What is your approach to preventing exercise-associated hyponatremia?

Exercise-associated hyponatremia is typically due to fluid intake in excess of fluid loss. Therefore, athletes should avoid overconsumption of fluids. Rather, athletes should drink according to thirst. In addition, it is important to recognize that electrolyte-containing sport drinks does not provide much protection since these beverages are markedly hypotonic to the plasma sodium concentration.

I just gave a lecture on this at Kidney Week, Once it is on-line I can put a link here.

Drink to thirst.

If first marathon and you have access to scales during the event, weigh yourself at intervals.