Water drinking as a treatment for orthostatic syndromes

Purpose: Water drinking increases blood pressure in a substantial proportion of patients who have severe orthostatic hypotension due to autonomic failure. We tested the hypothesis that water drinking can be used as a practical treatment for patients with orthostatic and postprandial hypotension, as well as those with orthostatic tachycardia. Subjects and methods: We studied the effect of drinking water on seated and standing blood pressure and heart rate in 11 patients who had severe orthostatic hypotension due to autonomic failure and in 9 patients who had orthostatic tachycardia due to idiopathic orthostatic intolerance. We also tested the effect of water drinking on postprandial hypotension in 7 patients who had autonomic failure. Patients drank 480 mL of tap water at room temperature in less than 5 minutes. Results: In patients with autonomic failure, mean (± SD) blood pressure after 1 minute of standing was 83 ± 6/53 ± 3.4 mm Hg at baseline, which increased to 114 ± 30/66 ± 18 mm Hg (P <0.01) 35 minutes after drinking. After a meal, blood pressure decreased by 43 ± 36/20 ± 13 mm Hg without water drinking, compared with 22 ± 10/12 ± 5 mm Hg with drinking (P <0.001). In patients with idiopathic orthostatic intolerance, water drinking attenuated orthostatic tachycardia (123 ± 23 beats per minute) at baseline to 108 ± 21 beats per minute after water drinking ( P