A Novel Perspective on Water Intake's Benefits on Cardiovascular Function: A Simple Strategy for Heart Health

Background Hydration has been increasingly recognized as a modifiable factor with potential cardiovascular relevance. Whether acute water intake improves hemodynamic, vascular, and autonomic outcomes—and whether these responses differ according to home blood pressure phenotype—remains insufficiently characterized. Aim To evaluate the effects of acute water intake on cardiovascular and autonomic parameters in men, and to explore associated changes in circulating renin–angiotensin system peptides. Methods Thirty-seven healthy men underwent two laboratory assessments under standardized conditions: after fasting (post-fasting) and after acute water intake (post-water). Participants were categorized by home-based blood pressure as normal (N-BP; <130/≤80 mmHg) or abnormal (Ab-BP; ≥130 and/or > 80 mmHg). Hemodynamic and vascular parameters—including peripheral and central blood pressure indices, augmentation index, and pulse wave velocity—were assessed, alongside electrocardiography-derived heart rate variability spectral analysis. In a subset (N = 11), plasma RAS peptides were quantified by liquid chromatography–tandem mass spectrometry. Results Post-water intake, participants showed significant drops in renin-angiotensin peptides, heart rate, and augmentation index, with notable rises in very low frequency and heart rate variability, indicating robust autonomic modulation and potential cardiovascular benefits. Conclusions Acute water intake modulates hemodynamic, vascular, and autonomic parameters in men, with phenotype-dependent responses based on home blood pressure. Thus, hydration is a simple, impactful strategy to enhance cardiovascular health and guide personalized care.