Hyponatremia in marathon runners

The word is getting out that overdrinking is more of a risk than underdrinking for endurance athletes. Too much water leads to low levels of sodium (aka hyponatremia) and can be very bad news.

I can't believe this statistic is true, however

Last year, one percent of the more than 35,000 New York City marathoners were hospitalized with hyponatremia, Maharam said, and although that is a smaller toll than in other cities' marathons, doctors say every one of those life-threatening medical emergencies could have been avoided.

That would mean 350 hospitalized runners with hyponatremia. I just can't see that.

The example used in the article is a runner who became hyponatremic at the 2004 Boston marathon. He was basically turned away at the medical tent after the race because he looked too well. I ran that race and it was horrible. After a cold spring it got close to 90 on race day. I remember finishing (about 4 hours elapsed time, 4:20 clock time) and seeing a line of wheelchairs waiting to get into the medical tent!