It’s Time to Debunk the Myth of Drinking ‘8 Glasses of Water a Day,’ But We Have a Problem

The amount of water we should drink per day depends on several circumstances.

The myth of drinking eight glasses of water daily
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Staying hydrated has become a modern mantra. It's no wonder: Water is vital to the proper functioning of the human body. Not drinking water kill us in a few days (in contrast, we can go without food for weeks). In addition, dehydration can cause other symptoms without going to that extreme.

Several studies have examined the short-term effects of dehydration. Problems associated with dehydration include fatigue, headaches, difficulty concentrating, and loss of reflexes. However, researchers conducted most of these studies with small samples of eight to 25 participants.

Proper hydration may prevent problems such as constipation, urinary tract infections, and kidney stones in the long term.

Drinking plenty of water is necessary to maintain proper hydration. Our bodies “lose” water in several ways. Urine and sweat are the most common, but we also expel water through our breath and bowel movements.

You've probably heard that you should drink two liters, half a gallon, or eight glasses of water daily to maintain adequate hydration. This isn’t a bad approximation, but many believe it shouldn’t be the guideline.

According to the U.S. National Academies of Sciences, Engineering, and Medicine, the amount of water we should consume is 15.5 cups (3.7 liters) for men and 11.5 cups (2.7 liters) for women. But before you start filling up the water jug, there’s something you need to keep in mind—a lot of things, actually.

First, not all the water we consume is water we drink. According to estimations, food represents 20% of our water. From fruit to rice, vegetables of all kinds, meat, and bread, these foods provide us with water, often more than we think. The 20% figure also includes other beverages.

The beverages issue has generated some debate in this regard. Beverages such as coffee or tea have a diuretic effect, which means that although they keep you hydrated, they also cause you to lose water at a higher rate. It’s convenient to keep in mind, but the diuretic effect isn’t strong enough for these beverages to dehydrate you more than they hydrate you.

In other words, a cup of tea won’t hydrate you as much as a glass of water of the same volume, but it will hydrate you. Recently, a team of researchers found that the beverages with the best hydration capacity, other than water, were milk (especially skim milk) and oral rehydration solution.

Different Factors

But gender and the food we eat aren’t the only factors that can affect the amount of water we should drink daily.

The first has to do with our environment. The climate, the time of year, the weather, and whether you're indoors or outdoors can affect the thermal conditions and humidity of the environment. This, in turn, can affect the amount of water you lose and, therefore, the rate at which you need to replenish it.

I've already mentioned diet, but in discussing its role, I've overlooked foods that can increase our need for hydration. One example is spicy foods, which can cause our bodies to sweat. Alcohol is also one of the most important when consumed in excess, because one of the factors that contributes to a hangover is dehydration.

Of course, physical activity also means you need to drink water. We sweat and lose water when we exercise, which we need to replenish. This is why you should hydrate before, during, and after exercise.

Your overall health can also affect the amount of water your body needs. Diarrhea or fever can make you more likely to become dehydrated. Still, other conditions may also cause you to need more water.

Other circumstances that can cause you to need more water include pregnancy and breastfeeding. This makes sense, considering that in these cases, you're “hydrating for two.”

As with everything, excess has its risks. In this case, drinking too much water can kill you. Or damage your kidneys. Intoxication from too much water causes what experts call hyponatremia, a dangerous lack of sodium.

The kidneys manage much of the water that leaves our bodies, especially when we have too much. However, these organs have a limited capacity. If we drink too much water, either all at once or over an extended period, our kidneys may be unable to keep up.

As a result, water accumulates in our bodies, diluting electrolytes such as sodium. Sodium regulates the amount of water that enters our cells. The lack of sodium eventually causes our cells to swell and fail.

So, how much water should you drink? There’s no magic number. There are so many variables that the best advice is to listen to your body and watch for signs of dehydration. Thirst is the most obvious clue that it’s time to hydrate, but it’s not the only one.

The next one is your urine. Clear or light-yellow urine indicates that your body is properly hydrated. A darker, more opaque yellow suggests that you need to hydrate.

It’s also good advice to pay attention to your circumstances. You should pay more attention to your hydration if you're sweating from heat or physical activity and if you're pregnant or breastfeeding. Older people should also pay more attention to their hydration because the thirst alarm system tends to lose effectiveness over time.

This article was written by Pablo Martínez-Juarez and originally published in Spanish on Xataka.

Image | Pixabay/Pexels

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