Hydration: How Much Water Do You Need to Drink?


How Much Water Do You Really Need?

Everyone’s heard it: drink 8 glasses of water every day to stay hydrated.

Why do we need so much water? And what happens if you don’t get it?

Here’s the thing – the human body is mostly water. From the time you were just a little nugget, your body was almost 80% water!

Then as you aged and developed, the amount of water starts to drop, but not by much. Adult men are still about 60% water and adult women are about 55%.

All of our tissues and cells need water to keep them moist, flexible and fluid.

Imagine your lung tissues are like a sponge: when they are full of water, they can move and expand to hold the air your breathe. If they are dried out– they won’t be moving and you’ll be suffocating. Not good.

And every day, we lose a good amount of water through our urine and sweat. So that means we need to keep replenishing our H20 intake.


But where did the 8 glasses idea come from?

Mini history lesson for you: in 1945, there was an article published in a medical journal with this magic 8 number.   Eight glasses with 8 ounces – called the 8×8 rule. Super easy to remember, sure.

But there’s no real basis for why the researchers didn’t use another number – like 7 or 10 glasses per day. They tested participants with the 8×8 and found it was healthy. Awesome. But they really couldn’t say that it was more or less healthy than any other number.

So it started grounded on nothing – and now that’s the recommendation everywhere – mostly because it’s easy to remember.


As we (and by we I mean other people) did more research, most hydration gurus will tell you that that 8×8 isn’t nearly enough water for our bodies to thrive.

Here are a few things that happen when you don’t have enough water:

  1. Your brain function slows the more water you lose. 
  2. Dehydration affects your physical performance and decreases your endurance 
  3. And water loss or dehydration can lead to constipation, acne, and even kidney stones or kidney damage.

All good reasons to keep drinking water.

hydration 8 glasses of water in a row

So how much do you really need?

It depends.

Drinking 8 glasses of water may be enough for some people.

But if you do things like workout, sweat, stay active, drink caffeine, or devour lots of processed foods – then you probably need more than just 8 glasses.

If you don’t workout but you eat a whole butt load of fruits and vegetables (since they are packed with natural water) – 8×8 might be enough for you.

(And if you’re trying to lose weight, you definitely need more than 8 glasses – research shows that the better hydrated you are, the more likely you are to lose weight).


Here is the best hydration rule of thumb:

Take the amount you weigh in pounds and divide it by 2. The final number is the minimum number of ounces you need of water daily.

But to really have optimal hydration (and challenge your math skills) you need to increase that final number by 20%.

For most of us – it’s better to drink too much water, than not enough – to account for our morning coffees or workouts, both of which dehydrate us. 

But hydration gets a little more complex than just how many ounces of water you need.

Yes, your body needs water to survive.

But you also need electrolytes.

In order for your muscles and tissues to actually absorb and retain the water you drink, you have to have a balance of water and electrolytes.

But don’t start chugging Gatorade just yet…


What’s an electrolyte?

An electrolyte is a salt that when mixed with water breaks down into ions.

And not to put you back in high chemistry class, but ions are what allows your body to send electrical impulses.

Every signal from your brain to your nerves and muscles travels by those electrical impulses. So ions are important not just for good function, but to keep you heart (a muscle) beating.

So we need water and electrolytes to function.


Shouldn’t we just starting drinking only Gatorade then?

No. Before you jump on the electrolyte craze – you need to know this:

Having too many electrolytes can make your muscles and tissues take in too much water and dehydrate you just as quickly as going without water.

But there’s also an opposite side:

Drinking too much water can actually throw off the balance of water to electrolytes and make you dehydrated.

So we have to figure out how to have a middle ground – the perfect balance between water and electrolytes.

And fortunately – our diets are actually the best way to that.

The fruits and vegetables (and added salts) we eat come with a built in electrolyte to water balance.   So when we have these on our plates, they are already doing all the math equations we need to keep things balanced inside us.  Another huge reason we should keep eating them!

woman hydration with red sports drink

So what’s the verdict on sports drinks?

Unless you’re an elite athlete or training like one, you probably don’t ever need a sports drink.   Your hour-or-so workout isn’t quite long enough to lose enough sweat to throw their hydration/electrolyte balance too off kilter.

And even if it’s off slightly, you’ll probalby rebalance just as soon as you have your first meal or snack.

Skip the sports drinks – especially if they’re filled with sugar or other artificial chemicals.


So what’s the best way to hydrate?

Here’s what we recommend:

  • Get a butt load of veggies and fruit (but mostly vegetables). These are natural hydrators – they are made mostly of water but also contain natural electrolytes to keep you balanced.
  • If you eat a lot of processed food, you need to drink more plain water. Most processed foods are loaded with sodium that increase your electrolyte counts too high.
  • If you don’t drink (much) water currently, start with 8 glasses of water daily as a goal. But because we aren’t all the same size, that’s not enough water for most people. Just a starting place – increase as you get mored used to your water needs.
  • And ultimately, aim drink as many ounces as half your body weight. Then for every 20 minutes of exercise or every cup of caffeinated beverages, add 8-10 ounces extra. That’s your new daily goal.

woman drinking water for hydration


Like this article?  Then check out this one too:

10 Strange Diet Hacks that Might Actually Work

Join Our Level Up Weekly Email

Every Monday we send you 3 easy to use tips to help you find faster fitness results.  It’s not bro-science, just based on real research.  But don’t worry, it’s easy to read and easy to use – and it’s all about finding easier results. 

Start leveling up your week today.



Leave a Reply

Your email address will not be published. Required fields are marked *