8 Glasses A Day?

You’ve heard it your whole life: we need 8 glasses of water per day! But is that really true? Who came up with that?

The Origins of 8 Glasses a Day

Also known as the 8×8 rule for eight 8-ounce glasses per day, this recommendation came into being in the 1940s. Research from Dartmouth University has delved into the 8×8 rule to examine the origins and see if it’s truly the right recommendation.

In 1945, the Food and Nutrition Board suggested that a person consume one milliliter of water for every calorie of food. Based upon a daily intake of 1,900 calories, that’s 1,900 milliliters of water, or approximately 64 ounces. However, this does not include one critical part: that much of the daily need for water comes from the water content in food.

This means that although they recommended 64 ounces of water per day, the Food and Nutrition Board assumed much of that would come from water content in things like fruits and vegetables. It’s important to note that an apple is 84% water, a potato is 79% water, a strawberry is 92% water, a cucumber is 96% water, and so on. This aspect of the 8×8 rule was lost in translation somehow, and people began thinking they needed to drink eight 8-ounce glasses of water each day.

Is There Scientific Proof for 8 Glasses a Day?

Dr. Heinz Valtin, Dartmouth Medical School physician and leader in researching the 8×8 claim, found that surveys of fluid intake on healthy adults of both genders, published as peer-reviewed documents, strongly suggest that such large amounts of water are not needed. The human body is not working on a chronic water deficit, and it will self-regulate.

Dr. Valtin has found “highly suggestive evidence” that we do not need to drink 64 ounces of water per day. Other drinks such as tea can count towards a daily total of fluid intake, and the body probably does not need that many ounces of water each day to work optimally.

However, there are exceptions: Dr. Valtin worked from the assumption of a mostly sedentary, otherwise healthy adult in a moderate climate. If you are exercising, working outdoors in a hot or humid climate, if you have kidney stones or other medical conditions, if you are on a long flight – these are all times when you would want to increase water intake.

What Does This Mean for Incontinence?

If you have overactive bladder syndrome, bladder incontinence, or mixed incontinence, listen up. You may think this means you should drastically cut down the amount of water you drink. But that isn’t really what it’s saying. Although we are debunking the myth that every person needs 64 ounces of water per day, the amount of water you need per day may depend on many factors. Water is certainly necessary to stay healthy and hydrated.

If you have bladder issues, you may be tempted to drink as little as possible. Unfortunately, that can backfire on you. You could get dehydrated, which hurts your overall health. Then, your urine will become more concentrated which can irritate the bladder even more. It is in your best interest to stay hydrated, but the exact amount depends on your activity level, weight, intake of other liquids, diet, and more.

A popular thought now, especially among the fitness community, is to drink half your body weight in ounces per day. This may work for people trying to lose weight, but it could be too much for you. The best thing to do is experiment, see how you feel, and talk to your physician. If you are having bladder symptoms like frequency, urgency, or leaks, you may want to try keeping a voiding diary.

If you are suffering from incontinence, contact us. Or call our discreet, dedicated Medical Concierge at 800-771-1953.

About The Incontinence Institute

At the Incontinence Institute, our team of healthcare providers understand the physical and mental trials that accompany living with urinary or bowel incontinence. Because of this, we are sensitive to your situation and treat all of our patients with the utmost respect and concern for discretion.


Individual incontinence conditions, treatment and recovery times may vary. Each patient's experience with incontinence procedures and / or surgery will differ. All surgical procedures involve some level of risk. If directed to pursue surgery by your physician, prompt action is advised, as waiting may reduce the efficacy of surgical treatment. The opinions expressed in patient testimonials are by patients only; they are not qualified medical professionals. These opinions should not be relied upon as, or in place of, the medical advice of a licensed doctor, etc.

Contact Us

Incontinence Institute 2009 Mallory Lane, Suite 100 Franklin, Tennessee 37067

1.888.741.6403

A