Water intoxication: Drink only when thirsty during exercise

A new study has suggested that hikers, football players, endurance athletes and elite and recreational exercisers can avoid water intoxication by drinking only when thirsty during exercise.

As per the updated consensus statement on exercise-associated hyponatremia (EAH), using the innate thirst mechanism to guide fluid consumption is a strategy that should limit drinking in excess and developing hyponatremia (low blood sodium) while providing sufficient fluid to prevent excessive dehydration.

Lead author Tamara Hew-Butler of Oakland University said that the major goal was to re-educate the public on the hazards of drinking beyond thirst during exercise.

The updated statement emphasizes a more balanced approach to hydration, especially during the summer months, when exercising in the heat increases the risk for developing dangerously low blood sodium levels associated with overdrinking.

Hew-Butler added that the release of these recommendations is particularly timely, just before sports training camps and marathon training begins within the United States, where the majority of EAH deaths have occurred.

Exercise-associated hyponatremia, sometimes called 'water intoxication,' refers to reductions in the body's sodium level occurring during or up to 24 hours after physical activity. Especially before the drop in sodium level becomes too severe, EAH may have no or only mild symptoms.

When symptoms occur, they typically include headache, vomiting, and confusion or seizures, resulting from swelling of the brain (cerebral edema). Without immediate treatment, severe EAH can be rapidly fatal.

The study appears in Clinical Journal of Sport Medicine.