Living in metro Phoenix, especially around this time of year, we all hear about the importance of staying hydrated and drinking enough water.
But how much is actually enough? And what happens if we don’t hit that target?
Stavros Kavouras, a professor of nutrition in Arizona State University's College of Health Solutions and founding director of the Hydration Science Lab, joined The Show to talk about it.
Conversation highlights
We’ve all heard about the need to drink water, and that if you’re thirsty it’s probably too late. Do you get the sense that people here recognize how much we need to drink to stay healthy and hydrated?
STAVROS KAVOURAS: Yeah, this is a great question actually. And, and you touch upon a couple of things. So whether we are well hydrated. And I think the most important question is whether we can rely on thirst. And second, how much we're supposed to drink.
So, so let me take it apart a little bit. So relying on thirst is — I would say relying on thirst or drinking according to thirst is a great survival tool. If you want just to survive, you can rely on thirst. If you want to optimize health, if you want to be like at your best, drinking to thirst probably is not the best way to go.
Is there a good guide that we should be using?
KAVOURAS: So there are dietary guidelines on how much water we're supposed to drink. Those obviously are guidelines that they are designed — like all the dietary guidelines — for population level and not necessarily for individual level. And they're not great for every condition.
So it's not the best for somebody who lives in the winter in Alaska vs. somebody who is down here in the Valley in the middle of the summer, with 110 being almost a daily experience. So, how much we should drink? ... You can use thirst as a first, a warning that you're not probably drinking enough. So having access to water and having water close to you, it's very, very important.
If you notice, I still have not answered your question — how much you supposed to? So, I've been trying to dance around the answer. So instead of giving you an amount, what I would like to give more, which is a little bit more practical, is give some signs that can really help you to stay better hydrated.
And the best signs that I can give that they are based on science and data that we have published over the year — both my lab and and other scientists around the world — is looking at two very specific indices. And one of them — which is very, very simple — is how often you pee? How often you go to the bathroom to urinate? And the second one, how dark is your urine?
So if you're going to the bathroom every two to three hours and if your urine is quite diluted, then both of those are very strong indications that you're consuming adequate amount of fluids. If you're not — so, for instance, you wake up in the morning, you go to the bathroom and then you go to work, and you don't visit the restroom until noon. Probably this is a sign that you're not drinking enough.
Given what we know about the importance of hydration, when you're looking at policies to try to keep people safe and healthy in a place like Phoenix at a time like the summer, how big of a priority for you would be making sure people have access to good drinking water?
KAVOURAS: ... I know it, it might sound a little bit cliche, but water access is a human right. I know some people like to compare drinking water to breathing air. It is very important. It's ... if you follow the dietary guidelines on how much water we're supposed to drink every day, and if you do the math, an average human being consumes close to one ton of water per year. So, so if you compare that, let's say with proteins, we, we consume maybe maybe 40, 50 pounds per year for somebody who is an average body weight.
So, so we really consume a lot of water. And we know even though we need to drink so much water, and even though our body is mainly made out of water, a small decrease in water content — that's little as 1% — we see a significant negative impact on both health outcomes, cognitive function and performance, physical performance.
