Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects

• Published in: Journal of human hypertension Vol. 21; no. 7; pp. 564 - 570
• Main Authors: CALLEGARO, C. C, MORAES, R. S, NEGRAO, C. E, TROMBETTA, I. C, RONDON, M. U, TEIXEIRA, M. S, SILVA, S. C, FERLIN, E. L, KRIEGER, E. M, RIBEIRO, J. P
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 01-07-2007; Nature Publishing Group
• Subjects: Acute effects; Adult; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood flow; Blood Flow Velocity - physiology; Blood pressure; Blood Pressure - physiology; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Control; Drinking - physiology; Experimental diseases; Female; Forearm; Heart rate; Heart Rate - physiology; Hemodynamics; Humans; Hypertension; Hypertension - physiopathology; Male; Medical sciences; Middle Aged; Physiological aspects; Risk factors; Sympathetic nerves; Sympathetic Nervous System - physiology; Vagus nerve; Vascular Resistance - physiology; Brazil; Human; Hypertension; Sympathetic nerve; baroreflex sensitivity; Variability; Cardiovascular disease; Ingestion; Heart rate; blood pressure variability; Autonomic nervous system; heart rate variability; Baroreflex; muscle sympathetic nerve activity; Arterial pressure; Blood pressure
• ISSN: 0950-9240; 1476-5527
• DOI: 10.1038/sj.jhh.1002188

In patients with severe autonomic dysfunction, water ingestion elicits an acute pressor response. Hypertension may be associated with changes in cardiovascular autonomic modulation, but there is no information on the acute effects of water ingestion in patients with hypertension. In this study, we compared the effect of acute water ingestion on haemodynamic and autonomic responses of hypertensive and normotensive individuals. Eight patients with mild hypertension were compared to 10 normotensive individuals. After 30 min resting in the supine position all subjects ingested 500 ml of water. At baseline and after water ingestion, venous blood samples for plasma volume determination were collected, and electrocardiographic tracings, finger blood pressure, forearm blood flow and muscle sympathetic nerve activity (MSNA) were obtained. Water ingestion resulted in similar and minor reduction in plasma volume. Systolic and diastolic blood pressure increased in both hypertensive (mean+/-s.d.: 19/14+/-6/3 mm Hg) and normotensive subjects (17/14+/-6/3 mm Hg). There was an increase in forearm vascular resistance and in MSNA. Heart rate was reduced (hypertensive: 5+/-1 beats/min, normotensive: 5+/-6 beats/min) and the high-frequency component of heart rate and systolic blood pressure variability was increased. In hypertensive and normotensive individuals, acute water ingestion elicits a pressor response, an effect that is most likely determined by an increased vasoconstrictor sympathetic activity, and is counterbalanced by an increase in blood pressure and heart rate vagal modulation.