September 10th, 2009
09:10 AM ET

How much is too much hydration?

As a regular feature of CNNhealth.com, our team of expert doctors answers readers’ questions. Here’s a question for Dr. Gupta.

From Dayna in Pineland, Texas:

"I have been recently 'diagnosed' with dehydration. I’m drinking more now and have much more energy, but wonder: How much liquid consumption is too much on a daily basis?"


Dayna, there is no single right answer here.  First I’m glad you saw someone about your lethargy and you are taking action to feel better and improve your health.

According to the Mayo Clinic, an average adult loses more than 80 ounces of water every day.  The normal person can easily replenish this by eating and drinking a healthy diet.  But if you eliminate more than you bring in, due to illness or exercise, that is when dehydration can occur.

As to your question;  Your height, weight, where you live, how much you exercise and many other factors determine your need for fluids.  However, you probably have heard to always drink eight glasses of water a day.  And the American Dietetic Association says to drink at least 64 ounces of fluid a day – eight 8-ounce glasses.  But you do get some hydration from your food as well, so it’s safe to take that into account.

You are right to consider how much water is too much because you can over-hydrate.  There is a relatively uncommon condition called hyponatremia.  This can happen in endurance athletes who are losing sodium through sweating and drink only water to re-hydrate.  Most experts will say the key to proper hydration is listening to your body – drink when you’re thirsty.

A good way to check if you’re drinking the right amount of fluids when exercising is to see whether you weigh the same after your workout as before.  If you weigh less, you need to hydrate, but if you have gained weight you need to back off.

Another tip, if you are well hydrated your urine should be nearly colorless or pale yellow.  Also, keep in mind that thirst is often misinterpreted by the body as hunger, so make sure to drink some water at every meal.

Filed under: Exercise • Expert Q&A • Fitness

About this blog

Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.