Drink EIGHT glasses of water a day. Coffee makes you dehydrated. Drinking extra water can help you lose weight.
You've probably heard of all these before — but are they true? Let’s break down the 3 most common myths about water.
Myth #1: You need to drink at least eight glasses of water a day
Photo Illustration by Becky Harlan/NPR
There isn't actually any evidence that you need 8-ounces of water a day. Researchers in 2022 tried to pin down the claim but there is no rigorous evidence behind it.
However, water is essential for our bodies. It makes up a majority of our blood cells, and flushes out waste through our urine to help cool our bodies through sweat. Not enough water and your cells can shrivel up from dehydration. Too much water can cause swelling from hyponatremia.
So how much water exactly should we be drinking on a daily basis? It depends on your body size, activity level, and the temperature at which you are sweating.
The best advice is to listen to your body. If you get thirsty, drink water. If you are not, you don't need to. This will protect you from the dangers of drinking too much or too little water.
Hydration is also about the balance of water to salt. Sodium is necessary for our nerves and muscles to function. It is what our body uses to regulate the amount of fluid that needs to stay hydrated, and thirst plays a central role in fine tuning that balance. There are sensors in your brain that are constantly checking your blood to see if there's just the right amount of salt. If too salty, then you start to feel thirsty.
If you drink too much water, then your brain detects that your blood is too watery, it releases a hormone that tells your kidney to pee out the extra water.
The takeaway here: Trust your body to let you know when to drink water and when not.
Myth #2: Caffeine makes you dehydrated
Photo Illustration by Becky Harlan/NPR
This idea originated from the findings of a study in 1928 between 3 people. Not only is that an incredibly small sample by today's standard, but the finding has not held up to more recent experiments; studies which have shown that drinking caffeinated and some low alcohol-content beverages such as beer, are not much different than drinking water.
With the exception of higher alcohol content beverages like hard liquor, all liquids count towards hydration. So does food. About 20% of your fluid intake comes from the food you eat, such as fruits and vegetables, and yes, even pasta!
Myth #3: We need sport drinks to replace salt and other electrolytes
Photo Illustration by Becky Harlan/NPR
You might have heard that sport drinks replace salt and other minerals for our bodies when you are active. If you are exercising for more than an hour, it's most likely that you will need to replace the salt that you're sweating out along with water. You don't have to drink sports drinks like Gatorade. You can get salt from other foods and drinks. So once again, the rule applies to trust your body to tell you what you need.
Want to bust more water myths?
The full story is over at NPR!
