Abstract
Beneficial adaptations to exercise depend on the normal function of the endocrine system. Whether commonly prescribed antihypertensive medication inhibits erythropoietin (EPO) production with exercise, a key response to enhance aerobic capacity, remains unknown. Healthy adults (n = 63, 42.3 ± 16.5 yr, 52% ♀) matched by age, sex, and physical activity were randomized in a blinded and crossover manner to orally ingest valsartan (angiotensin II type 1 receptor-blockade, AT1-blockade) or placebo (calcium carbonate, PBO) 4 h before starting the experimental protocol. Before and after 1 h of moderate cycling exercise, blood samples were taken to measure circulating EPO and EPO-regulating hormones along with blood pressure. Cardiac structure/function and peak pulmonary O2 consumption (VO2peak) were assessed during exercise. AT1-blockade decreased heart volumes (left atrium and ventricle) during exercise compared with PBO, particularly in men (P ≤ 0.036). Whole-body O2 extraction and VO2peak were unaffected by AT1-blockade irrespective of sex (P ≥ 0.325). Before and after exercise, AT1-blockade reduced arterial blood pressures (systolic, diastolic) in both sexes (P < 0.001). A condition × time interaction was detected for circulating EPO (P = 0.002), such that AT1-blockade decreased EPO at 3-h post-exercise compared with PBO (P ≤ 0.025). The effect of exercise on EPO-regulating hormones (angiotensin II, aldosterone, copeptin) was diminished with AT1-blockade. Sex per se did not influence the endocrine response to AT1-blockade. In conclusion, in a randomized, double-blind and placebo-controlled study design, AT1-blockade abolishes the acute EPO response to exercise in women and men. Antihypertensive medications hindering AT1 signaling may restrict key endocrine responses to exercise.