Every cell in the human body needs water to function. Water regulates our temperature, cushions and protects joints and organs, and enables smooth digestion. Most of us drink at least some of it every day, but it’s important to be extra careful when the temperatures rise. The facts behind seven debunked myths below should help you stay properly hydrated during the summer months.

Common Dehydration Myths, and the Facts Behind Each:

1. Myth: Dehydration is uncomfortable, but not dangerous.
   Fact: Most people only experience mild dehydration symptoms like headache, sluggishness or decreased sweat output, but it can be serious or even life threatening, requiring medical attention. Fortunately, you can usually prevent moderate dehydration with some extra fluid.
2. Myth: If you’re thirsty, you’re already dehydrated.
   Fact: It’s not too late. In fact, thirst is the body’s way of telling you to drink water, and you’re not at risk of becoming dangerously dehydrated the minute you feel a little parched. “When you get thirsty, the deficit of water in your body is trivial—it’s a very sensitive gauge,” says Dr. Stanley Goldfarb, professor of medicine at the University of Pennsylvania. “It might be only a one percent reduction in your overall water. And it just requires drinking some fluid.”
3. Myth: Everyone needs to drink eight glasses of water a day.
   Fact: This general rule of thumb is outdated. So how much do you really need? The Institute of Medicine (IOM) recommends about three liters of daily beverage intake for men and 2.2 liters for women.
4. Myth: There’s no such thing as too much water.
   Fact: Overhydrating can be dangerous, but it’s relatively rare. Drinking too much water leads to what’s called hyponatremia, which happens when highly diluted sodium levels cause swelling in our cells. But that doesn’t mean don’t drink when you’re thirsty—it takes guzzling copious amounts to cause so-called water-intoxication.
5. Myth: Coffee dehydrates you.
   Fact: Only if you overdo it. While caffeine is dehydrating, the water in coffee ultimately leaves you more hydrated. According to Mayo Clinic nutritionist Katherine Zeratsky, RD, consuming 500 or more milligrams of caffeine a day—anywhere from three to five cups of coffee—could put you at risk for dehydration. So like most things, it’s all about moderation.