Hydrate in Moderation to avoid Over-Hydration or “Water Intoxication”
For years, heath care and fitness professionals have stressed the importance of fluid intake and replacement in preventing dehydration. Therefore, most health conscience individuals are educated about dehydration and cases of dehydration have decreased in recent years.
Yet, in some cases, people may take dehydration prevention a bit too far and unintentionally drink too much water. Drinking an excessive surplus of water can lead to over-hydration or hyponatremia. Although hyponatremia is rare and seen primarily in serious endurance athletes, such as marathon runners, it can be dangerous and fitness enthusiasts should be aware of the condition.
In a study published in The New England Journal of Medicine (April 2005) of 488 runners that provided a usable blood sample at the finish line of the 2002 Boston Marathon, 13% had hyponatremia; 0.6 percent had critical hyponatremia.
The MedTerms.com medical dictionary defines hyponatremia as an abnormally low concentration of sodium in the blood. Hyponatremia is also known as “water intoxication”. Sodium (salt and chloride) is an electrolyte, which helps the body distribute water. This is essential for water balance and for your muscles and organs to function effectively. Electrolytes are lost through sweat. When exercising, our body temperature rises and we sweat to keep cool. The more we sweat, the more sodium lost. Sweat loss varies from as little as 16 ounces to over three quarts during each hour of exercise (Gatorade Sports and Science Institute). For this reason, it is important to replace lost body fluids during and after exercise. To completely replace these fluids, you must not only replace water, but also sodium and chloride. Those who consume excessive amounts of water after exercise can further deplete sodium and chloride levels, leading to electrolyte depletion and possibly over-hydration.
What Are the Symptoms?
Over-hydration is disruptive to nerve cell function and can produce symptoms of lightheadedness or mild vertigo. Because brain cells are susceptible to fluid imbalances, over-hydration and water intoxication can produce neurological symptoms such as altered personality, and disoriented behavior. Water intoxication can also result in convulsions, circulatory shock, coma, and death.
Immediate medical attention is required when symptoms of over-hydration or water intoxication occur. To avoid complications, fluid intake (which is usually restricted and very slowly re-administered over many hours) should be very carefully monitored by a healthcare professional.
Can I Avoid Over-Hydration?
Yes. Over-Hydration and water intoxication can be avoided with careful monitoring of fluid intake when perspiring heavily, or when ill with diarrhea or vomiting.
Under these conditions, drinking plain water will not restore sodium loss nor will it adequately re-hydrate the body. Because they contain sodium, many Naturally Bottled Waters can help to quickly restore sodium loss.
Consultation with a health care professional can help athletes in heavy training, and individuals who are ill, to obtain adequate fluid intake and to avoid the risk of over-hydration.
Hyponatremia among Runners in the Boston Marathon
New England Journal of Medizine, April 2005