Times of India
08 July 2010
Washington, UK

The health benefits of water are manifold. Now, add two more to the list – it raises alertness and keeps blood pressure within normal range, according to a new study.

Researchers at Vanderbilt University Medical Center have carried out the study and found drinking water increases the activity of the nervous system, which raises alertness, blood pressure and energy expenditure.

They first observed water’s curious ability to increase blood pressure about 10 years ago, in patients who had lost their baroreflexes – the system that keeps blood pressure within a normal range.

“The observation came as a complete surprise. We had to unlearn the idea that water had no effect on blood pressure, which is what all medical students had been told until the last couple of years,” lead researcher David Robertson said.

Although water does not significantly raise blood pressure in healthy young subjects with intact baroreflexes, the experts found that it does increase sympathetic nervous system activity and constrict blood vessels (which prevents pooling of blood in the extremities).

In their latest study, the researchers found water introduced directly into the stomach or duodenum (the first part of the small intestine) raised blood pressure, which ruled out an oral or oesophageal mechanism for the response.

The researchers determined that water dilutes the plasma in the blood vessels leading away from the duodenum and that this short–lived reduction in salt concentration is responsible for water’s blood pressure–raising effect. PTI