I never thought that drinking too much water, especially during sport, could even be an option. Let alone it could be bad!
A group of experts in sports medicine has in fact drafted the new guidelines, which suggest not to exceed, and drink only when you feel thirsty.
Clinical Journal of Sport Medicine explains that
Drinking too much water to prevent dehydration is not necessary and it is dangerous
Until now, we have all learned that when we do sport activity we should start drinking before we feel thirsty, especially when we're sweating a lot, because dehydration can cause medical issues.
The experts continue: "Unfortunately this advice increased the mistaken belief that thirst is a poor indicator for the replacement of fluids when you start sweating. This has led many people to drink too much water or workout drinks in general.
The Risks of Drinking Too Much Water
At least 14 athletes, including a woman who died two days after running the Marine Corps Marathon in 2002, are believed to have died from drinking too much water while exercising.
When there is an excess of fluid in the body, the concentration of sodium decreases abruptly and the kidneys, now overloaded, are not able to dispose the load of water.
The cells begin to absorb it, and this can lead to a swelling of the entire body, with the risk of seizures, coma, or even death.
The experts recommend to treat hyponatremia with a saline solution three times more concentrated than normal saline solutions given to re-hydrate patients.
How to Dose Water Intake
It is true that too much water can be harmful to the body and also for the athlete, but it is equally true that dehydration, even just of 2% of the body weight, leads to a sharp deterioration of performance and higher and serious health consequences such as heat stroke, not so uncommon in many sports competitions.
For example when, after sports, you lose a pound of weight, it is almost all water, and for a person weighing 100 lbs it is 2%.
So, weighing yourself after a training session or a competition is useful to tell if you have been drinking too much (weight gain) or too little (excessive weight loss, more than 2%), so that you can regulate.
Even the color of your urine may be a good indicator.
When it's too dark it indicates dehydration, while urine lighter than normal means overhydration, therefore that you have been drinking too much water or other fluids.