohort of fourteen participants (age 31\u2009±\u20096) completed three bouts of 30-min high-intensity cycling after ingesting the preferential β1-adrenergic receptor (AR) antagonist bisoprolol, the non-preferential β1 +\u2009β2 antagonist nadolol or placebo. Venous blood was collected before, during, and after exercise, and serum EPO levels were determined by ELISA.\n\n\nRESULTS\nNo detectable EPO response was observed during or after high intensity running, however, in the moderate-intensity trial EPO was significantly elevated at both during-exercise timepoints (+\u20096.8%\u2009±\u20092.3% at 15\xa0min and +\u20098.7%\u2009±\u20092.2% at 60\xa0min). No significant change in EPO was observed post-cycling or between the trials involving βAR blockade.\n\n\nCONCLUSION\nNeither training mode (running or cycling), nor beta-blockade significantly influenced the EPO response to 30\xa0min of high-intensity exercise, however, 90\xa0min of moderate-intensity running elevated EPO during exercise, returning to baseline immediately post-exercise. Identifying the optimal mode, duration and intensity required to evoke an EPO response to exercise may help tailor exercise prescriptions designed to maximize EPO response for both performance and clinical applications.