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Definition: Hyponatremia

Hyponatremia is a condition that occurs from drinking too much water.

Also known as water intoxication, hyponatremia occurs when the sodium in your blood is diluted by excess water. The body's balance of electrolytes is pushed outside of safe limits, disrupting normal brain function. If water enters the body more quickly than it can be removed after intense sweating and sodium loss, body fluids are diluted and this can be a problem for marathoners. Because endurance runners lose sodium through sweat, drinking too much water during endurance activities, such as marathons and triathlons, can dilute the sodium content of your blood.

Some things to note:

  • Hyponatremia also occurs more often in women than in men.
  • Not being acclimated to hot weather can increase the amount of sodium you lose through sweating during exercise.
  • The symptoms of hyponatremia can mimic the symptoms of dehydration. Pay attention to a headache that won’t go away, vomiting and confusion. Seek help from a doctor.
  • To confirm low blood sodium, laboratory tests — including blood tests and possibly urine tests — are necessary.

Be safe when you run in the heat!!! Experiment with all those different sports drinks out there to find one that suits your needs.

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