In response to two deaths in the United States from over-hydration last summer, new guidelines were developed for water consumption during athletic activities. WMRA’s Kara Lofton talked to the UVa physician who chaired the team of 16 international experts who produced the final recommendation.
In the the United States accidental death from over-hydration, called exercise-associated hyponatremia, is just as common as death from dehydration. UVa physician Dr. Mitchell Rosner said the problem is that athletes are often encouraged to drink as much as they can during athletic activities, regardless of how thirsty they are. Drinking more water than the body needs can cause an imbalance in the internal salt to water ratio.
MITCHELL ROSNER: When you have an excess of water over salt, that leads to cells in our body swelling. Especially worrisome is the cells in the central nervous system, in the brain. When that happens it can cause confusion, seizures and in the extreme, death.
These events are still rare – current literature cites symptomatic hyponatremia as occurring in less than 1% of the athletic population, and then occurring most often for athletes participating in endurance events.
Rosner says in most cases, what he and the other experts found is that preventing hyponatremia is as simple as listening to your own thirst mechanism.
ROSNER: Thirst is an evolutionarily conserved mechanism that works. It’ll signal when your body is low on water and you need to drink, and when your thirst goes away that’s a sign that you don’t need to drink anymore. So that’s the safest, easiest way to do this…You can’t give anybody a blanket statement like drink a liter per hour or drink eight cups per hour because everybody is a little bit different in terms of how much sweat they lose, what the activity may be… it just doesn’t work.