Hydration Can Reduce Fainting

Two studies presented at the recent meeting of the American Heart Association show that drinking at least two glasses of water can prevent fainting when standing after giving blood.

Each year, more than 150,000 donors faint after giving blood and rising quickly from sitting in a chair. When you rise quickly, from sitting or lying to standing, or when you stand for a long time, you may feel faint because gravity pulls blood down from your brain and you have to wait for the next heart beat to pump blood back up. This is called orthostatic hypotension. Two studies, one from Vanderbilt University in the United States, the other from Humboldt University, in Germany, show that drinking at least 16 ounces of water helps prevent fainting after donating blood. The same principle applies when you do not drink enough fluid during exercise. If you often feel dizzy or faint after you exercise or when you change position, try drinking more water.

David Robertson, MD, of Vanderbuilt, Dr. Schroeder of Humbolt University in Berlin at the American Heart Association's 56th Annual Fall Conference and Scientific Sessions of the Council for High Blood Pressure Research.

Checked 8/31/08

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