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May 10, 2017

Infrequently Asked Questions: Do I still need to drink eight glasses of water per day?

Anyone who's gone through a grade-school health class recalls the lecture: Drink eight 8-ounce glasses of water per day, at least, to stay functional. 

It's memorable; it's catchy; it's easy. But is it true?

Curious to find out, we reached out to Jefferson Health's Josh Okon, assistant director of the university's Primary Care Sports Medicine Fellowship.

I don't think most people have gotten an update on how much water they need since they were schoolkids. So what's the deal in 2017: How much water do we need, and is that 'eight glasses of water' notion applicable anymore?

The eight glasses of water thing is certainly not what we go by anymore. When I was a kid, that's what people used to tell us, but there really is no exact amount you're supposed to drink daily. Really, think about three rules of thumb.

One is that you should drink water, or some kind of water-based beverage, with every meal. And you should drink water when you feel thirsty, when your mouth feels dry. The third rule is to monitor your urine. Basically, when your urine is clear or light yellow, that's good. And when it's yellow or darker, that's not good -- that means cells are shrinking and you're not getting enough hydration. If you follow those rules of thumb, you should be OK. And if you look at the CDC website or any of the medical websites, you'll find those three things.

So, with the urine test, does vitamin intake or other nutrient intake impact your urine color?

Not that I'm aware of, honestly. And I think the color is from the ammonia you give out. Basically, if you have enough water, you're diluting it enough so that it becomes clear. You want it as close to looking like water as you can get it. And while we don't have exact numbers anymore, I think averages -- for an average-size man, there's somewhere around 3.2 liters of water per day [recommended], which is somewhere around 16 glasses of water, not eight. And women, it's between 2 and 3 but closer to 3, and more like 12 cups of water. The reason we don't recommend specific amounts anymore is people are different sizes, live in different climates, are at different levels of activity-- you need more water if you're more active. There are lots of reasons.

Why are sugary beverages not recommended for hydrating?

You can still get hydrated drinking sugary beverages, the problem is that -- drinking sugar, A) You're going to gain weight --it's not healthy. And even diet beverages, without getting technical, you gain weight with those because you're tricking your body into thinking you're drinking a sugary substance, and your body releases insulin to try and deal with that which can make you feel hypoglycemic, so you get hungrier and drink more.

Is Gatorade worth it for the electrolytes?

Yeah, if you're losing a lot of your moisture in your body through sweat -- if you're active and lick the sweat off your face and it's salty, you're losing a lot of sodium in that moisture. Sodium and other types of electrolytes are also important for your cells to function normally. So when you lose a lot of moisture through sweat or sitting outside on a hot day, it is important to hydrate with electrolytes. Sometimes, when we cover games on the sidelines and don't have Gatorade, we'll even hand out salt tablets with water.

We also get hydration through food, right? But are there better foods for hydrating than others? I imagine you're not loading up on water if you only eat bread.

Fruits and vegetables that have a high water content. On average, you get about 20 percent of your water through food -- if you eat a good diet, from your food.

And you can't frontload water in the beginning of the day, right?

This would be a useful time to look at your urine, but yeah. You'll pee it all out if you do it all first thing in the morning. You'll be dehydrated by the end of the day. You want to break it up and hydrate throughout the day.

Can you drink too much water?

Yeah, but it's hard to. It's actually really hard to drink dangerously little and dangerously too much, to be honest. If you're dehydrated throughout the day -- let's say you go to work and you just drink a cup of coffee with water and only a bit [of water] with dinner, you'll be dehydrated and feel thirsty. You might feel tired and if you try to exercise you might cramp. But you won't drop to dangerous levels where you have to go to the hospital. Conversely, if you drink a ton of water, it's really hard to get water poisoning. That said, you hear about instances on college campuses where they have challenges -- that's dangerous and you could die from it. The normal human being not drinking much water throughout the day or pounding water won't feel many consequences. 

What are the general consequences of not getting enough water on a daily basis?

If you're dried out, you'll feel fatigued, tired, your muscles will cramp, you'll feel nauseous and get a headahce. And those aren't life-threatening. If you have life-threatening dehydration, if you have a horrible diarrheal illness or vomiting illness, that's when things start getting dangerous. Or if you have a more serious issue with your kidneys, but that's not normal.

Anything to add?

I was joking with a colleague -- when I was a kid we were in summer camp and there was a stupid saying in Hebrew we used to say, and he said he'd buy me dinner if I got it in the article. So I'll just tell it to you. We used to say in Hebrew, "Pee pee lavan metzuyan" -- white pee -- is excellent, and "Pee pee tzahov zelotov" is no good. [Laughs]