How Much Water You Should Really Be Drinking Every Day (and How Much More if You’re Exercising)

Perhaps you carry around a water bottle with you at all times to ensure you’re well-hydrated. Or perhaps you’re in the other camp of folks who prefer coffee, tea, and other beverages over plain tap water. Either way, it pays to know how many fluids you should be taking in each day (and how much it can vary depending on your activity level).

How much water you need varies greatly

woman drinking from water bottle

Woman drinking water | M-imagephotography/iStock/Getty Images

You know by now that staying hydrated is essential in ensuring your body functions at optimal levels. But knowing how much water you need per day isn’t as simple as you may think. You’ve certainly heard the 8×8 rule, which states you should drink eight glasses of water that are each 8 ounces per day, Healthline says. But this hard-and-fast rule pitched by health gurus and doctors alike may not be the best advice to follow.

Healthline explains there’s actually very little research that can confirm the 8×8 rule (which, in total, equals a half gallon of water) is one we all should follow. This advice may have started as early as 1945 and has been widely accepted ever since. Nutritionist Frederick Stare also stated in the ’70s that this hydration rule should be followed. But Stare, as well as reports from the ’40s, also said the foods you consume can greatly contribute to your hydration.

In essence, there’s currently no scientific research to suggest you must have eight glasses of water per day to stay optimally hydrated. So, what should you do instead? Listen to your body. If you’re feeling thirsty, that’s your body telling you to drink up. If you do like more strict guidelines to follow, Trent Nessler, PT, also tells WebMD that a good general rule is to drink between half an ounce to an ounce of water for each pound you weigh. For someone who’s 150 pounds, that should be around 75 to 150 ounces per day, for example.

Additionally, feeling fatigued, having a headache, and experiencing mood swings or depression can all occur from mild dehydration. Drinking just one extra glass of water could solve these issues.

How much more should you drink if you’re exercising?

Young woman in sports wear is holding a yoga mat and a bottle of water

Woman with a yoga mat and a water bottle ready to exercise | iStock.com/GeorgeRudy

As Nessler points out to WebMD, you can roughly calculate your daily water needs — and if you’re exercising, you’ll be at the higher end of the spectrum. Lifehacker also explains it may be wise to drink between 17 and 20 ounces of water two to three hours before you even begin exercising. Then, depending on how intense your warm-up is, you may want to drink up to another 8 ounces. While you’re exercising, make sure you’re sipping every 10 to 20 minutes as well.

That seems like a lot of water — and it is. This, of course, isn’t a hard-and-fast rule for everyone. Depending on the climate, what type of exercise you’re doing, the duration, your fitness level, and your age, how much extra water you need to take in varies. But drinking every 10 to 20 minutes, no matter what you’re doing, is never a bad idea.

If you’re exercising intensely for over an hour to an hour and a half, you should also consider a sports drink. These will hydrate you and offer you electrolytes. If your daily workouts are shorter than this, they aren’t necessary, however.

How to tell if you’re dehydrated

The easiest way to check if you’re dehydrated is to look at your urine. It should be light in color and not very aromatic if you’re drinking enough water. When you’re dehydrated, you’ll notice it’s dark in color and most likely has a stronger scent.

You may also notice you have bad breath when you’re not drinking enough water (or getting enough from the foods you’re eating or the other beverages you’re drinking). Muscle cramps, dry skin or lips, and odd food cravings can also occur, according to Everyday Health. When you reach severe dehydration levels, you can also develop a fever or chills.

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