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.
Resources:
Hyponatremia among Runners in the
Boston
Marathon
New
England Journal of Medizine, April
2005
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The Water Connoisseur
