Death from overhydration is rare but also preventable. You simply need to drink less. However, that is sometimes easier said than done with all the conflicting and often incorrect advice that exists about how much water you should consume after intense activity. Family practice physician James Winger of Loyola University Health System in Illinois studied fluid-intake awareness using marathon runners. Per a 2011 Washington Post article:

Winger’s study, published [in 2010] by the British Journal of Sports Medicine, measured mistaken beliefs about hydration among runners by surveying 197 Chicago-area racers in 2009. Most — 58 percent — knew to drink only when thirsty. … The rest of the runners in Winger’s survey were likely to follow the older guidelines, which called for drinking set amounts before, during and after a race or drinking all they could hold. The thinking behind that was that even slight dehydration would hurt performance and that by the time a runner felt thirsty, the negative effects of dehydration had already begun. … Another belief that Winter found among runners was that electrolyte-laden beverages, such as sports drinks, can prevent the condition by replacing sodium lost via sweating. In fact, Winger says in his study, overconsumption of sports drinks can lead to hyponatremia just as easily as drinking too much water can. … Based on his research, Winger says runners can avoid hyponatremia by paying little attention to advertisements for sports drinks, outdated if well-meaning hydration advice and their own beliefs. “I like the simplicity of the message ‘Drink when you’re thirsty,’ ” he says. “It’s not something you have to tell your body to do.”