How Much Water Should You Drink, By The Numbers

We separate fact from fiction on how to stay hydrated.

We have all heard the adage that you need water. But why is water important for your body? And what are the benefits of water? We have answers to these questions along with the numbers on how much water you should be drinking so you can stay happy, healthy and hydrated.

mineral water being poured into clear glass
getty images / Jose A. Bernat Bacete

What are the Benefits of Water?

Drinking water has many benefits and it is important for many functions in your body. First and foremost, your brain needs water to stay focused, motivated and keep a stable mood. Being dehydrated can reduce oxygen flow to your brain and simply be distracting from the task at hand. A dry mouth is more susceptible to bad breath and unpleasant tastes, which can even promote cavities. When you are dehydrated, your skin is less elastic. For this reason, skin that is chronically dehydrated is more prone to wrinkles (though drinking a ton of water does not prevent wrinkles).

Being dehydrated also takes a toll on your heart. When you have less water in your body, your blood volume is lower. This makes your heart work harder to get enough blood and oxygen to your organs and muscles, which is why exercising when dehydrated is so strenuous. Also, your blood vessels close to your skin's surface expand to release heat when you are too warm. When you have lower blood flow, it takes a higher temperature to get your blood vessels to expand, so you stay hotter.

Contrary to popular belief, water is not directly responsible for muscle cramps, but it is related. When you are dehydrated, your muscles receive less oxygen and blood from your heart. This makes your muscles become more fatigued faster, and fatigue causes muscle cramps. Water does help remove waste from your muscles as they contract and lubricates your joints, so it is still crucial for exercise. The waste from your bloodstream is filtered through the kidneys and excreted, so being severely dehydrated can build up toxins in your kidneys and, in extreme cases, cause them to stop working.

How Much Water You Should Drink a Day, By The Numbers:

  • 91: Number of ounces of liquid (from food and drink) most women need daily. Men, add 34 ounces. But this is an estimate. "The best way to make sure you're hydrated is to check your urine," explains Rahaf Al Bochi, R.D.N., L.D. "It should be a very pale yellow." Darker? Drink up.
  • 7-10: The number of ounces of water you should drink ­every 10 to 20 minutes during exercise. Aim for more the harder you work.
  • 3: Pounds of water weight lost (from sweating or inadequate H20 intake) that can reduce attention span and cognitive function in a 150-pound person. Sweat rates vary, but you could lose this much exercising moderately for 90 minutes on a warm day.
  • 37, 46, 17: Percentages of daily fluid the average American adult gets that comes from plain old H20, other beverages and food, respectively.

5 Easy Ways to Get Your Fill

  • Sip iced tea or ­coffee. Even though caffeine can have the opposite effect, studies show that these sips are still hydrating.
  • Jazz up your ice. Bored of tap? Freeze pureed strawberries, basil and lime juice in ice cube trays. Serve in seltzer. Or try one of these other DIY Easy Flavored Ice Cubes.
  • Raise a beer glass. Enjoying one low-­alcohol brew (under 5% ABV) can be just as hydrating as H2O ­after exercise.
  • Munch some cucumber. It's 97 percent water. Strawberries and watermelon are other top picks at 91 percent.

Read on:

Does Seltzer Water Have Any Health Benefits?

How much water should I drink? 5 myths about hydration answered

Was this page helpful?
Related Articles