KATIE: I'm here with Emma Willingham, a clinical dietitian at Houston Methodist who's board certified in sports dietetics. Hi, Emma.

EMMA: Hello. Thanks for having me, this is so fun.

KATIE: Yeah, of course. You know, we've worked together a lot for the blog, but I think this is the first time we've met in person.

EMMA: I know. That's crazy. We started working together during COVID, so all of our meetings were Teams meeting.

KATIE: Yes. Yeah. It's nice to see your face in 3D.

EMMA: Yes, yes, yes.

KATIE: So, we have you here today to talk about hydration. And I think, you know, we all know we need to drink water — but there seems to be an interest in hydration in the wellness space more and more these days. There are products or services, and we'll get to those, but wanted to start with just simple hydration question. We've all heard eight glasses of water a day. Is this right? Is that too little?

EMMA: That's a really great general recommendation. Normally, too personalize it or individualize the recommendation a little bit more, I usually tell people to aim for half of their body weight in ounces. So, whatever that number is, just cut it in half. That's the amount of ounces of water you should be drinking a day. 64 ounces, though, is a great place to start, or the eight cups of water — especially if somebody feels like they don't drink enough water. And, you know, kind of try to get to that benchmark first and then we can individualize that a little bit more.

KATIE: I personally carry a water bottle around everywhere. I have mine here, so I don't really think of it in cups, I guess…I think it is maybe like liters and things like that. So, we can crunch the numbers unless you have it on the top of your head, but for someone who carries a water bottle around, is that two bottles of water a day?

EMMA: If you're using a reusable water bottle, usually those are about 32 ounces on average. So, you'd want to aim for two of those water bottles, the reusable ones per day. I usually recommend filling it up once in the morning, drinking throughout the morning, 32 ounces, and then refilling and then drinking the other 32 in the afternoon. And if you're somebody who usually uses the more standard water bottle sizes that you would get in a pack from the store, that would be about 16 to 17 ounces. So, you would want to aim for four of those a day.

KATIE: And so that's actually a perfect segue way for my next question. So, you mentioned maybe having one bottle — or two bottles, if it's the smaller ones — in the morning, then in the afternoon repeat. So, need to be dispersing this total water content throughout the day it sounds like? I can't just, you know, at 7 p.m. say, “Oh, dang, I haven't had much water. Let me chug another bottle or so…” Maybe not as helpful?

EMMA: Right, exactly. Yes. You want to spread it out throughout the day, kind of similar to the way that we want to spread out other nutrients, like protein or carbs. You know, we want to try to get those things at every single meal, similar with water. I usually say try to aim for like a cup of water an hour. It is a little bit harder to make up for lost time later in the day. I think that we're all guilty of that at some level. Just because, you know, you're working and the day gets away from you and you're like, “Oh my gosh, it's 2 p.m. and I haven't had any water today.” So sometimes it's a little inevitable, but it is best to spread it out as well as you can.

KATIE: Yeah, I think especially with traveling — I just traveled, and when I travel and I'm in an airport I literally don't think I drink water whatsoever. So, those are kind of those days where I wonder: Am I mildly dehydrated at this point? And, so, I guess the next question really is, when we talk about mild dehydration or, you know, if you just haven't had enough water solely in a single day, what are the effects of that? Is that maybe things you can't quite tell or could it be headaches and things like that?

EMMA: Yeah, it can be a mixture of things. It can feel similar to when you feel low energy kind of from not eating, you know, in a long time. So, a lot of people will start to feel headaches, they'll feel general fatigue, maybe dry mouth. It might be hard to concentrate. And sometimes we attribute that to not eating, but it might actually be lack of water or lack of fluids too. Another tricky one is that sometimes when you're dehydrated, it can actually manifest as feeling hungry so that, you know, makes it a little bit more complicated as well. So, it's important to really listen to your body and really be aware of what you have been drinking throughout the day. And when you start to feel a little bit off, think about, okay, you know, have I been drinking water? If so, when? You know, how much? All of those questions.

KATIE: Yeah, definitely guilty, I think, of maybe seeming like I'm hungry and having a snack instead of water. So, you're a proponent of the: If you're hungry and it's not meal time, have a couple sips of water first and see if it dissipates?

EMMA: Yeah, yeah. I mean, see…if you think back to what you've been doing kind of earlier in the day, if you get to, you know, mid-afternoon and you're like, wow, I'm really hungry…but I just ate lunch not that long ago. You know, it might be water that you actually need, but, you know, kind of try to assess it in the scheme of your overall day.

KATIE: Got it. Yeah. And then beyond someone's overall day, what do we need to know about dehydration in this larger context of maybe you're a person who regularly does not drink enough water. What are some of the kind of effects that can come out of that?

EMMA: I think one of the most significant ones is that it can strain your organs — just because your organs need that fluid to be able to work efficiently and optimally. And, then, that can then manifest in your just day to day routine and kind of the way that you operate, your productivity, things like that. And a lot of it is kind of what you're mentioning earlier, things that we might not even realize. There was a really interesting study that was done analyzing dehydration when it comes to the effects of driving. So, it actually — the researchers found that people who were dehydrated had slower reaction time when they were driving. They were less likely to, you know, pay attention to the road, as well. And, so, that was a really good example of just the little things that we do on a daily basis that can be impacted by dehydration.

KATIE: So almost like an equivalent to being hangry?

EMMA: Yes!

KATIE: You know, when you're hungry and you get kind of irritated. Maybe it's if you're mildly dehydrated, your productivity goes down and maybe your reaction time. So that’s interesting, I didn’t know that.

EMMA: Yeah. Definitely. It's very interesting.

KATIE: For more obvious symptoms of dehydration, are there some ways people can easily tell that, okay, I'm dehydrated, it's time to really focus on water?

EMMA: Yeah, there are two ways that you can really measure or visually see how dehydrated you are, or the impacts of that dehydration. One of those is going to be just assessing the color of your urine. So, the more clear it is, the more hydrated you are. If you start to creep into like the, you know, apple juice, darker looking category — TMI, but it's helpful — that's when we are like, okay, we need to really bump up the water intake in prioritize hydration a little bit more. Another way is weighing yourself before and after you exercise. So, if you weigh yourself before you, for example, go on a runner, a bike ride, and then weigh yourself after when you get back, however many pounds of water you lost or pounds of weight, you know, that is measured on the scale, you would want to replace that with about 16 to 20 ounces of water. So that that can really tell you in real time, OK, wow, I lost this much fluid. I need to replace it.

KATIE: Yeah, that also sounds interesting, too, because it's just that reminder that, man, you really can lose a pound of weight just from water alone and maybe a long workout or something. It's a nice reminder of how important that is.

EMMA: Yes. Yes. And how easily it can be lost. Yeah, definitely.

[Music plays to signal a brief interjection in the interview]

ZACH: Water isn't the only thing we lose as we exercise — or do anything that causes us to sweat, for that matter. Electrolytes are lost, too. These are essential minerals that, among other important roles they play in our body, go hand in hand with hydration. One of these electrolytes in particular, sodium, is key in helping us hold on to water and maintain optimal fluid balance. This means that we need to replace the sodium and other electrolytes we lose throughout the day, especially after sweating, in order to prevent dehydration. Fortunately, these minerals are fairly abundant in the foods we eat, but you can also get electrolytes from certain beverages — something that will come up a lot throughout the rest of Emma and Katie's conversation.

[Music ends]

KATIE: What are some of the things — even if we are drinking enough water — are there things that can dehydrate us on top of the water we're already getting?

EMMA: One thing that is a little bit controversial is caffeine intake. So, some people will say, oh, caffeine is very dehydrating. Some people count, you know, sources of caffeine like coffee or tea as fluid intake. I'm kind of in the middle. I kind of feel like it depends on, you know, where the caffeine is coming from, how much you're having, that kind of thing. Like if you're having a cup of coffee or tea, that could probably contribute to better hydration. But if you're just pounding coffee all day long, that's probably going to put you in a deficit. When it comes to water balance, alcohol, we know, is also very dehydrating and hence the reason why a lot of people reach for, you know, Pedialyte or Liquid I.V. or things like that to kind of help counteract some of those effects.

KATIE: Yeah, absolutely. What about really salty foods? Is that just a thirst to kind of help us drink or we actually dehydrating ourselves at that point, when we have a really salty meal?

EMMA: Yeah. So, salty food like salted nuts or, you know, I think of soy sauce, something like that, that won't necessarily make you dehydrated, but it will trigger that thirst mechanism. [And this also explains] why a lot of electrolyte supplements are really helpful. Because, you know, if you have somebody exercising, for example, the salt that's in those electrolyte supplements will actually kind of induce them to drink more water. So that's what happens with these salty snacks. They will add more sodium to your bloodstream, which will then create that effect, but they won't dehydrate you in the same way that, you know, not drinking fluid does.

[Music begins to play]

KATIE: We've covered a lot of the hydration basics at this point. Up after the break, we'll talk about products claiming they hydrate better than water, how we all sweat differently and what this means for how we rehydrate. When exactly you should choose a sports drink over water and even whether the age of your water matters.

[Commercial break]

KATIE: Back to dehydration, or maybe even just the average person who isn't even dehydrated, is otherwise healthy. There's a lot of products out there to help us stay hydrated. And the one that I'm thinking of in my mind, you know, there are sports drinks — those have existed for a long time, they were designed with a very particular purpose I think, we will get to those actually in a minute.

EMMA: Sure.

KATIE: Before we get to those, the thing I've noticed recently is these packets that, you know, have solutions in them or powders that claim to hydrate better than water, quote unquote. So does an otherwise healthy person who, whether they're getting quite enough water or not, do they ever need to be hydrated better than what water can hydrate you?

EMMA: So, it's very situational and could create like a tree of decision making when it comes to hydration products and things that can help in addition to just your regular water intake. The main things that would increase your fluid needs, or need for some of these other products, would be the environment that you're in, if you're exercising, if you're somebody that sweats a lot. So, if you are somebody that is exercising, you know, right now outside in Houston, when it's 120 degrees, very humid, you're probably going to be losing a lot of salt through your sweat. And so in that case, we need to replenish what was lost — which is when some of those other products can come in handy. If those products are being used more for somebody who's pretty sedentary — they're working inside all day, not exercising a lot, those things are probably not as helpful. They are adding more salt to your bloodstream and increasing your blood pressure and things like that. But if they're used carefully and considering, you know, other environmental factors such as heat, humidity, exercise, you know, the length and duration of your exercise, they can be helpful.

KATIE: Okay. So, these hydration multipliers may even have some detrimental effects in some cases. So, they're not even just not beneficial, they might even be kind of excessive to the point of harm.

EMMA: Yes. If they're being used incorrectly or when they're not needed. For example, I mean, some of those products can have up to 500 milligrams of sodium in them, which is pretty substantial if you're not losing that sodium through sweat or, you know, other losses. And, so, it's important to use those for the purpose that they were created. Part of the enticement too, I think, is that a lot of them taste really good and they have good flavors, which then makes you want to drink more in addition to the sodium making, you want to drink more. So, there's a lot of factors that can go into it, but yes, if they're not used for the purpose that they were created, they can actually do more harm than good.

[Music begins to play]

ZACH: To understand why we should take Emma's warnings seriously, it helps to understand what happens in your body when you take in more salt than you actually need — whether that's through incorrectly using hydration packets or just eating a really salty meal. Your kidneys are always helping balance the amount of sodium in your body, retaining what you need, and filtering out what you don't. They get overwhelmed when large, unnecessary amounts of salt are consumed. The excess sodium that your kidney struggle to filter builds up in your bloodstream, which your body then tries to dilute with water. This increases your blood volume, causing your heart to pump harder and increasing the pressure in your arteries. Hence the increased blood pressure Emma mentioned. This increased pressure places stress on the blood vessels and every organ of your body. It's why consuming too much salt can, over time, cause a range of health issues, including high blood pressure, heart disease, stroke and kidney disease.

[Music ends]

KATIE: You've mentioned sodium and sweat now, and it reminds me of a conversation you and I have had while talking about some blog posts — and I don't think we ever actually turned this into a blog post yet so it’s perfect that this is coming up on the pod. Sweat. We sweat out electrolytes, namely sodium.

EMMA: Yeah.

KATIE: But I remember you telling me one time that everybody sweats differently. And not even just the amount. We all sweat out different levels of these electrolytes. Can you talk us through that a little bit more? I found that so fascinating when you talked about.

EMMA: It's super interesting. So, the main electrolytes that we have in our body [are] sodium, chloride, potassium, magnesium and calcium. And, a lot of times with electrolyte products and when someone is assessing how much they're sweating, they think that they need to replace all of those electrolytes. But, in actuality, the majority of the electrolytes that we lose through sweat are going to be primarily sodium and then a little bit of chloride. And then even with that, each person and each individual, you know, loses different concentrations of those electrolytes through their sweat. So, you might have somebody who is a really, really salty sweater — they exercise outside and you can see the salt collecting on their clothes or the rim of their hat. Whereas somebody, another individual, might be doing the exact same activity in the same environment, they're also sweating a lot, but they might be losing only water and not as much sodium. So that's where, you know, there are some new techniques and research and things like that that have been focusing specifically on that topic and how to address, you know, individualized sweat concentration. And it's really interesting, you know, who would have thought that there could be a whole research topic on just sweat?

KATIE: Yeah. When you brought it up, I found it so interesting. I've seen athletes will have their — you can tell they have a specific mix or they’re drinking or a specific bottle. And I think that probably explains it. And I have seen those services where you can test your sweat.

EMMA: Yes.

KATIE: And some of it is — I don't really necessarily probably need to worry about it too much — but as a person who finds it interesting and likes like data and information about myself…

EMMA: Yes!

KATIE: I’m always so tempted to be like, ooh, do I sweat out more sodium or do I sweat out, you know, less potassium than most people?

EMMA: Yeah. And it can be helpful, too, because, I mean, there might be somebody who they're exercising and they're sweating a lot and it might not even be a huge amount of activity. They just are a heavy sweater. And they might feel like, oh, I really don't really need an electrolyte supplement or I'm good with just water. But if they're sweating out a lot of salt, it can be helpful to add an electrolyte supplement in, which is where that information and kind of knowing that about yourself can be really helpful. So hopefully there continues to be more research and products and kind of toys that we can play with too to really determine what each person needs.

KATIE: When we talk about sports drinks versus water, just as a general topic, when should someone —you know, we've sort of alluded to the times when a person might consider either sipping on a sports drink alongside water or potentially even swapping water with a sports drink — what are those specific times? If you had to list like your top five or six times you would say, okay, really do think about sipping on a sports drink.

EMMA: Okay, yes. So, there are two different categories of sports drinks, too. We know that there are a lot of brands that are sugar free. So, they have the fluid and the electrolytes, but they don't have the extra carbohydrate. And then there's another category with just the regular like full sugar, full electrolyte plus fluid option. So, sports drinks can be very helpful because they accomplish a lot in just a small amount of liquid. So you get your fluids to help you rehydrate, you get your electrolytes to help you rehydrate, and then the carbohydrates come into play when we're looking at how long your activity is lasting — also potentially how intense your exercise is. So, the longer you are sweating, the longer that you're exercising, and the longer or the more intense that your exercise is, the more we need those carbohydrates, which is where the carbohydrates in a sports drink. And that sugar can really come into handy because those are specifically formulated for that purpose, to give you a really fast-acting, quick-digesting source of energy. So usually say, as a general recommendation, that threshold is if you're exercising over an hour, then you might want to think about starting to sip on a regular sports drink so that you can get some additional carbohydrates, especially if your exercise is really intense because you will be relying more on carbohydrate for fuel and need more of that, that sugar. If you're exercising for less than an hour, but you're still sweating a lot — you're doing really intense exercise where your heart rate is up — you might want to consider either a sugar free electrolyte drink or regular sports drink.

KATIE: Got it. Okay, that makes sense. Another question about electrolytes in our water. So, for people who use or for people who drink filtered water, I'm wondering if there's any concern there. So, for instance, I primarily fill my water bottle up from my refrigerator. So, it's filtered water that comes through, and I've read or I've heard that electrolytes can be stripped out in this case, sometimes even some of the minerals and things can. Obviously the contaminants are stripped out, which is why we're we're using the filtered water. But do people need to worry if they're primarily drinking filtered water and try to replace electrolytes some other way?

EMMA: I don't think they need to worry unless they're, you know, losing a lot of fluid or, you know, exercising heavily or, you know, those different examples that we've discussed — just because there isn't, there shouldn't be really a strong additional need for electrolytes that are, you know, outside of your water, even if it is filtered. If you're not, you know, doing some of those things. And we also do get some electrolytes from our food, which I think sometimes is forgotten. So, if you're eating even a mildly salty food.

KATIE: I’m sure, we get a lot from our food.

[Laughs]

EMMA: Yes, exactly. If you eat out, you know, usually there is some level of sodium added to that just for flavor and, you know, preserving the food and whatnot. And we can also get fluid from our food, too. So those two kinds of factors really go hand in hand. Plus, your water. You should be fine if you're, you know, just going about your day. But if you add something in that's more strenuous where you are losing that fluid, then we might want to turn to some of those other products where the filtered water, really any type of water, it just wouldn't be enough.

KATIE: That makes me feel better. I read that recently and was kind of like, “Whoa!” Most of my water is coming from my filtered refrigerator.

EMMA: Yeah. And there are some waters, too, that advertise to have electrolytes in them. So, you really want to probably look at the label like if you're using those for replacing, you know, what's lost. You want to look at the label and it should have at least 200, 300 milligrams of sodium if you're using it to replace what you're losing.

KATIE: What about pH with water? I've seen a lot of the kind of alkaline waters or pH-balanced water. You know, electrolytes are important, but is the pH of the water we drink important at all?

EMMA: Those are super trendy. I know exactly what you're talking about. Our body does a really good job just naturally regulating our pH. And so alkaline water versus, you know, not as alkaline water, I look at it all in the same category. And so, you know, one versus another is not necessarily better or worse. But yeah, those are definitely really hot right now.

KATIE: Yeah, I was at a friend's house recently and they offered me one and I was like, hmm, okay.

EMMA: They do have a different taste.

KATIE: Oh, that’s interesting.

EMMA: Yeah. I can't really put my finger on what exactly it is. Yeah. But it's interesting.

KATIE: Yeah, definitely. So, we've talked a lot about water — getting enough water, I guess I should say.  And to close out, I think really the last thing I wanted to talk about is too much water. Do we need to be worried about over hydrating in our lives? Is that common? Do these hydration products put us at risk for being over hydrated?

EMMA: It is definitely something to think about. Like anything, you know, too much of anything, even if it's a good thing, can become a bad thing. If we're spreading our water intake out throughout the day and meeting our needs, we should be completely fine. But there are a lot of cases where, you know, I always think of people who are, you know, dieting or who are like, you know, bodybuilders, for example — they're carrying around, you know, a big jug of water and drinking a ton of water throughout the day. And if you're going way over your needs, you can overload the body and really dilute the sodium content that's in your bloodstream. And that's called hyponatremia, which can be really, really dangerous and life threatening if that is happening. It is not very common, but it's still, you know, a possibility, a very real possibility that people just need to be careful about if, you know, they're all of a sudden really increasing their water intake. You want to try to do that within a reasonable limit.

KATIE: All right. Well, thank you so much for joining us today. This was really great. I think it gives people a good landscape of what matters with hydration, what maybe doesn't, or maybe when it does matter and things like that. So, we really appreciate you coming in.

EMMA: Thank you. Thanks for having me. It's always fun to chat.

[End of interview]