Hyponatremia
Hyponatremia is a useful word I learned from GN of Uni ‘76. Wendy Bumgardner says
A study of Boston Marathon runners found that 13% had drunk too much water and developed hyponatremia - a dangerous and deadly dilution of their blood. The study was published in the April 14, 2005 issue of the New England Journal of Medicine.
The study looked at several factors, and found that those who were slowest (having more time to drink on the course), who were very low body mass, and who gained weight during the event were the ones most likely to develop hyponatremia.
The study found that it didn’t matter whether the racer drank both water and sports drink, or whether they took nonsteroidal antiinflammatory drugs (such as ibuprofen or naprosyn) or were female.
These conclusions are a concern for long distance walkers. The old advice was “drink, drink, drink,” and to drink sports drink that had salt replacement in order to prevent hyponatremia. However, this study suggests that even if drinking sports drink there is a risk of hyponatremia from too much fluids. Walkers should continue to use sports drink or salty snacks rather than only drinking water, but it may not be the only solution to prevent hyponatremia.