Most of us know drinking water is healthy, but...
How much do we need? What's the optimal amount? What if we're trying to lose weight? How does that change if I work out?
These guidelines will answer these questions and help you discover both your basic requirement for and optimal fluid intake.
The truth is, there is no simple formula for calculating your required water intake for an individual. It varies for every person based on age, body size, general state of health, how active you are, and the climate where you live. Basically there is a set lower limit for adequate intake, but no “hard target” of an upper limit. But, knowing more about your body's need for fluids and how to monitor your own hydration signals will help you come close.
Before we get into the nitty gritty numbers... I wanted to share some cool proof of what water can do for you! Your body is about 2/3 water by weight and it's used in every single metabolic process in some way. Here are some of the ways we feel better when we are drinking it:
According to the research adequate fluid intake is when you have “enough fluids to replace losses and provide for solute excretion.” (PMID: 26885571)
According to the U.S. Institutes of Medicine, the general daily recommendations for fluid intake:
The report also outlined that 20% of typical water consumption comes from your food and 80% from all fluid beverages. That leaves us with the following fluid targets:
In their report, the Institutes of Medicine panel did not outline an upper limit.
That said, too much water can cause “water intoxication” and happens when you drink so much water, it affects brain function. The excess water dilutes electrolytes outside of the cells, and since water follows salt, the water swells up inside the cell... this leads to impaired cell function and damage. Basically it's like your brain gets water-logged.
Water intoxication happens when you drink water faster than your kidney's can keep up. These amazing organs can filter roughly 1L of fluid per hour and a total of 28L in a day. So the rule for fluid intake would be not to drink any faster than this.
The first signs and symptoms to watch for: headache, nausea, and vomiting. It gets worse from there if allowed to persist, and can be fatal or put you in the emergency room. (Typically these cases are extreme situations limited to endurance/high-performance athletes and schizophrenic patients.)
There isn't science to back this specific recommendation up, but it remains popular because it's easy to remember. Plus when you consider total beverage consumption targets outlined above, if 64 ounces of the 75-100 ounces recommended is pure fresh water, then you are doing pretty good health wise. (FYI: 64 ounces is just shy of 2L)
Typically, a baseline amount of 2L of pure water per day (in addition to any other beverages consumed) is what I recommend for my patients. If they get sweaty with physical activity via work or exercise, then I add 1L for every hour they work out on top of that.
If drinking 2L of water per day is not currently part of your routine, it can seem like a lot! You may be wondering how to fit it all in.
Here's how to do it:
Alternately... for my patients who have a 30 minute or longer commute:
Some days despite our best planning, these strategies just don't fit into our routine. So the saying I encourage you to keep reminding yourself with:
The only time your urine should be yellow is your first morning pee. After that... it should be a very pale yellow to completely clear. (This changes if you are taking B-vitamins!)
Now, I'd love to hear from you! In the comments below, tell me:
Of course, if you have a question about any of this information, leave it in the comments below, I'd be happy to discuss.
Thank you so much for reading and adding your thoughts! I love getting to connect each week with you like this.
It would mean the world to me if you could share this article with everyone you know who’s been having trouble with their health and wellness. Simple water can make such a big difference!
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