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At least 14 people have died from drinking too much water while doing sport, according to new research.

Victims of water intoxication include marathon runners and football players – but deaths have occurred even during yoga and lawn green bowling.

Those who are playing sports or exercising should drink only when thirsty and not “preload”, say experts.

Flooding the body with liquid, even sports drinks, can cause a life-threatening condition EAH (exercise associated hyponatremia).

And excessive fluid intake does not stop fatigue, muscle cramps or heat stroke.

(Image: Getty)

Dr James Winger, of Loyola University, Illinois, said: “Muscle cramps and heatstroke are not related to dehydration.

"You get heat stroke because you are producing too much heat.”

Mild symptoms include lightheadedness, dizziness, nausea, puffiness and gaining weight during an athletic event.

More severe cases lead to vomiting, headache, altered mental status such as confusion, agitation and delirium, as well as seizure and coma.

It has occurred during endurance competitions such as marathons, triathlons, canoe races and swimming; military exercises; hiking; football; vigorous exercise during college initiation rituals; and even yoga and lawn bowling.

Athletes often are mistakenly advised to "push fluids" or drink more than their thirst dictates by, for example, drinking until their urine is clear or drinking to a prescribed schedule.

But excessive fluid intake does not prevent fatigue, muscle cramps or heat stroke.



There is no universal rule about how much water is too much, but the Mayo Clinic in New York suggests drinking at least eight 8-ounce glasses of fluid a day - equivalent three and a third British pints.

But exercise calls for an extra 1.5 to 2.5 cups while during warmer temperatures and pregnancy people should drink more.