Exercise and Hyponatremia

Drinking Water
Too much liquid can lead to hyponatremia.
Too much liquid can lead to hyponatremia.

Exercise and Hyponatremia

Over-hydrating (drinking too much) can lead to a condition called hyponatremia. This is serious and sometimes deadly. Hyponatremia is a metabolic condition in which there is not enough sodium in the body fluids outside the cells. Exercise-related hyponatremia is thought to be caused by ingesting too much liquid, both before and during exercise.

Sodium is found mostly in the body fluids outside the cells. It is very important for maintaining blood pressure. Sodium is also needed for nerves and muscles to work properly.

When the amount of sodium in fluids outside cells drop, water moves into the cells to balance the levels. The result is the cells then swell with too much water. Although most cells can handle this swelling, brain cells cannot. Brain swelling causes most of the symptoms of hyponatremia. Hyponatremia is the most common electrolyte disorder in the United States. Anyone who drinks too much without adequately replacing the sodium that is naturally lost in sweat risks hyponatremia. Certain athletes and fitness buffs should be especially careful to avoid hyponatremia, including:

  • Those who exercise for more than 4 hours.
  • Exercisers who also practice a low-salt diet.
  • Marathoners and triathletes just beginning to train and tend to be over zealous about hydration.
  • The “salty sweater” – someone who’s skin and clothing becomes caked with a white residue after exercising.
Bottled water
Bottled water

In simple terms, hyponatremia is usually caused when a person drinks too much water, which results in electrolytes being flushed from your blood. A safe and healthy way to reduce the risk of developing hyponatremia is to consume a sports drink instead of water. Other causes of hyponatremia include:

  • Burns.
  • Congestive heart failure.
  • Diarrhea.
  • Diuretic medications, which increase urine output.
  • Kidney diseases.
  • Liver cirrhosis.
  • Syndrome of inappropriate anti-diuretic hormone secretion (SIADH).
  • Sweating.

Symptoms of Hyponatremia

  • Rapid weight gain.
  • Swollen hands and feet.
  • Throbbing headache.
  • Confusion.
  • Dizziness.
  • Nausea.
  • Severe fatigue.
  • Lack of coordination.
  • Wheezy breathing.
  • Cramping.
  • Bloated stomach.
  • Seizure.

Hyponatremia can result in seizure, coma, and even death. Seek emergency treatment if you think you are showing symptoms of hyponatremia. In most cases, treatment includes an intravenous solution of a concentrated sodium solution, a diuretic medication to speed water loss and an anti-convulsive medication in case of seizure.

This is great information to know, especially if you drink a heap of liquids. See Why Water?

Author: Jeni

Certified by the Professional School of Fitness and Nutrition in March, 1995; honored for exemplary grades. Practicing fitness and nutrition for over 20 years. Featured in the Feb. 1994 issue of "Shape" magazine. Featured in Collage in the spring issue of 1995 Low fat recipe's published in Taste of Home, Quick Cooking, and the Milwaukee Journal-Sentinel, among others. September, 2001: Featured in "Winning The War on Cholesterol" By Rodale Publishing

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