Water intoxication: a possible complication during endurance exercise

Med Sci Sports Exerc. 1985 Jun;17(3):370-5.


Four athletes developed water intoxication (hyponatremia) during endurance events lasting more than 7 h. The etiology of the condition appears to be voluntary hyperhydration with hypotonic solutions combined with moderate sweat sodium chloride losses. The reason why the fluid excess in these runners was not corrected by increased urinary losses is unknown. When advised to drink less during prolonged exercise, three of the athletes have subsequently completed prolonged endurance events uneventfully.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Drinking
  • Female
  • Humans
  • Hypotonic Solutions
  • Male
  • Middle Aged
  • Physical Endurance*
  • Running*
  • Sweating
  • Water Intoxication / etiology*


  • Hypotonic Solutions