I’ve heard lately from several sources (first concerning ecstasy users at raves, more recently in regards to a Boston Marathon casualty) that drinking too much water can cause death.
So- how much is too much? I’m assuming it’s about drinking too much in a certain window of time. I drink about 1.5 gallons a day, but it’s over the course of 10 hours or so.
If you drink too much in any situation, you can die of hyponatremia, which is the condition of not having enough salt in the bloodstream. The sodium/water balance is one of the more important equilibriums we must reach for physical health, and disrupting it severely can be lethal.
So, don’t drink faster than you can pee, and don’t eat more than you can balance out with water.
I just wanted to chime in and say, I asked this same question about 6 months ago and got nearly no concrete answers from the Dopers. Here’s hoping you have better luck, because I too would like an answer.
Well, the military set it’s guidlines at 1 to 1.5 quarts per hour and not more than 12 quarts (three gallons) in a day. (cite). 1.5 gallons over 10 hours is 0.6 quarts per hour so it’s probably OK. Particularly if you haven’t noticed any side-effects.
The biggest probem seems to be exercisers who force themselves to drink large quantities of water during a long athletic event such as a marathon or a hike in the Grand Canyon. They sweat a lot, replace it with pure water, and screw up their electrolyte balance by diluting their blood which leads to swelling of the brain. Here’s a good article.
The best guildline is to only drink when thirsty and not force yourself to drink excess quantities of water.
There was a case of a fraternity pledge in Platsburgh, NY dying as a result of this: Here.