Can you drink too much water?
Can you drink too much water? Or put another way, can drinking too much water be harmful? The answer is yes. As our colleague Aitor always comments, the dose makes the poison, and drinking too much water can be as bad for our body as stopping, although obviously it is necessary to drink a lot, a lot of water.
How can drinking water be bad?
Many of you are probably thinking about the harmful effects that chlorine or mineral residues in water can have on our body, but what makes too much water does not feel good on our body is something much more basic.
As you all know, water represents 60% of our body weight. It is not that we are filled with it, it is simply part of our cells, tissues and organs, and serves to transport nutrients, regulate body temperature and eliminate toxins.
On the other hand, in the same way that we always maintain the same body temperature, it is also important to know that for the proper functioning of our body it is necessary that the water always have the same concentration of electrolytes. This balance is part of the homeostasis of the human body, and in the case of water it is achieved through osmoregulation, which is the exchange through a membrane of two liquids with different concentrations of electrolytes.
Thus, if we stop drinking water and lose it through sweating, the cells "release" water to maintain this concentration of electrolytes - the headache of a hangover is largely due to dehydration of the meninges - and if If we do not drink long enough - around three days - or lose a lot of water, severe dehydration can lead to death.
If, on the other hand, what we do is drink a lot of water, as it has a lower concentration of electrolytes than necessary, what the body will do is get rid of it through the urine. For this reason, for example, to hydrate ourselves when we do sports it is not only necessary to drink water, but also to recover electrolytes, either with an isotonic drink or with products rich in mineral salts.
What happens when we drink too much water in a short time is that our kidneys are not able to get rid of the liquid at the rate at which we ingest it, and then what the cells do is remove that water from circulation to maintain balance. It's not that they do it intentionally, it's how osmoregulation works. By absorbing the water, the cells swell, which can be really problematic in the brain, as it is limited by the skull, causing headache, confusion, coma or even death.
So should I drink less water?
No. Although the popular recommendation to drink eight glasses of water a day has no scientific basis and it is generally best to drink when we are thirsty, which is why our body has our way of telling us that it needs water, it is necessary to drink much more water for this type of poisoning to occur.
The greatest risk situations occur when we are subjecting the body to a prolonged effort, such as a marathon. In these circumstances, the body makes an effort not to lose too much fluid, which together with an exaggerated intake of water during a refreshment station or at the end of the race, can lead to mild cases, showing that yes, you can drink too much water.