8 Hydration Myths that May Surprise You

Eight Hydration Myths


I don’t know about where you live, but here in Virginia it is hot and humid.  The weather has been the kind where when you go outside and in a matter of minutes you are a sweaty mess.  We’ve all heard about the importance of drinking enough water.  Today I’m sharing some surprising myths and truths that I learned about hydration from Runner’s World Magazine.


Myth:  Drink eight glasses of water a day.

Truth:  Most people meet their water needs by letting thirst be their guide.  Eight glasses is an arbitrary number.  91 oz per day for women and 120 for men is a better guide.  (Don’t forget that foods count toward your recommended intake number.


Myth:  Clear urine means you are hydrated.

Truth:  Clear urine is excessive.  A pale yellow, like lemonade, means you are hydrated.


Myth:  Caffeine dehydrates you.

Truth:  Caffeine doses between 250 and 300 mg – about 2 cups of coffee – will minimally increase urine output for 3 hours after consumption.  Research shows that exercise negates those effects.  If you run within 1 to 2 hours of drinking coffee, you don’t urinate more because blow flow shifts toward your muscles and away from your kidneys.


Myth:  Thirst isn’t a good hydration tool.

Truth:  Thirst is a very strong predictor of hydration needs.


Myth:  Pure water is best for hydration.

Truth:  For an easy, hour-long run on a coolish day, plain water is fine.  If you run long on a hot day and are a heavy sweater, drink something with sodium in it like Gatorade.


Myth:  You can’t drink too much.

Truth:  You can drink too much and it can be deadly.  If you drink too much, you are in danger of hyponatremia, a condition where the sodium levels in the blood become dangerously low.  My friend once was hospitalized for this after she drank a bunch of water following a hot run.  A better choice would have been Gatorade.


Myth:  Drinking lots of water is a good way to “detox.”

Truth:  There is no evidence that drinking water makes your body more clean.  Too much water can slightly impair the ability of the kidneys to filter blood.


Myth:  Staying hydrated eliminates your risk of heat stroke.

Truth:  Body size, exercise intensity, fitness level, and age along with humidity and air temperature can affect who does or doesn’t develop a heat stroke.  Dehydration can make you more prone to heat stroke but it isn’t the only factor that causes it.


Do any of these surprise you?  My favorite surprise is that my morning 2 cups of coffee don’t dehydrate me after all.  Yippee!  I can now run with my coffee buzz and feel good about doing so.




  1. I was really surprised about the over hydration. I’ve never, ever heard of that before! I always figure that I don’t want Gatorade b/c it has calories, and I’m trying to burn calories… but, wow. I’ll reconsider. Great myth busting, Paula! 🙂

  2. This is all based upon opinion and little research. Humans are made up of water and you can never get enough of it. After a long run you shouldn’t be stupid enough to not replenish what you just burned ie. sodium, water, and sugar…but water is the one thing you should and need to replenish with. Also I am a person who only drinks water and just water and my kidneys are as healthy as can be and filter my blood perfectly….because blood is mostly made up of water.

    1. I doubt if Runner’s World Magazine would publish these facts if they were not based on research.

  3. What great information about hydration and water. Although hydration is incredibly important, there are some things that we just don’t think about. Thanks for informing us 🙂

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