4 Surprising Facts About Hydration

4 Surprising Facts about Hydration

One of the most common questions I hear as a soon-to-be Registered Dietitian Nutritionist and a personal trainer is, “How much water should I drink a day?”

The go-to answer (which I think everyone has heard) is eight glasses a day.

But it’s really not that simple. Men and women need different amounts, children and adults need different amounts, and people need different amounts based on their activity level. Additionally, women need more when they are pregnant or breastfeeding.

To complicate it further, we often hear conflicting information about what constitutes as “water.” Do all beverages containing water count as “water?” Does food containing water count as water? And do caffeinated beverages, which supposedly dehydrate the body, negate the effects of water?

Today I’m clearing up some common misconceptions and providing you with the tools you need to stay properly hydrated this summer. Here are four surprising facts you may not have known about hydration.


The average amount of water adults need is actually between 11 and 15 cups.

According to the National Academy of Sciences, adult women (age 19+) need about 11 cups of water a day, or 2.7 liters. Men should be getting about 15 cups, or 3.7 liters. Children need less, about 5-7 cups.


Food containing water, and all beverages, count toward your daily intake.

This fact is likely the reason for the “eight cups” recommendation. Many foods have a high water content and this water contributes to your daily intake. For example, a cup of oatmeal has about 200 mL of water, which is over 3/4 of a cup.

Additionally, beverages like tea, coffee, soda, juice, etc., are water based and contribute to your daily intake in an equal ratio. One cup of tea = 1 cup of water.

Stay hydrated by making “spa water” using fresh herbs from your home herb garden! >> 

When determining the amount of water you should drink each day, you can minus about 3-5 cups for the amount you get from food and other drinks. This ends up making the recommended daily intake about 6-8 cups for women, and 10-12 for men.

Now I know what you’re thinking — aren’t some beverages dehydrating, and therefore wouldn’t count toward your daily water intake? Well…


Coffee, tea, and even alcohol, are actually as hydrating as water.

What?! Yeah, even alcohol! This fact seems very contradictory to what we’ve always heard, but it’s true. Researchers recently tested a plethora of beverages to determine their “hydration status” and found that caffeinated beverages and beer were able to equally maintain fluid balance in comparison to pure water. Though both are considered diuretics, the effect is not enough to outweigh the amount of water they actually provide.

Now, I’m not saying that you should aim to get all or any of your daily fluids from these sources — obviously there are many reasons aside from hydration why you wouldn’t want to — just that when consumed in moderation, they won’t subtract from your daily intake.


Milk hydrates better than pure water.

The same hydration index study also found that full fat milk, skim milk, and orange juice helped hydrate subjects better than actual water. Researchers believe this is due to their electrolyte content. Nutrients in the beverages may slow digestion, allowing slower absorption into the body and subsequently, slowly release from the kidneys.

This idea supports sports science recommendations to replace electrolytes after strenuous exercise, as opposed to simply drinking water alone.

Don’t feel like drinking milk after a workout? Me either.


Sports drinks like Propel Water have plenty of electrolytes to replace those lost during exercise, without the consistency of milk — or the sugar content of orange juice.

One last fact to keep the fluids flowing properly: a rule of thumb for post-exercise hydration is aim to drink 6-12 oz of fluid for every 15-20 minutes of exercise, according to the National Academy of Sports Medicine.

4 Surprising Hydration Facts

Weigh In: How are you staying hydrated this summer?

*This post is sponsored by Propel but all opinions are my own.


  1. Whitney I love this article! I’m always telling my husband he needs to drink more water because he pretty much only drinks coffee every day. So I was really worried that he was actually losing hydration because of the diuretic effect of coffee, but this makes me feel a lot better knowing that he’s getting some hydration from it! I’m still going to get on his case about the remaining 9 or so cups he needs .

    • Whitney English says:

      Yeah a moderate amount won’t dehydrate him, however you’re on the right track with encouraging him to drink some! 🙂

  2. ok I did not know coffee counted all the more reason to drink more! 🙂
    Deborah @ Confessions of a mother runner recently posted…Cucumber Soba Noodle SaladMy Profile

  3. Very useful information. Good to know. Thanks for sharing!

  4. This is a great post. Thank you. More coffee for me. LOL
    Lauren @ The Bikini Experiment recently posted…3 Butt Exercises for Strong and Lean CurvesMy Profile

  5. I drink a ton of water, but I also drink a ton of coffee, and maybe a little wine too 😉 Glad to hear it’s all hydrating me! Love the post Whit!

  6. What fascinating research! The milk one makes perfect sense when you consider newborn babies!
    Krissy @ Pretty Wee Things recently posted…Raspberry bliss balls | Sugar free, veganMy Profile

  7. Becky Anderson says:

    So interesting!

  8. Shirley Arroyo says:

    We were just having a conversation at Grandma’s about this issue! Thank you for clarifying it. Please continue to share the very useful info you find in your studies 🙂

  9. Amanda Howard says:

    This is a fantastic article! Thanks Whitney!

  10. This is a lovely post Whitney. I’ve been boasting of my water intake, 7 to 8 cups a day. But I can see I should even take more. I take skim milk occasionally so I guess that should also count.

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  1. […] Your body can mistake thirst for hunger. Don’t put yourself at an added disadvantage by becoming dehydrated. Drinking a lot of water and decaffeinated tea throughout the day was very helpful for me. • Buy […]

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