What causes Hyponatremia in runners?
For the most part, studies indicate water overload as and sodium concentration scenario as the principal cause of hyponatremia. The woman who died in the Chicago Marathon is reported to have drunk, “gallons and gallons of water daily,” in the two weeks prior to the Windy City race. In his Ironman studies, Dale Speedy has come across hyponatremia cases where athletes have drunk as much as 23 litres of fluid during the race. However, despite the strong correlations between water overload, Speedy admits that there is a lot still unknown about what are the causes behind it all. Right now, for example, expert opinion is divided as to the relationship between over hydration and the loss of sodium via sweat. In an address to a sports nutrition conference in February 2001, Dr E. Randy Eichner, M.D., promoted the role of salt loss to sweat as a contributing cause to hyponatremia.
