Water
Blood Pressure Drug:
Water:
The Unexpected Blood Pressure Drug
Patients
who suffer from autonomic nervous system failure can turn to a new
treatment for their blood pressure abnormalities: a large glass
of water. Investigators at Vanderbilt's Autonomic Dysfunction Center
report in the February 8th issue of the journal Circulation that
water has a powerful blood pressure raising effect in these patients.
Water
also raises blood pressure in older normal subjects, but not in
young normal subjects. The studies suggest that water is an important
unrecognized factor in clinical studies of blood pressure medications.
"Water
is not just a neutral substance, and it cannot be considered a 'placebo'
with regards to blood pressure," said Dr. John R. Shannon,
instructor of Medicine and Pharmacology. "As physicians, we
may ask our hypertensive patients if they just drank a cup of coffee
or smoked a cigarette when we measure their blood pressure, but
we would never think to ask if they had anything to drink in the
last hour. Perhaps we should. It might make the difference in whether
or not we adjust their medications."
On
the average, 16 ounces of tap water raised blood pressure about
40 millimeters of mercury in patients with autonomic failure. Blood
pressure started increasing within two or three minutes after the
water was ingested, increased rapidly over the next 15 minutes,
and then began to decrease after about 60 minutes. Drinking more
water at 60 minutes caused the blood pressure effect to be sustained
for another hour.
In
older normal subjects, the average increase in blood pressure was
11 millimeters of mercury.
There
is something about the water itself that causes the increase in
blood pressure; intravenous infusion of 16 ounces of sugar solution
did not elicit the effect. In addition, the effect is "dose-dependent"
-- the higher the water intake, the larger the increase in blood
pressure.
"We
do not know how water raises blood pressure, but it is the solute-free
water itself, whether warm, room temperature, or cold that elicits
the effect," said Dr. Jens Jordan, a former postdoctoral fellow
in Clinical Pharmacology and lead author of the study.
"Water
might be increasing blood pressure by interacting with osmoreceptors
(which sense salt concentrations) or stretch receptors in the stomach
or liver," added Jordan, who is currently director of the Clinical
Research Center at the Franz Volhard Klinik of Humboldt University
in Berlin, Germany.
The
studies suggest a new and more effective treatment for the blood
pressure abnormalities suffered by patients with autonomic failure.
By raising blood pressure, water ingestion during the day can enhance
a patient's functional abilities. At Vanderbilt, the careful administration
and withholding of water at various times during the day has proven
successful as the only form of blood pressure treatment for some
patients with autonomic failure.
Although
further work is required to understand why water raises blood pressure
in older normal subjects, the studies suggest that physicians need
to be aware of water as a variable to consider in assessing blood
pressure levels. In addition, water intake is a variable that needs
to be controlled in short-term pharmacological studies of drugs
that increase and decrease blood pressure.
Editor's
Note: Click here
because you'll want to read our detailed review of a water purifying
unit that produces crystal clear healthy water for less than 10
cents a gallon.
Disclaimer:
Throughout this website, statements are made pertaining to the properties
and/or functions of food and/or nutritional products. These statements
have not been evaluated by the Food and Drug Administration and
these materials and products are not intended to diagnose, treat,
cure or prevent any disease.