Renin–angiotensin system inhibition, erythropoiesis, and aerobic training responsiveness

This is the authors' abstract. We don't add key points for this paper.

Dear Editor, Guo et al. (2025) report that angiotensin II type-1 receptor blockade (valsartan) combined with 8 weeks of endurance training reduced haemoglobin mass (Hbmass) in women and was associated with no statistically significant increase in VO2peak, in contrast to men.1 These findings may be interpreted as indicating that pharmacological inhibition of the renin–angiotensin system (RAS) abolishes endurance-training responsiveness in women. We believe such an interpretation warrants caution. In a randomized, double-blind, placebo-controlled trial including equal numbers of women and men (n = 24 per sex), we examined the effects of angiotensin-converting enzyme inhibition (ACEi; enalapril 20 mg/day) during 8 weeks of supervised exercise training.2 As expected, ACEi lowered blood pressure independently of sex and exercise training. Importantly, training-induced improvements in VO2peak (∼13%) and skeletal-muscle endurance were preserved in both women and men, irrespective of ACEi treatment. Consistent with this, functional performance outcomes—including rowing performance and cycling peak power—improved to a similar extent across treatment and sex. Although ACEi reduced Hbmass by ∼3%, this haematological effect was not associated with attenuated aerobic or functional adaptations to exercise training.2