Q: Can a person drink too much water?
A: Drinking too much water is seldom a concern. The body does a good job of regulating fluid intake and output.
A problem called water intoxication can occur in marathon runners and other endurance athletes, people working for long hours in the heat, or even those dancing at all-night parties, often under the influence of illegal drugs.
Caused by loss of sodium from sweating during strenuous exertion, combined with overconsumption of water, water intoxication can produce nausea, fatigue and stupor, and even coma and death. This is not a concern if you drink plenty of water spread out over the course of a day.