Yes, you can drink too much water and die - or at least get an expensive ambulance ride to the hospital. Marathon race directors have feared this problem for several years now. Marathon and shorter-distance race participants have sickened and some have died by drinking too much water and/or sports drinks during running and walking events. Personally, I saw walkers from the Breast Cancer 3-Day Walk taken by ambulance to the hospital gravely ill from drinking too much on a hot 20-mile day, including the mother of a walking friend. A study found that the slower the runner/walker is, the more likely they were to drink too much during a race. While many coaches had been advising to drink electrolyte-balanced sports drinks rather than plain water, research points to the sheer volume of fluid to be a problem in either case.
Unfortunately, coaches and event directors had been pushing "drink, drink, drink" as a mantra to prevent dehydration. You will see the dangerously outdated advice everywhere. This has been revised to "drink when thirsty." Marathon participants should weigh themselves before, during, and after long distance training runs and walks to see precisely whether they are drinking too much or too little - they should have no weight change, up or down, from the start to the end of the walk. Any weight loss shows losing too much water (dehydration), while gaining weight means you are drinking too much and heading towards hyponatremia.
Dieters can also get bad advice that they need to drink, drink, drink - and may end up drinking to excess. If you are starting a new diet, let your body and thirst be your guide. Your body really does know how much fluid it needs, and it lets you know by being thirsty - but switch to non-caffeinated drinks such as water. If your urine is dark yellow during the day, you probably need to drink more non-caffeinated liquids such as water. If you find you are drinking so much that you are racing to the bathroom continuously and your urine is so pale it doesn't even look yellow anymore, back off on drinking so much. If you decide to drink a little extra, drink only a cup of water at a time - 8 oz, not the full water bottle, and wait until you feel thirsty.
If you are on any medications, consult your physician before significantly increasing or decreasing your fluid intake. And, don't enter any drinking contests of any kind!
- Drinking Guidelines for Runners and Walkers: May, 2006 International Marathon Medical Director's Association.
- Water Intoxication and Hyponatremia Symptoms and First Aid
- What Happens During Water Intoxication?
